TWI490485B - Copper nanoparticles and maufacturing method thereof, and method for detecting amino acids by using the copper nanoparticles - Google Patents
Copper nanoparticles and maufacturing method thereof, and method for detecting amino acids by using the copper nanoparticles Download PDFInfo
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本發明是有關於銅奈米粒子及其製造方法以及使用該銅奈米粒子檢測胺基酸的方法，且特別是有關於一種具有立方結構之銅奈米粒子及其製造方法以及利用上述銅奈米粒子檢測胺基酸的方法。The present invention relates to a copper nanoparticle, a method for producing the same, and a method for detecting an amino acid using the copper nanoparticle, and more particularly to a copper nanoparticle having a cubic structure, a method for producing the same, and the use of the above copper A method of detecting amino acid by rice particles.
茶葉作為一種機能食品而被廣泛的研究，其中含有大量γ-胺基丁酸(γ-aminobutyric acid,GABA)的茶葉被認為具有醫學保健的效果。食物中的α-胺基酸經由不同的發酵路徑，可能會產生β-胺基酸或是γ-胺基酸，例如茶葉在乾燥過程(withering process)中進行厭氧發酵(anaerobic fermentation)，其中α-麩胺酸(α-glutamic acid)會轉化成γ-胺基丁酸，而L-天門冬胺酸(L-aspartic acid)經脫羧反應(decarboxylation)會轉化成β-丙胺酸(β-alanine)。富含γ-胺基丁酸的茶葉其市場價格為一般茶葉的數倍。Tea has been widely studied as a functional food, and tea containing a large amount of γ-aminobutyric acid (GABA) is considered to have a medical health effect. The α-amino acid in the food may produce β-amino acid or γ-amino acid via different fermentation routes, for example, anaerobic fermentation of tea leaves in a withering process, wherein Α-glutamic acid is converted to γ-aminobutyric acid, and L-aspartic acid is converted to β-alanine by decarboxylation (β-alanine) Alanine). The market price of tea rich in γ-aminobutyric acid is several times that of ordinary tea.
目前檢測食品中的α-、β-和γ-胺基酸皆使用光學感測器(photometric detector)並結合高效液相層析法(HPLC,high performance liquid chromatography)或毛細管電泳(CE,capillary electrophoresis)等分離技術以進行檢測。然而，檢驗前需先以衍生試劑對胺基酸預先處理，使之具有螢光或光譜吸收特性才能被檢測出。除光學法外也有使用電化學法來檢測胺基酸，但只侷限於α-胺基酸之測定，例如利用 電沉積法所得約100 nm之球狀(spherical)銅奈米顆粒(CuNPs,copper nanoparticles)可對不同α-胺基酸進行檢測，但此球型銅奈米顆粒無法對β-及γ-胺基酸進行檢測。Currently, α-, β- and γ-amino acids in foods are detected using photometric detectors combined with high performance liquid chromatography (HPLC) or capillary electrophoresis (CE). Separation techniques are used for detection. However, prior to testing, the amino acid should be pretreated with a derivatizing reagent to have a fluorescent or spectral absorption characteristic to be detected. In addition to optical methods, electrochemical methods are also used to detect amino acids, but are limited to the determination of α-amino acids, for example, The spherical gold nanoparticles (CuNPs, about 100 nm) obtained by electrodeposition can detect different α-amino acids, but the spherical copper nanoparticles cannot be used for β- and γ-amines. The base acid is tested.
目前銅奈米粒子的製造方法大都使用電化學沉積法並添加各種選擇性晶格保護劑(selectively crystallographic protective agents)例如十二烷基硫酸鈉(sodium dodecyl sulfate,SDS)或銨離子(NH4 + )、或弱還原劑例如葡萄糖(glucose)、或保護劑例如聚乙二醇辛基苯基醚(p-octyl polyethylene glycol phenylether)等，以生成銅奈米粒子。然而，上述保護劑或還原劑的使用會產生吸附污染的問題，不利於銅奈米粒子表面的電化學活性，進而影響胺基酸的氧化特性。At present, most of the copper nanoparticle production methods use electrochemical deposition and various selective crystallographic protective agents such as sodium dodecyl sulfate (SDS) or ammonium ions (NH 4 +). Or a weak reducing agent such as glucose, or a protective agent such as p-octyl polyethylene glycol phenylether or the like to form copper nanoparticles. However, the use of the above protective agent or reducing agent causes a problem of adsorption contamination, which is disadvantageous to the electrochemical activity of the surface of the copper nanoparticles, thereby affecting the oxidation characteristics of the amino acid.
因此，亟需一種不須添加保護劑或還原劑來製造銅奈米粒子的方法。Therefore, there is a need for a method of producing copper nanoparticles without adding a protective agent or a reducing agent.
本發明提供銅奈米粒子的製造方法，以不須使用保護劑的電化學沉積技術，直接於電極上沉積該銅奈米粒子。The present invention provides a method for producing copper nanoparticles, which deposits the copper nanoparticles directly on the electrodes in an electrochemical deposition technique that does not require the use of a protective agent.
本發明另提供銅奈米粒子，其由本發明之銅奈米粒子的製造方法所製造。The present invention further provides copper nanoparticles which are produced by the method for producing copper nanoparticles of the present invention.
本發明又提供一種胺基酸的檢測方法，包括以電化學氧化法，利用本發明該銅奈米粒子對一含有胺基酸導電溶液進行電化學氧化反應，可蒐集該導電溶液內α-、β-和γ-胺基酸的電化學資訊。The invention further provides a method for detecting an amino acid, comprising: electrochemically oxidizing, using the copper nanoparticle of the invention to electrochemically oxidize a conductive solution containing an amino acid, and collecting α-, Electrochemical information of β- and γ-amino acids.
本發明提出銅奈米粒子的製造方法，包括實施一電化學還原-氧化程序達到一預定次數，得到一預定邊長尺寸的立方體化銅奈米粒子，其中該電化學還原-氧化程序包括以下步驟：以電位循環法電沉積銅奈米粒子，及以電位循環法使該銅奈米粒子產生氧化還原反應。The invention provides a method for manufacturing copper nano particles, comprising performing an electrochemical reduction-oxidation process for a predetermined number of times to obtain cubic copper nanoparticles of a predetermined side length, wherein the electrochemical reduction-oxidation process comprises the following steps : Electrodepositing copper nanoparticles by a potential cycle method, and subjecting the copper nanoparticles to a redox reaction by a potential cycle method.
在本發明一實施例中，該銅奈米粒子的組成包括氧化亞銅及氧化銅。In an embodiment of the invention, the composition of the copper nanoparticle comprises cuprous oxide and copper oxide.
在本發明一實施例中，該銅奈米粒子的組成更包括銅原子。In an embodiment of the invention, the composition of the copper nanoparticle further comprises a copper atom.
在本發明一實施例中，該預定邊長尺寸包括由250 nm至450 nm。In an embodiment of the invention, the predetermined side length dimension comprises from 250 nm to 450 nm.
在本發明一實施例中，以電位循環法電沉積銅奈米粒子的步驟包括：將一工作電極放置於一銅離子溶液中，及以一第一掃描速度對該工作電極施加一第一電位。In an embodiment of the invention, the step of electrodepositing the copper nanoparticles by the potential cycling method comprises: placing a working electrode in a copper ion solution, and applying a first potential to the working electrode at a first scanning speed .
在本發明一實施例中，該銅離子溶液包括硝酸銅溶液、硫酸銅溶液、氯化銅溶液、氰化銅溶液或焦磷酸銅溶液。In an embodiment of the invention, the copper ion solution comprises a copper nitrate solution, a copper sulfate solution, a copper chloride solution, a copper cyanide solution or a copper pyrophosphate solution.
在本發明一實施例中，該銅離子溶液為一硝酸銅溶液，濃度介於4 mM至6 mM之間，pH值介於4.5至5.5之間。In an embodiment of the invention, the copper ion solution is a copper nitrate solution having a concentration between 4 mM and 6 mM and a pH between 4.5 and 5.5.
在本發明一實施例中，該硝酸銅溶液的濃度為5 mM，pH值為4.71。In one embodiment of the invention, the copper nitrate solution has a concentration of 5 mM and a pH of 4.71.
在本發明一實施例中，該第一電位為從+0.05 V至-0.25 V，該第一掃描速度為20 mV/s。In an embodiment of the invention, the first potential is from +0.05 V to -0.25 V, and the first scanning speed is 20 mV/s.
在本發明一實施例中，該工作電極的基材包括網版印刷碳電極、網版印刷金電極、銦錫氧化物、石墨、奈米碳管、鑽石、金或鉑。In an embodiment of the invention, the substrate of the working electrode comprises a screen printing carbon electrode, a screen printing gold electrode, indium tin oxide, graphite, a carbon nanotube, diamond, gold or platinum.
在本發明一實施例中，以電位循環法使該銅奈米粒子產生氧化還原反應的步驟包括：將該工作電極放置於一導電溶液中，及以一第二掃描速度對該工作電極施加一第二電位。In an embodiment of the invention, the step of generating a redox reaction of the copper nanoparticles by a potential cycling method comprises: placing the working electrode in a conductive solution, and applying a working electrode to the working electrode at a second scanning speed. The second potential.
在本發明一實施例中，該導電溶液包括一緩衝溶液。In an embodiment of the invention, the electrically conductive solution comprises a buffer solution.
在本發明一實施例中，該緩衝溶液包括中性緩衝溶液或鹼性緩衝溶液，其中中性緩衝溶液包括2-[三(羥甲基)甲基氨基]-1-乙磺酸(2-[Tris(hydroxymethyl)methylamino]-1-ethanesulfonic acid，TES)、4-(2-羥乙基)-1-哌嗪乙烷磺酸(4-(2-hydroxyethyl)piperazine-1-ethanesulphonic acid，HEPES)或檸檬酸鈉(saline-sodium citrate，SSC)，而鹼性緩衝溶液包括磷酸鹽緩衝溶液、硼酸鹽溶液(borate buffer)或碳酸鹽緩衝溶液。In an embodiment of the invention, the buffer solution comprises a neutral buffer solution or an alkaline buffer solution, wherein the neutral buffer solution comprises 2-[tris(hydroxymethyl)methylamino]-1-ethanesulfonic acid (2- [Tris(hydroxymethyl)methylamino]-1-ethanesulfonic acid, TES), 4-(2-hydroxyethyl)piperazine-1-ethanesulphonic acid, HEPES Or sodium citrate (SSC), and the alkaline buffer solution includes a phosphate buffer solution, a borate buffer or a carbonate buffer solution.
在本發明一實施例中，該導電溶液為一磷酸鹽緩衝溶液，濃度介於9 mM至11 mM之間，pH值介於7.5至9之間。In an embodiment of the invention, the conductive solution is a phosphate buffer solution having a concentration between 9 mM and 11 mM and a pH between 7.5 and 9.
在本發明一實施例中，該磷酸鹽緩衝溶液濃度為10 mM，pH值為8。In one embodiment of the invention, the phosphate buffer solution has a concentration of 10 mM and a pH of 8.
在本發明一實施例中，該第二電位為從-0.3 V至+0.3 V，該第一掃描速度為50 mV/s。In an embodiment of the invention, the second potential is from -0.3 V to +0.3 V, and the first scanning speed is 50 mV/s.
在本發明一實施例中，實施該電化學還原-氧化程序的 次數介於2次至6次之間。In an embodiment of the invention, the electrochemical reduction-oxidation process is performed The number is between 2 and 6 times.
在本發明一實施例中，該胺基酸包括α-胺基酸、β-胺基酸、γ-胺基酸或其組合。In an embodiment of the invention, the amino acid comprises an alpha-amino acid, a beta-amino acid, a gamma-amino acid, or a combination thereof.
在本發明一實施例中，該α-胺基酸包括α-丙胺酸(alanine)、麩胺酸(glutamic acid)、精胺酸(arginine)、脯胺酸(proline)、絲胺酸(serine)、組胺酸(histidine)、異白胺酸(isoleucine)、半胱胺酸(cysteine)、天冬醯胺(asparagine)、天門冬胺酸(aspartic acid)、麩胺醯胺(glutamine)、甘胺酸(glycine)、白胺酸(leucine)、賴胺酸(lysine)、甲硫胺酸(methionine)、***酸(phenylalanine)、蘇胺酸(threonine)、色胺酸(tryptophan)、酪胺酸(tyrosine)與纈胺酸(valine)或其組合，β-胺基酸包括β-丙胺酸，而γ-胺基酸包括γ-胺基丁酸(γ-aminobutyric acid)與γ-胺基羥丁酸(γ-amino hydroxybutyric acid)或其組合。In an embodiment of the invention, the alpha-amino acid comprises a-alanine, glutamic acid, arginine, proline, serine (serine) ), histidine, isoleucine, cysteine, asparagine, aspartic acid, glutamine, Glycine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, cheese Amino acid (tyrosine) and valine or a combination thereof, the β-amino acid includes β-alanine, and the γ-amino acid includes γ-aminobutyric acid and γ-amine. Gamma-hydroxy hydroxybutyric acid or a combination thereof.
基於上述，本發明所提出之銅奈米粒子的製造方法無須使用保護劑且能夠在電極上直接沉積銅奈米粒子。此外，本發明所提出之銅奈米粒子具有立方結構且其邊長尺寸包括300 nm至400 nm。另外，本發明所提出之胺基酸的檢測方法以上述本發明的銅奈米粒子進行檢測，且能對α-胺基酸、β-胺基酸或γ-胺基酸進行免標定式的電化學反應。Based on the above, the method for producing copper nanoparticles according to the present invention does not require the use of a protective agent and can deposit copper nanoparticles directly on the electrodes. Further, the copper nanoparticle proposed by the present invention has a cubic structure and its side length dimension includes 300 nm to 400 nm. In addition, the method for detecting an amino acid proposed by the present invention is detected by the above-mentioned copper nanoparticle of the present invention, and can be subjected to a calibration-free method for α-amino acid, β-amino acid or γ-amino acid. Electrochemical reaction.
為讓本發明之上述特徵和優點能更明顯易懂，下文特舉實施例，並配合所附圖式作詳細說明如下。The above described features and advantages of the present invention will be more apparent from the following description.
圖1繪示本發明一實施例之銅奈米粒子的製造方法的流程圖。首先，以電位循環法(potential cycling)電沉積該銅奈米粒子，參考圖1的步驟S100。將一電化學工作系統(electrochemical workstation)的工作電極置於一含有銅離子溶液中，對工作電極施加一第一電位並以一第一掃描速度進行掃描，以使溶液中的銅離子電沉積於所述工作電極上而形成銅奈米粒子。1 is a flow chart showing a method of manufacturing copper nanoparticles according to an embodiment of the present invention. First, the copper nanoparticles are electrodeposited by potential cycling, referring to step S100 of FIG. A working electrode of an electrochemical workstation is placed in a solution containing copper ions, a first potential is applied to the working electrode and scanned at a first scanning speed to electrodeposit copper ions in the solution. Copper nanoparticles are formed on the working electrode.
電化學工作系統包括三極式系統及二極式系統，其中三極式系統及二極式系統皆包括工作電極及輔助電極。工作電極的基材例如是網版印刷碳電極、網版印刷金電極、銦錫氧化物、碳(包括但不限於石墨及奈米碳管)、鑽石、金或鉑。在本實施例中，工作電極為三極式系統中的一個電極，但本發明不限定於此。在另一實施例中，工作電極可為二極式系統中的一個電極。The electrochemical working system includes a three-pole system and a two-pole system, wherein the three-pole system and the two-pole system both include a working electrode and an auxiliary electrode. The substrate of the working electrode is, for example, a screen printing carbon electrode, a screen printing gold electrode, indium tin oxide, carbon (including but not limited to graphite and carbon nanotubes), diamond, gold or platinum. In the present embodiment, the working electrode is one of the three-pole system, but the present invention is not limited thereto. In another embodiment, the working electrode can be one of the electrodes in a two-pole system.
本實施例的銅離子溶液包括但不限於硝酸銅溶液、硫酸銅溶液、氯化銅溶液、氰化銅溶液或焦磷酸銅溶液。在一實施例中，銅離子溶液為硝酸銅溶液，且其濃度例如是4 mM至6 mM，較佳的是5 mM，且pH值例如是4.5至5.5，較佳的是4.71。另外，施加於工作電極上的第一電位包含該銅離子的擴散限制電位，使得該銅離子可電沉積於工作電極上。舉例來說，當銅離子溶液為硝酸銅溶液且工作電極為網版印刷碳電極時，所施加的第一電位從+0.05 V至-0.25 V，第一掃描速度為20 mV/s，但本發明不限定於 此。熟習技術者可瞭解所施加的第一電位及第一掃描速度會隨著所使用的銅離子溶液及工作電極的材料的不同而改變。The copper ion solution of this embodiment includes, but is not limited to, a copper nitrate solution, a copper sulfate solution, a copper chloride solution, a copper cyanide solution or a copper pyrophosphate solution. In one embodiment, the copper ion solution is a copper nitrate solution, and its concentration is, for example, 4 mM to 6 mM, preferably 5 mM, and the pH is, for example, 4.5 to 5.5, preferably 4.71. Additionally, the first potential applied to the working electrode includes a diffusion confinement potential of the copper ion such that the copper ion can be electrodeposited on the working electrode. For example, when the copper ion solution is a copper nitrate solution and the working electrode is a screen printing carbon electrode, the first potential applied is from +0.05 V to -0.25 V, and the first scanning speed is 20 mV/s, but The invention is not limited to this. Those skilled in the art will appreciate that the applied first potential and first scanning speed will vary depending on the copper ion solution used and the material of the working electrode.
上述銅奈米粒子的組成(composition)包括銅原子(Cu0 )、氧化亞銅(CuO2 )、氧化銅(CuO)或其組合。在一實施例中，銅奈米粒子的組成主要包括氧化亞銅及氧化銅，其中又以氧化亞銅居多，這是因為在步驟S100中，大部分的銅離子(Cu2+ )被還原成氧化亞銅(Cu2 O)而沉積於工作電極上，而一部分的銅離子形成不溶於水的氧化銅而沉積於工作電極上，但本發明之銅奈米粒子的組成不限定於此。在另一實施例中，銅奈米粒子的組成還包括銅原子。The composition of the above copper nanoparticles includes copper atoms (Cu 0 ), cuprous oxide (CuO 2 ), copper oxide (CuO), or a combination thereof. In one embodiment, the composition of the copper nanoparticles mainly comprises cuprous oxide and copper oxide, wherein copper oxide is mostly present, because in step S100, most of the copper ions (Cu 2+ ) are reduced to Cuprous oxide (Cu 2 O) is deposited on the working electrode, and a part of the copper ions form water-insoluble copper oxide and deposit on the working electrode, but the composition of the copper nanoparticle of the present invention is not limited thereto. In another embodiment, the composition of the copper nanoparticle further comprises a copper atom.
接著下一個步驟，以電位循環法使銅奈米粒子產生氧化還原反應，參考圖1之步驟S102。將已沉積有銅奈米粒子的工作電極更換置於一導電溶液中，對工作電極施加一第二電位並以一第二掃描速度進行掃描，以使工作電極上的銅奈米粒子的金屬價數發生改變。值得說明的是，對工作電極所施加的第二電位可使得已沉積的銅奈米粒子進行氧化及還原反應，但卻無法完全使其還原成銅原子，並且熟習技術者應理解所施加的第二電位可隨所使用的工作電極材料、溶液條件及銅奈米粒子材料的不同而改變。Next, in the next step, the copper nanoparticles are subjected to a redox reaction by a potential cycle method, referring to step S102 of FIG. The working electrode which has deposited the copper nanoparticle is replaced in a conductive solution, a second potential is applied to the working electrode and scanned at a second scanning speed to make the metal price of the copper nanoparticle on the working electrode The number has changed. It is worth noting that the second potential applied to the working electrode can cause the deposited copper nanoparticles to undergo oxidation and reduction reactions, but cannot completely reduce them to copper atoms, and the skilled person should understand the applied The two potentials can vary depending on the working electrode material used, the solution conditions, and the copper nanoparticle material.
本實施例之導電溶液是以磷酸鹽緩衝溶液(phosphate buffered saline)為例進行說明，但本發明不限定於此。步驟S102中的導電溶液例如是緩衝溶液，緩衝溶液包括中性緩 衝溶液或鹼性緩衝溶液，其中中性緩衝溶液包括2-[三(羥甲基)甲基氨基]-1-乙磺酸(2-[Tris(hydroxymethyl)methylamino]-1-ethanesulfonic acid，TES)、4-(2-羥乙基)-1-哌嗪乙烷磺酸(4-(2-hydroxyethyl)piperazine-1-ethanesulphonic acid，HEPES)或檸檬酸鈉(saline-sodium citrate，SSC)，而鹼性緩衝溶液包括磷酸鹽緩衝溶液、硼酸鹽溶液(borate buffer)或碳酸鹽緩衝溶液，但本發明並不限於此。The conductive solution of the present embodiment is described by taking phosphate buffered saline as an example, but the present invention is not limited thereto. The conductive solution in step S102 is, for example, a buffer solution, and the buffer solution includes a neutral buffer. A flushing solution or an alkaline buffer solution, wherein the neutral buffer solution comprises 2-[Tris(hydroxymethyl)methylamino]-1-ethanesulfonic acid, TES , 4-(2-hydroxyethyl)piperazine-1-ethanesulphonic acid (HEPES) or sodium-sodium citrate (SSC), The alkaline buffer solution includes a phosphate buffer solution, a borate buffer or a carbonate buffer solution, but the invention is not limited thereto.
在一實施例中，上述導電溶液為磷酸鹽緩衝溶液，其濃度例如是9 mM至11 mM，較佳的是10 mM，且pH值例如是7.5至9，較佳的是8。另外，施加於工作電極上的第二電位包括銅的氧化還原電位。舉例來說，當上述導電溶液為磷酸緩衝溶液，且工作電極為網版印刷碳電極時，所施加的第二電位從-0.3 V至+0.3 V，第二掃描速度為50 mV/s，但本發明不限定於此，熟習技術者可瞭解所施加的第二電位及第二掃描速度會隨所使用的工作電極材料、溶液條件及銅奈米粒子組成的不同而改變。In one embodiment, the above conductive solution is a phosphate buffer solution having a concentration of, for example, 9 mM to 11 mM, preferably 10 mM, and a pH of, for example, 7.5 to 9, preferably 8. Additionally, the second potential applied to the working electrode includes the redox potential of copper. For example, when the conductive solution is a phosphate buffer solution and the working electrode is a screen printing carbon electrode, the applied second potential is from -0.3 V to +0.3 V, and the second scanning speed is 50 mV/s, but The present invention is not limited thereto, and those skilled in the art will appreciate that the applied second potential and the second scanning speed vary depending on the working electrode material used, the solution conditions, and the composition of the copper nanoparticles.
在此須說明的是，步驟S102會對於步驟100中所沉積的銅奈米粒子的表面結晶狀態進行修飾(modified)，使得後續再沉積的銅奈米粒子的晶格在<111>方向的成長速率大於<100>方向，進而使大部分的銅奈米粒子形成立方體結構。It should be noted that step S102 will modify the surface crystal state of the copper nanoparticles deposited in step 100, so that the crystal lattice of the subsequently redeposited copper nanoparticles grows in the <111> direction. The rate is greater than the <100> direction, which in turn causes most of the copper nanoparticles to form a cubic structure.
若後續重複實施步驟S100及步驟S102的電化學還原-氧化程序，立方體化的銅奈米粒子可以持續成長。本發明 之銅奈米粒子的製造方法包括以電位循環法實施步驟S100及步驟S102的電化學還原-氧化程序至少一次。然而，熟習技術者可視銅奈米粒子在應用上所需要的尺寸，而決定實施步驟S100及步驟S102的次數，使其達到一預定的尺寸。If the electrochemical reduction-oxidation procedure of step S100 and step S102 is subsequently repeated, the cubic copper nanoparticles can continue to grow. this invention The method for producing copper nanoparticles includes performing the electrochemical reduction-oxidation process of step S100 and step S102 at least once by a potential cycle method. However, the skilled person can determine the number of steps S100 and S102 to be performed to a predetermined size, depending on the size required for the application of the copper nanoparticles.
在一實施例中，依序進行步驟S100及步驟S102一次，所形成的立方體化的銅奈米粒子佔整體銅奈米粒子的比例為95%，而其邊長尺寸分布在150 nm至300 nm之間。在另一實施例中，實施步驟S100及步驟S102兩次，所形成的立方體化的銅奈米粒子佔整體銅奈米粒子的比例為90%，而其邊長尺寸分布在250 nm至400 nm之間。在又一實施例中，實施步驟S100及步驟S102六次，所形成的立方體化的銅奈米粒子佔整體銅奈米粒子的比例為87%，而其邊長尺寸分布在250 nm至450 nm之間。In one embodiment, step S100 and step S102 are performed in sequence, and the formed cubic nano-particles occupy 95% of the total copper nanoparticles, and the side lengths are distributed between 150 nm and 300 nm. between. In another embodiment, step S100 and step S102 are performed twice, and the formed cubic nano-particles occupy 90% of the total copper nanoparticles, and the side lengths are distributed between 250 nm and 400 nm. between. In another embodiment, step S100 and step S102 are performed six times, and the formed cubic nano-particles occupy 87% of the total copper nanoparticles, and the side lengths are distributed between 250 nm and 450 nm. between.
本發明上述的方法所製造的銅奈米粒子，具有尺寸集中且密度較高的立方體化銅奈米粒子，而不會造成大量非立方體化(non-cubed)銅奈米粒子的聚集。The copper nanoparticles produced by the above method of the present invention have cubic copper nanoparticles having a large concentration and a high density without causing aggregation of a large number of non-cubed copper nanoparticles.
本發明上述的方法所製造的銅奈米粒子可以對胺基酸(包括但不限於α-、β-及γ-胺基酸)產生電化學氧化反應，可將其應用於檢測食品中的胺基酸。而此胺基酸的檢測方法如以下實施例中所述。The copper nanoparticles produced by the above method of the present invention can electrochemically oxidize an amino acid (including but not limited to α-, β- and γ-amino acids), which can be applied to the detection of amines in foods. Base acid. The method for detecting the amino acid is as described in the following examples.
圖2繪示本發明一實施例之胺基酸的檢測方法的流程圖。首先，以一電化學氧化法，利用銅奈米粒子對一導電溶液進行電化學氧化反應，參考圖2的步驟200。將前述 實施例中沉積有立方體化銅奈米粒子的工作電極(網版印刷碳電極)置於一導電溶液中，對工作電極施加一工作電位，以進行電化學氧化反應。本實施例之工作電極是以網版印刷碳電極為例進行說明，但本發明不限定於此，本實施例所採用的工作電極基材會隨著前述實施例製造銅奈米粒子的工作電極基材而改變。因此，本發明的工作電極的基材包括但不限於網版印刷碳電極、網版印刷金電極、銦錫氧化物、碳(包括但不限於石墨及奈米碳管)、鑽石、金或鉑。2 is a flow chart showing a method for detecting an amino acid according to an embodiment of the present invention. First, an electrochemical oxidation reaction is performed on a conductive solution by copper oxide particles by an electrochemical oxidation method, referring to step 200 of FIG. Will be mentioned above In the embodiment, a working electrode (screen printing carbon electrode) deposited with cubic copper nanoparticles is placed in a conductive solution, and an operating potential is applied to the working electrode to perform an electrochemical oxidation reaction. The working electrode of the present embodiment is described by taking a screen printing carbon electrode as an example. However, the present invention is not limited thereto, and the working electrode substrate used in the embodiment may be a working electrode for manufacturing copper nano particles according to the foregoing embodiment. Changed by the substrate. Thus, the substrate of the working electrode of the present invention includes, but is not limited to, screen printing carbon electrodes, screen printing gold electrodes, indium tin oxide, carbon (including but not limited to graphite and carbon nanotubes), diamond, gold or platinum. .
本實施例之導電溶液是以磷酸鹽緩衝溶液(phosphate buffered saline)為例進行說明，但本發明不限定於此。步驟S102中的導電溶液例如是緩衝溶液，緩衝溶液包括中性緩衝溶液或鹼性緩衝溶液，其中中性緩衝溶液包括TES、HEPES或SSC，而鹼性緩衝溶液包括磷酸鹽緩衝溶液、硼酸鹽溶液或碳酸鹽緩衝溶液，但本發明並不限於此。在一實施例中，上述導電溶液為磷酸鹽緩衝溶液，其濃度例如是9 mM至11 mM，較佳的是10 mM，pH值例如是7.5至9，較佳的是8。The conductive solution of the present embodiment is described by taking phosphate buffered saline as an example, but the present invention is not limited thereto. The conductive solution in step S102 is, for example, a buffer solution, and the buffer solution includes a neutral buffer solution or an alkaline buffer solution, wherein the neutral buffer solution includes TES, HEPES or SSC, and the alkaline buffer solution includes a phosphate buffer solution and a borate solution. Or a carbonate buffer solution, but the invention is not limited thereto. In one embodiment, the above conductive solution is a phosphate buffer solution having a concentration of, for example, 9 mM to 11 mM, preferably 10 mM, and a pH of, for example, 7.5 to 9, preferably 8.
本發明的電化學氧化法包括但不限於循環伏安法(cyclic voltammetry)與流動式注入分析法(flow injection analysis,FIA)。The electrochemical oxidation method of the present invention includes, but is not limited to, cyclic voltammetry and flow injection analysis (FIA).
在一實施例中，該電化學氧化法是以循環伏安法為例進行說明，其中將前述實施例中沉積有立方體化銅奈米粒子的網版印刷碳電極(工作電極)置於磷酸鹽緩衝溶液(10 mM,pH 8)中，之後對工作電極施加一工作電位，所施加的工作電位從-0.3 V至+0.3 V，掃描速度為50 mV/s，但本發明不限定於此，熟習技術者可瞭解所施加的工作電位及掃描速度會隨所使用的工作電極材料、溶液條件及銅奈米粒子組成的不同而改變。In one embodiment, the electrochemical oxidation method is exemplified by cyclic voltammetry in which a screen printing carbon electrode (working electrode) in which cubic copper nanoparticles are deposited in the foregoing embodiment is placed in a phosphate. Buffer solution (10 In mM, pH 8), a working potential is applied to the working electrode, the applied working potential is from -0.3 V to +0.3 V, and the scanning speed is 50 mV/s, but the present invention is not limited thereto, and those skilled in the art may Knowing the applied operating potential and scanning speed will vary depending on the working electrode material used, the solution conditions, and the composition of the copper nanoparticles.
在另一實施例中，該電化學氧化法是以流動式注入分析法為例進行說明，其中將前述實施例中沉積有立方體化銅奈米粒子的網版印刷碳電極(工作電極)置於磷酸鹽緩衝溶液(10 mM,pH 8)中，之後對工作電極施加一工作電位，所施加的工作電位為固定電位+0.18V，流速為50 rpm，但本發明不限定於此，熟習技術者可瞭解所施加的工作電位及流速會隨所使用的工作電極材料、溶液條件及銅奈米粒子組成的不同而改變。In another embodiment, the electrochemical oxidation method is exemplified by a flow injection analysis method in which a screen printing carbon electrode (working electrode) in which cubic copper nanoparticles are deposited in the foregoing embodiment is placed. In a phosphate buffer solution (10 mM, pH 8), a working potential is applied to the working electrode, and the applied working potential is a fixed potential + 0.18 V, and the flow rate is 50 rpm, but the present invention is not limited thereto, and the skilled person It can be appreciated that the applied operating potential and flow rate will vary depending on the working electrode material used, the solution conditions, and the composition of the copper nanoparticles.
接著，蒐集導電溶液的電化學資訊，以判斷導電溶液中是否含有胺基酸，參考圖2的步驟202。在本發明實施例中，步驟202的電化學資訊會隨著步驟200採用的電化學氧化法的不同而有不同的呈現方式，電化學資訊例如是響應電流(response current)。Next, the electrochemical information of the conductive solution is collected to determine whether the conductive solution contains an amino acid, as described in step 202 of FIG. In the embodiment of the present invention, the electrochemical information of step 202 may have different representations depending on the electrochemical oxidation method employed in step 200, and the electrochemical information is, for example, a response current.
在一實施例中，當電化學資訊中的值大於一設定值時，則可判斷溶液中有胺基酸存在。胺基酸包括α-胺基酸、β-胺基酸、γ-胺基酸或其組合，其中α-胺基酸包括但不限於α-丙胺酸(alanine)、麩胺酸(glutamic acid)、精胺酸(arginine)、脯胺酸(proline)、絲胺酸(serine)、組胺酸(histidine)、異白胺酸(isoleucine)、半胱胺酸(cysteine)、天 冬醯胺(asparagine)、天門冬胺酸(aspartic acid)、麩胺醯胺(glutamine)、甘胺酸(glycine)、白胺酸(leucine)、賴胺酸(lysine)、甲硫胺酸(methionine)、***酸(phenylalanine)、蘇胺酸(threonine)、色胺酸(tryptophan)、酪胺酸(tyrosine)與纈胺酸(valine)或其組合，β-胺基酸例如是β-丙胺酸，而γ-胺基酸例如是γ-胺基丁酸(γ-aminobutyric acid)、γ-胺基羥丁酸(γ-amino hydroxybutyric acid)或其組合。In one embodiment, when the value in the electrochemical information is greater than a set value, it can be determined that an amino acid is present in the solution. The amino acid includes an α-amino acid, a β-amino acid, a γ-amino acid or a combination thereof, wherein the α-amino acid includes, but is not limited to, α-alanine, glutamic acid, and glutamic acid. , arginine, proline, serine, histidine, isoleucine, cysteine, cysteine Asparagine, aspartic acid, glutamine, glycine, leucine, lysine, methionine (asparagine) Methionine), phenylalanine, threonine, tryptophan, tyrosine and valine or combinations thereof, β-amino acid such as β-propylamine The acid, and the γ-amino acid is, for example, γ-aminobutyric acid, γ-amino hydroxybutyric acid or a combination thereof.
在一實施例中，當立方體化的銅奈米粒子的邊長尺寸介於250 nm至450 nm之間時，其對於胺基酸有較佳的電化學氧化特性，更佳的邊長尺寸是介於300 nm至400 nm之間。In one embodiment, when the side length of the cubic copper nanoparticles is between 250 nm and 450 nm, it has better electrochemical oxidation characteristics for the amino acid, and the preferred side length is Between 300 nm and 400 nm.
以下實驗例詳細說明了本發明之銅奈米粒子及其製造方法，以及利用上述銅奈米粒子對胺基酸進行電化學氧化的實驗結果，從而允許普通熟習此項技術者實踐本發明。然而，下列實驗例並非用以限制本發明，普通熟習此項技術者可鑒於以下詳細實例說明瞭解本發明之原理、其操作參數及其他明顯的修改。The following experimental examples illustrate in detail the copper nanoparticles of the present invention and a method for producing the same, and experimental results of electrochemical oxidation of an amino acid using the above copper nanoparticles, thereby allowing the person skilled in the art to practice the present invention. However, the following experimental examples are not intended to limit the invention, and those skilled in the art can understand the principles of the invention, its operational parameters, and other obvious modifications.
以三極式系統進行銅奈米粒子(copper nanoparticle,CuNP)的電沉積作用。Electrodeposition of copper nanoparticle (CuNP) was carried out in a three-pole system.
所使用的電極、儀器及實驗方法如下：The electrodes, instruments and experimental methods used are as follows:
電化學工作系統(CH Instruments,Austin,TX,USA)Electrochemical Operating System (CH Instruments, Austin, TX, USA)
工作電極：可拋棄式網版印刷碳電極(SF-100，Zensor Research & Development)，其工作面積為1.8 mm2 Working electrode: Disposable screen printing carbon electrode (SF-100, Zensor Research & Development) with a working area of 1.8 mm 2
參考電極：銀/氯化銀(Ag/AgCl)Reference electrode: silver / silver chloride (Ag / AgCl)
輔助電極：鉑絲(Pt)Auxiliary electrode: platinum wire (Pt)
儀器：恆電位儀(CHI7105,CH Instruments)Instrument: Potentiostat (CHI7105, CH Instruments)
實驗方法：首先，以恆電位儀在鍍液中施加+2.0 V的電位30秒，以活化網版印刷碳電極表面使其產生親水基。隨後，將上述電極浸泡至以去離子水配置的5 mM之Cu(NO3 )2 溶液(pH值為4.71)中，利用恆電位儀以20 mV/s的掃描速度，從電位+0.05 V到-0.25 V對網版印刷碳電極進行掃瞄不同圈數，例如是6圈，而進行沉積銅奈米粒子。在本文中，將上述沉積銅奈米粒子的方法定義為直接還原法(directly reductive method，下文中以DR法表示)。Experimental method: First, a potential of +2.0 V was applied to the plating solution for 30 seconds with a potentiostat to activate the screen printing carbon electrode surface to generate a hydrophilic group. Subsequently, the above electrode was immersed in a 5 mM Cu(NO 3 ) 2 solution (pH 4.71) in deionized water, using a potentiostat at a scanning speed of 20 mV/s from a potential of +0.05 V to -0.25 V scans the screen printing carbon electrode for different turns, for example 6 turns, and deposits copper nanoparticles. Herein, the above method of depositing copper nanoparticles is defined as a direct reductive method (hereinafter referred to as a DR method).
圖3為以直接還原法沉積銅奈米粒子之第1圈到第6圈的循環伏安圖。請參照圖3，在掃描第1圈時，產生較大的還原電流，其還原波峰電位為-0.22 V，這較大的過電位(overpotential)可能是由Cu2+ 於網版印刷碳電極上進行異質性電子轉移(heterogeneous electron transfer)所致。而在掃描第2圈時，所產生的還原波峰電位上升至-0.15 V，此表示過電位減少，且可能是由Cu2+ 與於掃描第1圈時已沉積在電極上的銅奈米粒子進行同質性電子轉移(homogeneous electron transfer)的沉積作用所致。此外，在掃描第3圈之後，所產生的還原波峰電位更上升至-0.10 V，且隨後的掃瞄圈數所產生的還原波峰電位不再變化，此表示沉積Cu2+ 的過電位至第3圈後便更為降低並趨於穩定，這是由於Cu2+ 可在已沉積的銅奈米粒子上穩定地繼續 沉積。Figure 3 is a cyclic voltammogram of the first to sixth turns of the copper nanoparticles deposited by the direct reduction method. Referring to FIG. 3, when the first turn is scanned, a large reduction current is generated, and the reduction peak potential is -0.22 V. This large overpotential may be caused by Cu 2+ on the screen printing carbon electrode. Caused by heterogeneous electron transfer. On the second lap of scanning, the resulting reduction peak potential rises to -0.15 V, which means that the overpotential is reduced, and may be Cu 2+ and copper nanoparticles deposited on the electrode at the first turn of the scan. It is caused by the deposition of homogenous electron transfer. In addition, after the third lap of scanning, the resulting reduction peak potential rises further to -0.10 V, and the reduction peak potential generated by the subsequent number of scan turns no longer changes, which indicates that the overpotential of Cu 2+ is deposited to the After 3 turns, it is more reduced and tends to be stable, because Cu 2+ can continue to deposit stably on the deposited copper nanoparticles.
除了以下述的實驗步驟來進行電沉積銅奈米粒子外，以與實驗例1中所使用的相同系統、電極及儀器來進行實驗。The experiment was carried out in the same system, electrode and apparatus as used in Experimental Example 1, except that the copper nanoparticles were electrodeposited in the following experimental procedure.
在本文中，將以下所進行的實驗步驟定義為先還原後氧化法(reductive and oxidative method，下文中RO法表示)。Herein, the experimental steps performed below are defined as a reductive and oxidative method (hereinafter referred to as the RO method).
實驗步驟如下：The experimental steps are as follows:
首先，進行直接還原法的步驟，以20 mV/s的掃描速度，從電位+0.05 V到-0.25 V掃瞄1圈(在先還原後氧化法中，將此步驟定義為還原步驟)。繼之，將進行還原步驟1圈而沉積有銅奈米粒子的網版印刷碳電極放置到10 mM的磷酸鹽緩衝溶液(phosphate buffered saline，PBS，pH值為8)中，並以50 mV/s的掃描速度，從電位-0.3 V到+0.3 V進行掃描1圈(在先還原後氧化法中，將此步驟定義為氧化步驟)。之後，將上述還原步驟及氧化步驟當作一個循環(意即，進行還原步驟1圈接著進行氧化步驟步驟1圈為以先還原後氧化法進行沉積1圈)，並反覆進行此循環至例如是6圈，以得到圖4a及圖4b。First, the direct reduction method was carried out, and scanning was performed once at a potential of +0.05 V to -0.25 V at a scanning speed of 20 mV/s (this step is defined as a reduction step in the prior reduction oxidation method). Next, the screen printing carbon electrode in which the copper nanoparticle was deposited was subjected to a reduction step and placed in a 10 mM phosphate buffered saline (PBS, pH 8) at 50 mV/ The scanning speed of s is scanned one turn from the potential -0.3 V to +0.3 V (this step is defined as the oxidation step in the prior reduction oxidation method). Thereafter, the above-mentioned reduction step and oxidation step are regarded as one cycle (that is, one cycle of the reduction step is performed followed by one oxidation step of the oxidation step is performed for one cycle after the first reduction and then oxidation), and the cycle is repeated to, for example, 6 turns to get Figure 4a and Figure 4b.
圖4a為以先還原後氧化法沉積銅奈米粒子之第1圈到第6圈還原沉積的循環伏安圖。圖4b為對應圖3a中之第1圈到第5圈之進行氧化步驟的循環伏安圖。請參照圖4a，可發現以還原後氧化法進行銅奈米粒子電沉積時，在 任一掃描圈數中，所產生的電流與還原波峰電位並無顯著改變。接著，請參照圖4b，在電位為-0.065 V時，產生使Cu0 氧化成Cu1+ 的氧化波Pa1 ，而當電位增加到+0.18 V時，產生使Cu1+ 氧化成Cu2+ 的氧化波Pa2 。之後，當電位反折至-0.16 V時，產生使Cu2+ 還原成Cu1+ 的還原波Pc1 ，而當電位降至-0.24 V時，產生使Cu1+ 還原成Cu0 的還原波Pc2 。然而，由於-0.3 V的電位未能將所有的Cu1+ 還原成Cu 0 ，故還原波Pc2 的還原電流遠小於還原波Pc1 ，進而使得沉積在工作電極上的銅奈米粒子表面以氧化態(Cu2 O及CuO)的形式存在。Figure 4a is a cyclic voltammogram of the reduced deposition from the first to sixth passes of the copper nanoparticles deposited by the first reduction and subsequent oxidation. Figure 4b is a cyclic voltammogram of the oxidation step corresponding to the first to fifth turns of Figure 3a. Referring to FIG. 4a, it can be found that when the copper nanoparticles are electrodeposited by the post-reduction oxidation method, the generated current and the reduction peak potential are not significantly changed in any of the scanning cycles. Next, referring to FIG. 4b, when the potential is -0.065 V, an oxidation wave P a1 which oxidizes Cu 0 to Cu 1+ is generated, and when the potential is increased to +0.18 V, Cu 1+ is oxidized to Cu 2+ . Oxidation wave P a2 . Thereafter, when the potential is reversed to -0.16 V, a reduction wave P c1 which reduces Cu 2+ to Cu 1+ is generated, and when the potential is lowered to -0.24 V, a reduction wave which reduces Cu 1+ to Cu 0 is generated. P c2 . However, since the potential of -0.3 V fails to reduce all Cu 1+ to C u 0 , the reduction current of the reduction wave P c2 is much smaller than the reduction wave P c1 , thereby causing the surface of the copper nanoparticles deposited on the working electrode. It exists in the form of oxidation (Cu 2 O and CuO).
因此，圖4a中所顯示之不同掃瞄圈數的電流與還原波峰電位無顯著改變的原因，可能是由於在每一次銅奈米粒子還原沉積後的氧化步驟，使得溶液擴散回復，且使每一次的沉積可進行瞬間成核反應所致。Therefore, the reason why the current and the reduction peak potential of the different scanning laps shown in FIG. 4a are not significantly changed may be due to the oxidation step after each copper nanoparticle reduction deposition, so that the solution diffusion is restored, and each One deposition can be caused by an instantaneous nucleation reaction.
在進行實驗例1及實驗例2取得沉積在工作電極上的銅奈米粒子後，接著進行以下檢測，以探討利用直接還原法及先還原後氧化法並不同掃瞄圈數下所沉積的銅奈米粒子的結構及電化學特性以及應用。After the copper nanoparticles deposited on the working electrode were obtained in Experimental Example 1 and Experimental Example 2, the following tests were carried out to investigate the copper deposited by the direct reduction method and the first reduction after oxidation method and different scanning cycles. The structure and electrochemical properties of nanoparticles and their applications.
(一)銅奈米粒子的結構型態(1) The structural form of copper nanoparticles
以掃描式電子顯微鏡(Scanning Electron Microscope，SEM)對利用直接還原法及先還原後氧化法並不同掃瞄圈數下所形成之銅奈米粒子進行結構型態的觀測。The structure of the copper nanoparticles formed by the direct reduction method and the first reduction and oxidation method and different scanning laps was observed by a scanning electron microscope (SEM).
所使用的儀器及操作步驟如下：The instruments and operating procedures used are as follows:
儀器：掃描式電子顯微鏡(JSM-7401F，JEOL)Instrument: Scanning Electron Microscope (JSM-7401F, JEOL)
操作步驟：首先，將各試片鍍白金膜30秒，以增加導電性。接著，設定參數，以加速電壓3 kV、工作距離(working distance，WD)3 mm下進行拍攝，而每張選取面積為7 μm×8 μm並選取3張。然後，根據所選取的掃描式電子顯微鏡圖計算銅奈米粒子的粒徑大小以及立方結構銅奈米粒子佔整體銅奈米粒子的比率。Operation steps: First, each test piece was plated with a platinum film for 30 seconds to increase conductivity. Next, set the parameters and shoot at an acceleration voltage of 3 kV and a working distance (WD) of 3 mm, and each selected area is 7 μm × 8 μm and three are selected. Then, the particle size of the copper nanoparticles and the ratio of the cubic copper nanoparticles to the overall copper nanoparticles are calculated according to the selected scanning electron microscope image.
圖5a到圖5d為進行不同沉積步驟時之銅奈米粒子的掃描式電子顯微鏡圖，其中比例尺為1 μm。圖5e為具有立方結構之銅奈米粒子的粒徑分佈圖。另外，根據所選取的圖5a到圖5d，立方結構之銅奈米粒子所佔比率的計算結果如下表1所示。Figures 5a to 5d are scanning electron micrographs of copper nanoparticles in different deposition steps, with a scale of 1 μm. Fig. 5e is a particle size distribution diagram of copper nanoparticles having a cubic structure. Further, according to the selected FIG. 5a to FIG. 5d, the calculation results of the ratio of the copper nanoparticles of the cubic structure are shown in Table 1 below.
請同時參照圖5a、圖5e及表1，在使用直接還原法進行1圈沉積(本文中以DR 1表示)時，生成之立方結構銅奈米粒子佔整體銅奈米粒子的比率為95%。這表示此時大部分的銅奈米粒子皆為立方結構，且粒徑的尺寸分佈為150 nm至299 nm。接著，請同時參照圖5b、圖5e及表1，當使用直接還原法進行6圈沉積(本文中以DR 6表示)時，立方結構銅奈米粒子的比率則大幅降至42%，且銅奈 米粒子的粒徑尺寸分佈為300 nm至750 nm，而其餘大部分的銅奈米粒子呈現類似球狀之多晶體結構。這表示以直接還原法連續進行沉積會造成銅奈米粒子彼此聚集，進而產生較大的多晶體結構。Referring to FIG. 5a, FIG. 5e and Table 1, when the direct reduction method is used for one-time deposition (indicated by DR 1 herein), the ratio of the generated cubic nano-particles to the total copper nanoparticles is 95%. . This means that most of the copper nanoparticles are cubic in shape at this time, and the size distribution of the particle size is 150 nm to 299 nm. Next, please refer to FIG. 5b, FIG. 5e and Table 1. When the direct reduction method is used for 6-turn deposition (represented by DR 6 herein), the ratio of cubic copper nanoparticles is greatly reduced to 42%, and copper. Nai The particle size distribution of the rice particles ranges from 300 nm to 750 nm, while most of the other copper nanoparticles exhibit a spherical-like polycrystalline structure. This means that continuous deposition by direct reduction causes the copper nanoparticles to aggregate with each other, resulting in a larger polycrystalline structure.
另外，請同時參照圖5c、圖5e及表1，當使用先還原後氧化法進行2圈沉積(本文中以RO 2表示)時，生成之立方結構銅奈米粒子佔整體銅奈米粒子的比率為90%，且粒徑的尺寸分佈為250 nm至400 nm。接著，請同時參照圖4d、圖4e及表1，當使用先還原後氧化法進行6圈沉積(本文中以RO 6表示)時，生成之立方結構銅奈米粒子佔整體銅奈米粒子的比率為87%，且粒徑的尺寸分佈為250 nm至450 nm。In addition, please refer to FIG. 5c, FIG. 5e and Table 1 simultaneously, when two-turn deposition (indicated by RO 2 in this example) is performed by the first reduction and oxidation method, the generated cubic copper nanoparticles occupy the entire copper nanoparticle. The ratio is 90% and the particle size distribution is from 250 nm to 400 nm. Next, please refer to FIG. 4d, FIG. 4e and Table 1 at the same time. When 6 cycles of deposition (indicated by RO 6 in this example) are performed by the first reduction and oxidation method, the generated cubic copper nanoparticles occupy the entire copper nanoparticle. The ratio is 87% and the particle size distribution is from 250 nm to 450 nm.
基於上述，可知採用先還原後氧化法進行銅奈米粒子沉積不會造成大量銅奈米粒子聚集，並且可僅以電位來控制銅奈米粒子的表面狀態，使<111>方向的成長速率大於<100>，而逐步產生不同粒徑尺寸且集中又密度高的立方結構銅奈米粒子。Based on the above, it can be seen that the deposition of copper nanoparticles by the first reduction and oxidation method does not cause a large amount of copper nanoparticles to aggregate, and the surface state of the copper nanoparticles can be controlled only by the potential, so that the growth rate in the <111> direction is greater than <100>, and gradually produce cubic copper nanoparticles of different particle size and concentration and high density.
(二)銅奈米粒子的晶格結構(2) The lattice structure of copper nanoparticles
以X光繞射法(X-ray diffraction)對利用直接還原法及先還原後氧化法並不同掃瞄圈數下所形成之銅奈米粒子進行晶格結構的量測。The crystal lattice structure of the copper nanoparticles formed by the direct reduction method and the first reduction and oxidation method and different scanning cycles was measured by X-ray diffraction.
所使用的儀器及量測參數如下：The instruments and measurement parameters used are as follows:
儀器：X-光繞射分析儀(X-ray Diffractometer，XRD)(型號為X’Pert Pro MRD，由PANalytical公司製造)Instrument: X-ray Diffractometer (XRD) (model X’Pert Pro MRD, manufactured by PANalytical)
量測參數：以2θ低掠角繞射(θ=1°)，且掃描速度 為3°/min的方式進行量測。Measurement parameters: diffraction at a low sweep angle of 2θ (θ = 1°), and scanning speed The measurement was carried out in a manner of 3°/min.
圖6為進行不同沉積步驟所得的沉積有銅奈米粒子之網版印刷碳電極的XRD 2θ頻譜圖，其中線1為使用直接還原法進行1圈之網版印刷碳電極的XRD 2θ頻譜圖、線2為使用直接還原法進行6圈之網版印刷碳電極的XRD 2θ頻譜圖、線3為使用先還原後氧化法進行2圈之網版印刷碳電極的XRD 2θ頻譜圖以及線4為使用先還原後氧化法進行6圈之網版印刷碳電極的XRD 2θ頻譜圖。另外，圖6中，在29.58°、36.44°與42.33°處的波鋒分別代表Cu2 O(110)、Cu2 O(111)與Cu2 O(200)(JCPDS 01-070-3039)，而在33°處的波峰代表CuO(110)(JCPDS 00-077-0199)；其他波峰則為網版印刷碳電極之碳基材的晶格繞射波峰。6 is an XRD 2θ spectrum diagram of a screen printing carbon electrode deposited with copper nanoparticles obtained by performing different deposition steps, wherein line 1 is an XRD 2θ spectrum of a screen printing carbon electrode using a direct reduction method; Line 2 is the XRD 2θ spectrum of the 6-turn screen printing carbon electrode using the direct reduction method, line 3 is the XRD 2θ spectrum of the screen printing carbon electrode using the first reduction and oxidation method, and line 4 is used. The XRD 2θ spectrum of the 6-turn screen printing carbon electrode was firstly oxidized and then oxidized. In addition, in Fig. 6, the wave fronts at 29.58°, 36.44° and 42.33° respectively represent Cu 2 O(110), Cu 2 O(111) and Cu 2 O(200) (JCPDS 01-070-3039), The peak at 33° represents CuO(110) (JCPDS 00-077-0199); the other peaks are the lattice diffraction peaks of the carbon substrate of the screen printing carbon electrode.
請參照圖6，可發現不論是使用直接還原法還是先還原後氧化法進行不同圈數的沉積，所生成的銅奈米粒子的成分皆主要以Cu2 O及CuO為主。Referring to Fig. 6, it can be found that the composition of the copper nanoparticles is mainly Cu 2 O and CuO, regardless of whether the direct reduction method or the first reduction oxidation method is used for deposition of different turns.
接著，根據圖6中的波峰強度，比較進行不同沉積步驟所得之銅奈米粒子的晶格面強度比率的關係，如下表2所示。Next, the relationship of the lattice surface intensity ratios of the copper nanoparticles obtained by the different deposition steps was compared based on the peak intensities in FIG. 6, as shown in Table 2 below.
請參照表2，可發現使用直接還原法進行沉積1圈時，Cu2 O/CuO為5.05，但隨圈數增加比率降至3.95。而以先還原後氧化法進行沉積時，隨圈數增加Cu2 O/CuO微幅上升，這表示先還原後氧化法可使Cu2 O奈米粒子穩定地生成。Referring to Table 2, it can be found that Cu 2 O/CuO is 5.05 when deposited by direct reduction, but the ratio decreases to 3.95 as the number of turns increases. When deposited by the first reduction and oxidation method, the Cu 2 O/CuO increases slightly with the number of turns, which means that the Cu 2 O nanoparticle can be stably formed by the first reduction and oxidation method.
再者，同樣參照表2，由針對Cu2 O各晶格面變化的比較可發現，隨沉積圈數的增加，進行直接還原法會使Cu2 O(111)下降而Cu2 O(110)增加，這表示進行直接還原法時較容易在Cu2 O(111)上沉積；相對地，以先還原後氧化法進行沉積時，則使Cu2 O(110)下降而Cu2 O(200)顯著增加，這表示進行先還原後氧化法能產生具有立方結構的銅奈米粒子。Furthermore, referring also to Table 2, it can be found from the comparison of the lattice plane changes for Cu 2 O that as the number of deposition turns increases, the direct reduction method causes Cu 2 O(111) to decrease and Cu 2 O(110). Increasing, this means that it is easier to deposit on Cu 2 O(111) when performing the direct reduction method; relatively, when it is deposited by the first reduction and oxidation method, Cu 2 O(110) is decreased and Cu 2 O(200) Significantly increased, this means that the oxidation process can produce copper nanoparticles with a cubic structure after the first reduction.
(三)銅奈米粒子的電化學特性及應用(III) Electrochemical Characteristics and Application of Copper Nanoparticles
A.胺基酸電化學特性A. Electrochemical properties of amino acids
以循環伏安法並使用直接還原法及先還原後氧化法在不同掃瞄圈數下所形成的銅奈米粒子對胺基酸進行檢測。The amino acid was detected by cyclic voltammetry and using copper nanoparticles formed by direct reduction method and first reduction oxidation method under different scanning cycles.
所使用的檢測標的、儀器、工作電極及檢測參數如下：The test targets, instruments, working electrodes and test parameters used are as follows:
檢測樣本：1 mM α-丙胺酸、1 mM β-丙胺酸和1 mM γ-胺基丁酸Test sample: 1 mM α-alanine, 1 mM β-alanine and 1 mM γ-aminobutyric acid
儀器：恆電位儀(CHI7105,CH Instrument)Instrument: Potentiostat (CHI7105, CH Instrument)
工作電極：以不同沉積步驟所得之沉積有銅奈米粒子的網版印刷碳電極Working electrode: screen printing carbon electrode deposited with copper nanoparticles obtained in different deposition steps
檢測參數：在10 mM之磷酸鹽緩衝溶液(pH值為8) 中，從電位-0.3 V到+0.3 V以50 mV/s的掃瞄速率進行檢測。Test parameters: in 10 mM phosphate buffer solution (pH 8) The detection is performed at a scan rate of 50 mV/s from a potential of -0.3 V to +0.3 V.
圖7a到圖7d為進行不同沉積步驟所得之沉積有銅奈米粒子的網版印刷碳電極對α-丙胺酸、β-丙胺酸和γ-胺基丁酸進行檢測的循環伏安圖。請參照圖7a到圖7d，任一α-丙胺酸的氧化波電位(約在+0.18 V)皆大於背景值(磷酸鹽緩衝溶液的氧化波電位)，此表示任何一個網版印刷碳電極皆可氧化α-丙胺酸；然而，僅有以先還原後氧化法進行沉積所得的網版印刷碳電極可氧化β-丙胺酸和γ-胺基丁酸，且隨沉積圈數的增加，對β-丙胺酸和γ-胺基丁酸的氧化效應增加。Figures 7a through 7d are cyclic voltammograms for the detection of alpha-alanine, beta-alanine and gamma-aminobutyric acid by screen printing carbon electrodes deposited with copper nanoparticles obtained in different deposition steps. Referring to Figures 7a to 7d, the oxidation potential of any α-alanine (about +0.18 V) is greater than the background value (oxidation wave potential of the phosphate buffer solution), which means that any screen printing carbon electrode is Oxidation of α-alanine; however, only the screen printing carbon electrode obtained by deposition after the first reduction and oxidation method can oxidize β-alanine and γ-aminobutyric acid, and as the number of deposition cycles increases, β - The oxidative effect of alanine and gamma-aminobutyric acid is increased.
接著，根據圖7a到圖7d中的氧化波峰電流數據，以式1來計算各網版印刷碳電極對α-丙胺酸、β-丙胺酸和γ-胺基丁酸的電流響應比率(△R)，如下表3所示。Next, according to the oxidation peak current data in FIGS. 7a to 7d, the current response ratio of each screen printing carbon electrode to α-alanine, β-alanine and γ-aminobutyric acid is calculated by Formula 1 (ΔR). ), as shown in Table 3 below.
△R=△I/Ipa-PBS (%) 式1△R=△I/I pa-PBS (%) Equation 1
其中，△I=Ipa-AA -Ipa-PBS ，Ipa-AA 與Ipa-PBS 分別為磷酸鹽緩衝溶液中含有胺基酸與不含胺基酸之所得的氧化波峰電流。Among them, ΔI=I pa-AA -I pa-PBS , I pa-AA and I pa-PBS are oxidation peak currents obtained by containing an amino acid and no amino acid in a phosphate buffer solution, respectively.
請參照表3，結果顯示無論以何種沉積方式所得的電 極都可對α-丙胺酸進行顯著的氧化反應。然而，隨著圈數的增加，以直接還原法製得的電極對α-丙胺酸的電流響應比率下降，但以先還原後氧化法製得的電極對α-丙胺酸的電流響應比率卻增加。另外，由先還原後氧化法製得的電極對α-丙胺酸的電流響應比率皆大於由直接還原法製得的電極。Please refer to Table 3, the results show that regardless of the deposition method Extremely significant oxidation of alpha-alanine is possible. However, as the number of turns increases, the current response ratio of the electrode prepared by the direct reduction method to α-alanine decreases, but the current response ratio of the electrode prepared by the first reduction-oxidation method to α-alanine increases. In addition, the current response ratio of the electrode prepared by the first reduction and oxidation method to α-alanine is larger than that of the electrode obtained by the direct reduction method.
值得注意的是，僅有由先還原後氧化法所得到之沉積有立方結構銅奈米粒子的網版印刷碳電極對β-丙胺酸和γ-胺基丁酸具有電化學反應，並且隨著圈數增加，對β-丙胺酸的電流響應比率顯著增加。It is worth noting that only the screen printing carbon electrode deposited with the cubic copper nanoparticles obtained by the first reduction oxidation method has an electrochemical reaction with β-alanine and γ-aminobutyric acid, and As the number of turns increases, the current response ratio to β-alanine increases significantly.
此外，比對先還原後氧化法所沉積之銅奈米粒子的粒徑分佈(如圖5e所示)，發現300 nm至400 nm的立方結構銅奈米粒子皆可用於檢測α-胺基酸、β-胺基酸和γ-胺基酸。In addition, by comparing the particle size distribution of the copper nanoparticles deposited by the first reduction and oxidation method (as shown in Fig. 5e), it is found that cubic nanometer copper nanoparticles of 300 nm to 400 nm can be used for the detection of α-amino acid. , β-amino acid and γ-amino acid.
B.胺基酸分析應用B. Amino acid analysis application
以流動式注入分析(Flow injection analysis，FIA)法使用先還原後氧化法進行6圈所生成之銅奈米粒子對胺基酸進行檢測。The amino acid produced by the flow reduction analysis (FIA) method using the copper nanoparticle generated by the first reduction and oxidation method was detected.
所使用的儀器、工作電極及檢測參數如下：The instrument, working electrode and test parameters used are as follows:
儀器：蠕動幫浦Instrument: Creeping pump
手動注入閥，具100 μl連接回路的鐵氟龍管(型號7125,Rehodyne,CA)Manual injection valve, Teflon tube with 100 μl connection loop (Model 7125, Rehodyne, CA)
薄層偵測電化學系統(Zensor SF-100)(特別為網版印刷電極所設計)Thin layer detection electrochemical system (Zensor SF-100) (especially designed for screen printing electrodes)
工作電極：使用先還原後氧化法進行6圈所得之沉積有立方結構銅奈米粒子的網版印刷碳電極Working electrode: Screen printing carbon electrode deposited with cubic copper nanoparticles by using the first reduction and oxidation method
檢測參數：於10 mM的磷酸鹽緩衝溶液中，以固定的電位+0.18 V並流速50 rpm下對不同濃度之α-丙胺酸、β-丙胺酸和γ-胺基丁酸進行檢測。Detection parameters: Different concentrations of α-alanine, β-alanine and γ-aminobutyric acid were detected in a 10 mM phosphate buffer solution at a fixed potential of +0.18 V and a flow rate of 50 rpm.
圖8a到圖8c顯示使用先還原後氧化法進行6圈所得之沉積有銅奈米粒子的網版印刷碳電極對不同濃度之α-丙胺酸、β-丙胺酸和γ-胺基丁酸的電化學變化圖。圖9a到圖9c為不同濃度之α-丙胺酸、β-丙胺酸和γ-胺基丁酸的校正曲線。Figure 8a to Figure 8c show the screen printing carbon electrode deposited with copper nanoparticles using 6 cycles of the first reduction and oxidation method for different concentrations of α-alanine, β-alanine and γ-aminobutyric acid. Electrochemical change diagram. Figures 9a to 9c are calibration curves for various concentrations of alpha-alanine, beta-alanine and gamma-aminobutyric acid.
由圖8a及圖9a可知，所述工作電極對α-丙胺酸檢測的線性範圍為5 μM到1 mM(R2 為0.998)，而檢測極限為5 μM。而由圖7b及圖8b可知，所述工作電極對β-丙胺酸檢測的線性範圍為10 μM到1 Mm(R2 為0.990)，而檢測極限為10 μM。另外，由圖8c及圖9c可知，所述工作電極對γ-胺基丁酸於高濃度時的檢測，線性範圍為100 μM到1 mM(R2 為0.975)，而對於低濃度的檢測其線性範圍為25 μM到100 μM(R2 為0.993)，且檢測極限為25 μM。As can be seen from Figures 8a and 9a, the linear range of detection of the working electrode for α-alanine is 5 μM to 1 mM (R 2 is 0.998), and the detection limit is 5 μM. 7b and 8b, the linear range of the working electrode for β-alanine detection is 10 μM to 1 Mm (R 2 is 0.990), and the detection limit is 10 μM. In addition, as can be seen from FIG. 8c and FIG. 9c, the detection of the γ-aminobutyric acid at a high concentration of the working electrode has a linear range of 100 μM to 1 mM (R 2 is 0.975), and for the detection of low concentration The linear range is 25 μM to 100 μM (R 2 is 0.993) with a detection limit of 25 μM.
基於上述，本發明之沉積在工作電極上之具有立方結構且邊長尺寸包括300 nm至400 nm的銅奈米粒子能以免標定方式於電化學安培法直接檢測α-胺基酸、β-胺基酸或γ-胺基酸。Based on the above, the copper nanoparticles deposited on the working electrode and having a cubic structure and having a side length including 300 nm to 400 nm can directly detect α-amino acid and β-amine by electrochemical amperometric method in a calibration-free manner. A base acid or a γ-amino acid.
綜上所述，上述實施例所提出之銅奈米粒子的製造方 法無須使用保護劑，並利用先沉積後氧化的方式直接在電極上沉積具有立方結構的銅奈米粒子。此外，上述實施例所提出之銅奈米粒子的製造方法可僅以電位來控制奈米粒子的表面狀態，而產生不同粒徑尺寸的立方結構奈米粒子。上述實施例所提出之銅奈米粒子具有立方結構且其邊長尺寸包括250 nm至450 nm。另外，本發明所提出之胺基酸的檢測方法以上述銅奈米粒子進行檢測，且能直接以電化學安培法同時對α-胺基酸、β-胺基酸或γ-胺基酸進行免標定式的電催化反應。In summary, the manufacturer of the copper nanoparticles proposed in the above embodiments The method does not require the use of a protective agent, and deposits copper nanoparticles having a cubic structure directly on the electrode by means of first deposition and oxidation. Further, the method for producing copper nanoparticles proposed in the above embodiments can control the surface state of the nanoparticles by electric potential only, and produce cubic nanoparticles having different particle size sizes. The copper nanoparticles proposed in the above embodiments have a cubic structure and have a side length dimension of 250 nm to 450 nm. In addition, the method for detecting an amino acid proposed by the present invention is detected by the above copper nanoparticles, and the α-amino acid, the β-amino acid or the γ-amino acid can be simultaneously directly subjected to electrochemical amperometry. Calibration-free electrocatalytic reaction.
雖然本發明已以實施例揭露如上，然其並非用以限定本發明，任何所屬技術領域中具有通常知識者，在不脫離本發明之精神和範圍內，當可作些許之更動與潤飾，故本發明之保護範圍當視後附之申請專利範圍所界定者為準。Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.
S100~S102‧‧‧步驟S100~S102‧‧‧Steps
S200~S202‧‧‧步驟S200~S202‧‧‧Steps
圖1繪示本發明之第一實施例之銅奈米粒子的製造方法的流程圖。1 is a flow chart showing a method of manufacturing copper nanoparticles according to a first embodiment of the present invention.
圖2繪示本發明之第二實施例之胺基酸的檢測方法的流程圖。2 is a flow chart showing a method for detecting an amino acid according to a second embodiment of the present invention.
圖3以直接還原法沉積銅奈米粒子之第1圈到第6圈的循環伏安圖。Figure 3 is a cyclic voltammogram of the first to sixth turns of the copper nanoparticles deposited by direct reduction.
圖4a為以先還原後氧化法沉積銅奈米粒子之第1圈到第6圈的循環伏安圖。Figure 4a is a cyclic voltammogram of the first to sixth turns of the copper nanoparticles deposited by the first reduction and subsequent oxidation.
圖4b為對應圖3a中之第1圈到第5圈後進行氧化步 驟的循環伏安圖。Figure 4b shows the oxidation step after the first to fifth laps in Figure 3a. Cyclic voltammogram.
圖5a到圖5d為進行不同沉積步驟時之銅奈米粒子的掃描式電子顯微鏡圖，其中比例尺為1 μm。Figures 5a to 5d are scanning electron micrographs of copper nanoparticles in different deposition steps, with a scale of 1 μm.
圖5e為具有立方結構之銅奈米粒子的粒徑分佈圖。Fig. 5e is a particle size distribution diagram of copper nanoparticles having a cubic structure.
圖6為進行不同沉積步驟所得的沉積有銅奈米粒子之網版印刷碳電極的XRD 2θ頻譜圖。Fig. 6 is a XRD 2θ spectrum diagram of a screen printing carbon electrode deposited with copper nanoparticles obtained by performing different deposition steps.
圖7a到圖7d為進行不同沉積步驟所得之沉積有銅奈米粒子的網版印刷碳電極對α-丙胺酸、β-丙胺酸和γ-胺基丁酸進行檢測的循環伏安圖。Figures 7a through 7d are cyclic voltammograms for the detection of alpha-alanine, beta-alanine and gamma-aminobutyric acid by screen printing carbon electrodes deposited with copper nanoparticles obtained in different deposition steps.
圖8a到圖8c顯示使用先還原後氧化法進行6圈所得之沉積有銅奈米粒子的網版印刷碳電極對不同濃度之α-丙胺酸、β-丙胺酸和γ-胺基丁酸的電化學變化圖。Figure 8a to Figure 8c show the screen printing carbon electrode deposited with copper nanoparticles using 6 cycles of the first reduction and oxidation method for different concentrations of α-alanine, β-alanine and γ-aminobutyric acid. Electrochemical change diagram.
圖9a到圖9c為不同濃度之α-丙胺酸、β-丙胺酸和γ-胺基丁酸的校正曲線。Figures 9a to 9c are calibration curves for various concentrations of alpha-alanine, beta-alanine and gamma-aminobutyric acid.
S100、S102‧‧‧步驟S100, S102‧‧‧ steps
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| JP2008057041A (en) * | 2006-08-29 | 2008-03-13 | Samsung Electro Mech Co Ltd | Method for producing copper nanoparticle in cubic form |
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