CN102721723B - Hogwash oil identifying method based on volatile matter - Google Patents

Abstract

The invention discloses a hogwash oil identifying method based on volatile matter. The method comprises the following steps of (1) designing a molecular wire array probe; (2) constructing a molecular wire piezoelectric sensor device; (3) analyzing a known sample; (4) extracting feature identifying information; and (5) identifying a sample to be tested: achieving fast identification of hogwash oil by comparing an output feature value with a feature value of the known sample. The hogwash oil identifying method based on the volatile matter has the advantages of being high in sensitivity, fast in detection, convenient to operate, low in cost and the like, and can provide a reliable basis for the law-enforcing department and inspection bodies to perform sampling inspection on quality of oil products.

Description

A kind of hogwash fat discrimination method based on volatility thing group

Technical field

The present invention relates to the discrimination method of hogwash fat, particularly a kind of hogwash fat discrimination method based on volatility thing group.

Background technology

Hogwash fat (waste oil of narrow sense) is that catering industry washes dishes, washes the dishes, residue leftovers etc. flows into trench, in oil interceptor, fish for, and through the grease of pulp water separation, thermal dehydration, decolorization refining processing.Due to similar to the oil with common edible in appearance impalpable of hogwash fat, some lawless persons are ordered about by juice in recent years, extract in a large number hogwash fat and sell at a low price to market.Owing to being mixed with sewage, rubbish, washing agent in swill and turning sour and lose food, in hogwash fat after processing is refined, contain the carcinogens such as a large amount of bacteriotoxins, lipid peroxide, benzopyrene, alkanes and aflatoxins, and heavy metal ion, the hydroxyl valency of grease is considerably beyond the edible oil hygienic standard of national regulation.By hogwash fat is carried out to toxicological study, result shows, the long-term hogwash fat of taking in will cause human development's obstacle, easily suffer from enteritis, and have the pathologies such as liver, the heart and kidney enlargement and fatty liver, in addition, aflatoxin in hogwash fat, its toxicity is 68 times of arsenic, easily causes the canceration of many internal organs of human body, as position cancerations such as liver cancer, sdenocarcinoma of stomach, kidney, the carcinoma of the rectum, breast cancer and ovary, small intestines.

About the existing method of discrimination of hogwash fat, can be divided at present three major types: organoleptic detection, conventional sense and instrument detect.Organoleptic detection differentiates by seeing, hear, taste, listen, ask five aspects, and this detection method exists very large subjectivity, and strong evidence data cannot be provided; Conventional detection and identification method is mainly that the total Physical and chemical characteristics of Various Edible is compared, as acid value, iodine number, peroxide value, degree of unsaturation, density, specific heat, moisture, solidifying point, index of refraction and unsaponifiable matter content etc., thereby the character of grease is evaluated; Because conventional method need be done a large amount of early-stage preparations, process is loaded down with trivial details, therefore some fast detection methods on conventional method basis, have been developed, as adopt acid value and the peroxide value of quick measuring card method fast detecting oil, whether thereby it is adulterated to differentiate edible oil, this method is made card form using the scraps of paper as carrier, react with free fatty acid or superoxide by developer, its degree developing the color on the scraps of paper is directly proportional to the content of free fatty acid or superoxide, reaches the sxemiquantitative of acid value or peroxide value with this.Due to the similarity of physicochemical characteristic between grease, these methods are always ineffective.Along with scientific and technological development, the appearance of exact instrument, and computing machine is in the infiltration in analytical chemistry field, has occurred utilizing advanced analysis instrument and has utilized the method for stoichiometric chemistry to solve the adulterated difficult problem of edible oil, and having obtained comparatively satisfied result.Roughly as follows: gas chromatography determination cholesterol level detects the method for hogwash fat; Micro-wave digestion-inductivity coupled plasma mass spectrometry (ICP-MS) is measured trace element in oil simultaneously, result shows that element of Fe, Cr, Zn, Mn content in hogwash fat obviously exceeds edible oil, and Hg, Sn, Co, Sb, Tl, Mo are no matter at edible oil or content is all lower than detectability in hogwash fat; Thin-layer chromatographic analysis finds that the thin-layer chromatography of hogwash fat has obvious hangover spot, qualified edible oil does not have, hangover spot composition separates and carries out infrared analysis through column chromatography, and result shows, the hangover composition of hogwash fat is aldehyde, the ketone compounds that qualified edible oil does not contain; Whether adopt the content of fatty acid in gas chromatography determination edible oil and fat, differentiate in edible oil adulteratedly, research, the massfraction distribution of the relative degree of unsaturation of fatty acid (U/R) value and fatty acid can be differentiated waste oil if showing.But it is huge, expensive that instrument detects equipment needed thereby, and complex operation, is not suitable for promoting the use of.

Therefore, research easy and simple to handle, hogwash fat discrimination method fast and accurately is imperative.

Summary of the invention

The object of the invention is to overcome existing method weak point and a kind of hogwash fat discrimination method of easy, quick, accurate, low cost is provided.

In order to realize above-mentioned technical purpose, technical scheme of the present invention is that a kind of hogwash fat discrimination method based on volatility thing group, comprises the following steps:

Step 1: taking comb electrode as conductance electrode, sensitive membrane taking conducting high polymers thing or electrical-conductive nanometer high molecular polymer molecular wire as the special volatility thing of hogwash fat group, modify to comb electrode final vacuum dryly by being coated with method or infusion process, prepare molecular wire array probe;

Step 2: the part taking the prepared molecular wire array probe of step 1 as sensor, setting comprises sensor, frame of reference, the hardware system of display system, wherein sensor comprises molecular wire array probe, for filling the test bottle that detects oil sample, temperature regulating device, oscillatory circuit and piezoelectric quartz crystal sensor, described molecular wire array probe is inserted in test bottle, described test bottle is arranged at temperature regulating device, the output terminal of molecular wire array probe is connected to respectively oscillatory circuit and piezoelectric quartz crystal sensor, the output terminal of piezoelectric quartz crystal sensor is connected to oscillatory circuit, described frame of reference comprises a point frequency meter, driving circuit and single-chip microcomputer, the input end of described point frequency meter is connected to the output terminal of oscillatory circuit, divide the output terminal of frequency meter to be connected to respectively driving circuit and single-chip microcomputer, the output terminal of driving circuit connects single-chip microcomputer, the input end of single-chip microcomputer is also connected to oscillatory circuit, described display system comprises display, described display is connected to single-chip microcomputer by MAX232 interface,

Step 3: oil sample is added in test bottle, insert molecular wire array probe, oil sample liquid level and probe keep 4cm, test bottle is inserted in the temperature regulating device of molecular wire piezoelectric sensing device, regulate temperature regulating device, set temperature is 70 ° of C, starts to detect after equalized temperature;

Step 4: will process by the frequency data of the measured each array of molecular wire array probe, obtain frequency-shift data, frequency-shift data is analyzed, characteristic information extraction, obtains the eigenwert that can differentiate hogwash fat.

Described a kind of hogwash fat discrimination method based on volatility thing group, the sensitive membrane material described in step 1 is polyaniline, polypyrrole or wherein at least one of polythiophene.

Described a kind of hogwash fat discrimination method based on volatility thing group, the conducting high polymers thing described in step 1 or electrical-conductive nanometer high molecular polymer are to adopt chemical oxidative polymerization or interface synthetic method or electrochemical synthesis to be prepared from.

Described a kind of hogwash fat discrimination method based on volatility thing group, the molecular wire array probe described in step 1 is that 6 comb electrodes adopt 2 × 3 array combination to form.

Described a kind of hogwash fat discrimination method based on volatility thing group, in described molecular wire array probe, each comb electrode connects independently oscillatory circuit with wire respectively.

Described a kind of hogwash fat discrimination method based on volatility thing group, is characterized in that, frequency shift value Δ F for the output data acquisition of each molecular wire array in step 4 _i, frequency shift value Δ F _iobtain by method of difference, formula is:

ΔF _i=F _i-F ₀，

Wherein F _ifor real-time frequency, F ₀for piezoelectric quartz crystal original frequency.Adopt frequency shift value Δ F _iobject be the impact of avoiding because piezoelectric quartz crystal original frequency value difference causes in different oscillatory circuits.

Described a kind of hogwash fat discrimination method based on volatility thing group, is characterized in that, extracts eigenwert X in step 4 _icomputing formula be:

X _i=|f ₁'(t)| ^max+|f ₂'(t)| ^max+|f ₃'(t)| ^max+……|f _a'(t)| ^max

Wherein, | f _a' (t) | ^maxfor a molecular wire array probe in i sample frequency displacement-time response curve the maximal value of absolute value of first derivation value, wherein a is more than or equal to 1 and be less than or equal to 6 integer.

The innovation that the present invention contrasts prior art is, thereby has proposed the new method with special volatility thing group is carried out hogwash fat discriminating in molecular wire piezoelectric sensing device analysis hogwash fat; Build the molecular wire piezo-electric device that molecular wire array probe and piezoelectric quartz crystal sensor merge.

Technique effect of the present invention is,

1, be easy to regulate and control output signal strength by the preparation condition of Molecular regulator wire film and the electrode parameter of change comb electrode;

2, the impact of electric double layer capacitance has been avoided in the use of piezoelectric quartz crystal sensor, has improved the stability of electric signal, has strengthened signal to noise ratio (S/N ratio);

3, molecular wire array probe and piezoelectric quartz crystal sensor have significantly improved the degree of accuracy detecting after merging.

4, the robotization processing that in device, the combination of frame of reference, display system can implement device.

Brief description of the drawings

Fig. 1 is the structural representation of apparatus of the present invention;

Wherein: A-sensor, B-frame of reference, C-display system;

1-molecular wire array probe; 2-test bottle; 3-temperature regulating device; 4-oscillatory circuit; 5-piezoelectric quartz crystal sensor; 6-divides frequency meter; 7-driving circuit; 8-single-chip microcomputer; 9-display;

Fig. 2 is the schematic diagram that molecular wire array probe is overlooked (a) and side-looking (b);

10-comb electrode; 11-molecular wire; 12-connector; 13-wire

Fig. 3 is the frequency displacement response curve of different molecular wire array probe.

Fig. 4 is the first derivation curve of frequency displacement response curve.

Embodiment

Below in conjunction with drawings and Examples, the invention will be further described.

The principle of foundation of the present invention is: research shows, in oil product, contain abundant volatile ingredient, if oil quality changes, can there is significant variation in its volatile ingredient, as produce one in acetic acid, propionic acid, butyric acid, valeric acid, caproic acid etc., two or more; Molecular wire film electrical quantity in the time of adsorb volatile thing group can change, and piezoelectric quartz crystal sensor changes the electrical quantity of the object of serial connection with it and has a sensitive frequency change, referring to formula (1):

$\mathrm{\ΔF}=\frac{\mathrm{\π}{F_0}^2{C}_q(4{\mathrm{\π}}^2{F_0}^2{C_s}^{2}Y+4\mathrm{\π}{F}_0{C}_{s}G-Y{G}^2)}{{[4{\mathrm{\π}}^2{F_0}^2{C}_s(C_0+C_s)-2\mathrm{\π}{F}_0{C}_0\mathrm{YG}+G^2]}^2}\·\mathrm{\ΔG}---\left(1\right)$

Δ F=F in formula _i-F ₀, F _irepresent resonance frequency, represent the fundamental frequency of quartz crystal;

C _qand C ₀represent respectively dynamic capacity and the direct capacitance of quartz crystal sensor;

G and C _sthe electricity that is respectively surveyed object is led and electric capacity: G=κ χ, and κ is the electrode constant of the electrode that is connected in series with piezoelectric quartz crystal sensor, χ is the conductivity of surveyed object; C _s=κ ε+C _p, ε is the specific inductive capacity of surveyed object, C _pfor and two wires that are connected of electrode between stray capacitance;

Basic thought of the present invention: build molecular wire piezoelectric sensing device by fusion molecule wire array probe and piezoelectric quartz crystal sensor, realize the analysis of the special volatility thing group to hogwash fat, thereby propose the new method that hogwash fat is differentiated.

According to above principle and thought, the technical scheme of setting up is as follows,

Adopt the molecular wire piezoelectric sensing device shown in Fig. 1 to realize the discriminating of hogwash fat.Setting comprises sensor, frame of reference, the hardware system of display system, wherein sensor comprises molecular wire array probe, for filling the test bottle that detects oil sample, temperature regulating device, oscillatory circuit and piezoelectric quartz crystal sensor, molecular wire array probe is inserted in test bottle, test bottle is arranged at temperature regulating device, the output terminal of molecular wire array probe is connected to respectively oscillatory circuit and piezoelectric quartz crystal sensor by connector with wire, the output terminal of piezoelectric quartz crystal sensor is connected to oscillatory circuit, frame of reference comprises a point frequency meter, driving circuit and single-chip microcomputer, divide the input end of frequency meter to be connected to the output terminal of oscillatory circuit, divide the output terminal of frequency meter to be connected to respectively driving circuit and single-chip microcomputer, the output terminal of driving circuit connects single-chip microcomputer, the input end of single-chip microcomputer is also connected to oscillatory circuit, display system comprises display, display is connected to single-chip microcomputer.

The substrate comb electrode that wherein molecular wire array probe adopts be adopt terahertz wave quasi-optics by sawing sheet, heavy copper, figure transfer, graphic plating, move back film, etching, moulding, testing process the many groups of unit comb electrodes that are arranged in parallel be deposited into the substrate of pi film; Conducting high polymers thing or electrical-conductive nanometer high molecular polymer are to adopt chemical oxidative polymerization or interface synthetic method or electrochemical synthesis to be prepared from.Chemical oxidative polymerization, interface synthetic method and electrochemical synthesis can be specifically with reference to H.R. A Er Cook, and F.W. orchid is general, J.E. mark, contemporary polymer chemistry [M], Beijing: Chemical Industry Press, 2006; D.D.Sawall, R.M.Villahermosa, R.A.Lipeles, and Alan R.Hopkins, Interfacial Polymerization of Polyaniline Nanofibers Grafted to Au Surfaces, Chem.Mater2004,16,1606-1608; The preparation of molecular wire probe comprises three kinds of methods: 1) by conducting high polymers thing or electrical-conductive nanometer high molecular polymer molecular wire are dissolved in to organic solvent as in dimethyl sulfoxide (DMSO), make conducting high polymers thing solution, get 1 this solution of μ L with micropipettor and drip to comb electrode surface by the evenly coating or comb electrode is immersed to 10 ~ 30min in this solution of spin coating instrument, then vacuum drying and obtaining; 2) directly conducting high polymers thing is deposited on the comb electrode of working electrode by electrochemical synthesis or interfacial polymerization.

Piezoelectric quartz crystal sensor is 9MHz AT-cut type, and two sides is silver-plated, purchases to Beijing 707 factories, and molecular wire array probe is connected by wire with piezoelectric quartz crystal sensor.

In test process, molecular wire array probe is combined with the special volatility thing group of surveyed oil samples, causes the frequency change of piezoelectric quartz crystal sensor, obtains response signal.And the collection of signal is by computer control, first sent instructions to single-chip microcomputer by MAX232 interface by computing machine, need to gather the signal of which array, computer control hyperchannel selector switch, open corresponding collection signal passage, the signal input point frequency meter gathering, a point frequency meter is passed to single-chip microcomputer, and single-chip microcomputer is passed to display system by data-interface.All frequency data are by single-chip microcomputer processing, analysis, extraction eigenwert, and with data with existing storehouse in the eigenwert of normal oil sample compare, and export identification result.

The flow process of differentiating hogwash fat by molecular wire piezoelectric sensing device is (taking swill oil sample 5 as example): oil sample to be measured is added in test bottle, insert molecular wire array probe, oil sample liquid level and probe maintain a certain distance, test bottle is inserted to the detecting position of molecular wire piezoelectric sensing device, regulate temperature regulating device, set temperature is 70 ° of C, balance 20min, starting molecular wire piezoelectric sensing device operation interface detects, obtain the each array of molecular wire (totally 6) frequency data, by software, frequency data are exported to (in table 1) with frequency displacement, obtain real-time frequency displacement response curve (see figure 3) simultaneously.

Frequency shift value (the Δ F of table 1 different molecular wire probe different time in swill oil sample 5 _i=F _i-F ₀)

Taking the time in table 1 as horizontal ordinate, frequency shift value is ordinate, can obtain curve frequency displacement-time response of 6 molecular wire probes, sees Fig. 3, and after each curve first derivation, the maximal value of getting its absolute value is extraction value (referring to Fig. 4), the results are shown in Table 2:

The extraction value of table 2 different molecular wire array

Extraction value to each molecular wire probe is carried out data fusion, the extraction value sum of 6 sensor output signals in array is represented to the eigenwert of swill oil sample 5, eigenwert (the X of swill oil sample 5 ₅) be the extraction value sum of 6 molecular wire arrays in table 2:

X ₅=0.058+0.667+1.808+3.792+3.642+2.508=12.475 (2)

From formula (2), the eigenwert of swill oil sample 5 is 12.475

Use the same method and analyzed 30 of oil samples (each 15 of qualified oil sample and swill oil sample), its eigenwert is in table 3, as seen from table, the mean eigenvalue of normal oil sample is 5.366 ± 1.582, and the mean eigenvalue of swill oil sample is 12.231 ± 1.351, two stack features values are carried out to T inspection, obtain | T ₀|=12.7808>2.7633(T _0.005(28)) result shows two class values there were significant differences in 99% fiducial interval.According to sample results, in this method eigenwert X _i>=9 sample is judged to hogwash fat.

The eigenwert of table 3 oil sample

Claims (7)

1. the hogwash fat discrimination method based on volatility thing group, is characterized in that, comprises the following steps:

Step 1: taking comb electrode as conductance electrode, sensitive membrane taking conducting high polymers thing or electrical-conductive nanometer high molecular polymer molecular wire as the special volatility thing of hogwash fat group is modified to comb electrode final vacuum dryly by being coated with method or infusion process, prepares molecular wire array probe;

Step 2: the part taking the prepared molecular wire array probe of step 1 as sensor, setting comprises sensor, frame of reference, the hardware system of display system, wherein sensor comprises molecular wire array probe, for filling the test bottle that detects oil sample, temperature regulating device, oscillatory circuit and piezoelectric quartz crystal sensor, described molecular wire array probe is inserted in test bottle, described test bottle is arranged at temperature regulating device, the output terminal of molecular wire array probe is connected to respectively oscillatory circuit and piezoelectric quartz crystal sensor, the output terminal of piezoelectric quartz crystal sensor is connected to oscillatory circuit, described frame of reference comprises a point frequency meter, driving circuit and single-chip microcomputer, the input end of described point frequency meter is connected to the output terminal of oscillatory circuit, divide the output terminal of frequency meter to be connected to respectively driving circuit and single-chip microcomputer, the output terminal of driving circuit connects single-chip microcomputer, the input end of single-chip microcomputer is also connected to oscillatory circuit, described display system comprises display, described display is connected to single-chip microcomputer by MAX232 interface,

Step 3: oil sample is added in test bottle, insert molecular wire array probe, oil sample liquid level and probe keep 4cm, test bottle is inserted in the temperature regulating device of molecular wire piezoelectric sensing device, regulate temperature regulating device, set temperature is 70 DEG C, starts to detect after equalized temperature;

Step 4: will process by the frequency data of the measured each array of molecular wire array probe, obtain frequency-shift data, frequency-shift data is analyzed, characteristic information extraction, obtains the eigenwert that can differentiate hogwash fat.

2. a kind of hogwash fat discrimination method based on volatility thing group according to claim 1, is characterized in that, the sensitive membrane material described in step 1 is polyaniline, polypyrrole or wherein at least one of polythiophene.

3. a kind of hogwash fat discrimination method based on volatility thing group according to claim 1, it is characterized in that, the conducting high polymers thing described in step 1 or electrical-conductive nanometer high molecular polymer are to adopt chemical oxidative polymerization or interface synthetic method or electrochemical synthesis to be prepared from.

4. a kind of hogwash fat discrimination method based on volatility thing group according to claim 1, is characterized in that, the molecular wire array probe described in step 1 is that 6 comb electrodes adopt 2 × 3 array combination to form.

5. a kind of hogwash fat discrimination method based on volatility thing group according to claim 4, is characterized in that, in described molecular wire array probe, each comb electrode connects independently oscillatory circuit with wire respectively.

6. a kind of hogwash fat discrimination method based on volatility thing group according to claim 1, is characterized in that, frequency shift value △ F for the output data acquisition of each molecular wire array in step 4 _i, frequency shift value △ F _iobtain by method of difference, formula is:

△F _i＝F _i-F ₀，

Wherein F _ireal-time frequency, F ₀for piezoelectric quartz crystal original frequency.

7. a kind of hogwash fat discrimination method based on volatility thing group according to claim 1, is characterized in that, extracts eigenwert X in step 4 _icomputing formula be:

X _i＝|f ₁'(t)| ^max+|f ₂'(t)| ^max+|f ₃'(t)| ^max+……|f ₆'(t)| ^max

Wherein, | f _a' (t) | ^maxfor a molecular wire array probe in i sample frequency displacement-time response curve the maximal value of absolute value of first derivation value, wherein a is more than or equal to 1 and be less than or equal to 6 integer.