CN110628039B

CN110628039B - Supramolecular polymer hydrogel based on bipod gelator and application thereof

Info

Publication number: CN110628039B
Application number: CN201910922241.4A
Authority: CN
Inventors: 张有明; 朱伟; 林奇; 曲文娟; 姚虹; 魏太保; 其他发明人请求不公开姓名
Original assignee: Northwest Normal University
Current assignee: Northwest Normal University
Priority date: 2019-09-27
Filing date: 2019-09-27
Publication date: 2021-06-08
Anticipated expiration: 2039-09-27
Also published as: CN110628039A

Abstract

The invention discloses a supramolecular polymer hydrogel based on a bipod gelator, which takes a reaction product of trimesoyl chloride and 4-aminopyridine as an object, a reaction product of trimesoyl chloride and isoniazid as a main body, and the gel is prepared in DMSO/H₂And the supermolecular polymer hydrogel is formed by the interaction of a host and a guest in an O system. The hydrogel has weak yellowish fluorescence and no aggregation-induced emission characteristics. Adding different metal ions into hydrogel with only Th⁴⁺The fluorescence of the gel can be enhanced and turned green. Hydrogels and Th⁴⁺Coordination occurs to form a metal gel having aggregation-induced emission characteristics. Adding different metal ions, only Hg, into the metal gel²⁺The fluorescence of the metal gel can be restored to the original intensity. Therefore, the supramolecular polymer hydrogel has very important significance in the field of ultrasensitive response of ions.

Description

Supramolecular polymer hydrogel based on bipod gelator and application thereof

Technical Field

The invention relates to a supramolecular polymer hydrogel, in particular to a supramolecular polymer hydrogel based on bipod gel factors; the invention also relates to continuous ultra-sensitive detection of Th by the supramolecular polymer hydrogel⁴⁺And Hg²⁺Belonging to the field of supramolecular polymers and the field of ion detection.

Background

In recent years, the development of new methods that enable ultrasensitive detection of different analytes plays a crucial role in biological sample and environmental safety, so ultrasensitive detection has attracted much attention. To date, methods have been reported which allow for ultra-sensitive detection of metal ions. However, these methods have several disadvantages, including high cost, complicated operation, and lack of repeatability. Therefore, it is urgently required to search for a new method capable of realizing ultra-sensitive detection of heavy metal ions. As is well known, thorium (particularly Th)⁴⁺) Is an important radioactive element which has wide application in many nuclear industries. However, Th⁴⁺The presence of excess in the environment is an important issue because it tends to have an effect on the health of the human body. In addition, Hg²⁺Can easily penetrate biological membrane, and can cause serious damage to brain and heart of human body. Therefore, for Th in the environment⁴⁺And Hg²⁺It is very important to realize ultra-sensitive detection.

Supramolecular polymer hydrogels are an important subset of the field of supramolecular polymers that can be assembled from gelators through a variety of non-covalent interactions. At present, because the supramolecular polymer hydrogel has a unique structure and excellent performance, the supramolecular polymer hydrogel is widely applied to the fields of chemical sensors, biological materials, pollutant removal, drug release, photocatalysis and the like. However, smart supramolecular polymer hydrogels prepared based on two tripodal gelators could be paired with Th⁴⁺And Hg²⁺Continuous ultrasensitive detection and separation has not been reported.

Disclosure of Invention

The invention aims to provide a supramolecular polymer hydrogel based on a bipod gelator;

another object of the invention is to provide the supramolecular polymer hydrogel based on the bipod gelator for continuously identifying Th⁴⁺And Hg²⁺And as fluorescent switches and as erasable intelligent luminescent materials.

Supramolecular polymer hydrogel based on bipod gelators

The invention relates to a supramolecular polymer hydrogel based on tripodal gelator, which takes a reaction product (FA) of trimesoyl chloride and 4-aminopyridine as a guest gelator, takes a reaction product (FH) of trimesoyl chloride and isoniazid as a host gelator and is subjected to reaction in DMSO/H₂And the supermolecular polymer hydrogel formed by the interaction of the host and the guest in the O system is marked as FHFA-G.

The guest gelator FA is prepared by stirring trimesoyl chloride and 4-aminopyridine in a mass ratio of 1: 3.2-1: 3.5 in DMF at room temperature for 20-24 hours. The main body gelator FH is prepared by stirring trimesoyl chloride and isoniazid in a ratio of 1: 3.2-1: 3.5 for 20-24 hours at room temperature in dichloromethane.

The structural formulas of the host-guest gelators FA and FH are respectively as follows:

the DMSO/H₂In the O system, DMSO and H₂The volume ratio of O is 1: 1.5-1: 2.5. Host gelator FH and guest gelator FA in DMSO/H₂The mass volume of the O system is 30-70 mg/ml; the molar ratio of the subject gelator FH to the guest gelator FA is 1: 1-1: 3.

FIG. 1 is a graph showing the change of fluorescence intensity of FHFA-G with temperature during gelation process (λ _ex= 370 nm). The results in FIG. 1 show that FHFA-G has a lower fluorescence intensity in the gel state than in the sol state, and that FHFA-G exhibits a weaker yellowish fluorescence in the gel stateIndicating that FHFA-G does not have aggregation-induced emission properties.

Second, the ultra-sensitive detection experiment of FHFA-G to different metal ions

1. FHFA-G pair Th⁴⁺Ultra-sensitive fluorescent response of

Preparing a series of 200 mu L supramolecular polymer hydrogel FHFA-G by using a micro-fluorescence cuvette, and adding 1 time equivalent of different metal ion aqueous solutions (Fe) into each gel³⁺，Hg²⁺，Ag⁺，Ca²⁺，Cu²⁺，Co²⁺，Ni²⁺，Cd²⁺，Pb² ⁺，Zn²⁺，Cr³⁺，Mg²⁺，Ba²⁺，Al³⁺，Eu³⁺，Tb³⁺，La³⁺And Th⁴⁺) The concentration of the ions was 0.1 mol/L.

FIG. 2 is a graph showing the fluorescence response of FHFA-G to different metal ions. FIG. 2 shows that only Th⁴⁺The fluorescence of FHFA-G can be enhanced and the fluorescence of the gel turned green. The addition of the rest metal ions has no obvious influence on the fluorescence of FHFA-G. The above results indicate that FHFA-G can selectively identify Th by fluorescence⁴⁺。

2、Th⁴⁺Fluorescence titration experiment for FHFA-G

FHFA-G was prepared in 200. mu.L portions using a microfluorescent cuvette, to which Th was gradually added⁴⁺The change in fluorescence intensity of the gel in the aqueous solution (concentration: 0.1 mol/L) was measured by a fluorescence spectrophotometer. FIG. 3 shows FHFA-G vs Th⁴⁺Fluorescence titration of (a) and minimum detection limit: (a)λ _ex= 370 nm) (b). As can be seen from FIG. 3a, the following Th⁴⁺The fluorescence of FHFA-G gradually increased and turned into green. By calculation, FHFA-G is relative to Th⁴⁺The fluorescence detection limit of (1) was 0.367nM (FIG. 3 b), indicating that FHFA-G can be detected against Th⁴⁺And ultra-sensitive detection is realized.

As values, FHFA-G and Th⁴⁺After interaction, a metal gel FHFA-GTh can be formed, and FHFA-GTh has green fluorescence. FIG. 4 shows FHFA-G and Th⁴⁺After the action, the metal gel FHFA-GTh is formedFluorescence spectrum converted from glue to melt glue. The results in FIG. 4 show that FHFA-GTh has stronger fluorescence intensity in the gel state than in the sol state, and FHFA-G has stronger green fluorescence in the gel state, indicating that FHFA-GTh has aggregation-induced emission characteristics.

3. FHFA-GTh for Hg²⁺Ultra-sensitive fluorescent response of

A series of FHFA-GTh solutions were prepared in a volume of 200. mu.L using a microfluorescent cuvette, and 1 equivalent of each of the aqueous solutions of different metal ions (Fe) was added to each gel³⁺，Hg²⁺，Ag⁺，Ca²⁺，Cu²⁺，Co²⁺，Ni²⁺，Cd²⁺，Pb²⁺，Zn²⁺，Cr³ ⁺，Mg²⁺，Ba²⁺，Al³⁺，Eu³⁺，Tb³⁺And La³⁺) The concentration of the ions was 0.1 mol/L. FIG. 5 is a graph of the fluorescence response of FHFA-GTh to different metal ions. As can be seen from FIG. 5, only Hg is present²⁺The fluorescence of FHFA-GTh can be weakened again and restored to the original fluorescence intensity, and the addition of the rest metal ions has no obvious influence on the fluorescence of FHFA-GTh. The above results show that FHFA-GTh can selectively identify Hg²⁺。

4、Hg²⁺Fluorotitration experiment for FHFA-GTh

A200. mu.L aliquot of FHFA-GTh was prepared in a microfluorescent cuvette, to which Hg was gradually added²⁺The change in fluorescence intensity of the gel was measured in an aqueous solution (concentration: 0.1 mol/L) by a fluorescence spectrophotometer. FIG. 6 shows FHFA-GTh vs Hg²⁺Fluorescence titration of (a) and minimum detection limit: (a)λ _ex= 370 nm) (b). As can be seen from FIG. 6a, the Hg content follows the Hg content²⁺With gradual addition, the fluorescence of FHFA-GTh gradually decreased and became again a weaker pale yellow color. The calculation shows that FHFA-GTh is corresponding to Hg²⁺The fluorescence detection limit of (2) was 0.185nM (FIG. 6 b), indicating that FHFA-GTh can detect Hg²⁺And ultra-sensitive detection is realized.

Third, based on FHFA-G to Th⁴⁺And Hg²⁺Preparing corresponding fluorescent switch by continuous fluorescent response

A200. mu.L aliquot of FHFA-G was prepared using a microfluorescent cuvette. Adding a certain amount of Th into FHFA-G⁴⁺The fluorescence of the gel was significantly enhanced, and then Hg was added²⁺The fluorescence intensity of the gel was significantly reduced. By repeating the above steps, the fluorescence of FHFA-G can form an "off-on-off" cycle, and this cycle can be repeated multiple times (FIG. 7). Therefore, the characteristics of FHFA-G can be used for preparing a metal ion response fluorescent switch.

Four, FHFA-G pair Th⁴⁺And Hg²⁺Analysis of the test mechanism

We identified the presence of these peaks by HRMS, FT-IR, XRD,¹H-NMR, SEM and TEM analyzed FHFA-G vs Th⁴⁺And Hg²⁺The mechanism of (4). FHFA-G and Th known from HRMS⁴⁺The formed complex ratio is 1:1, and FHFA-GTh and Hg²⁺A 1:3 complexing ratio is formed between. From FT-IR, XRD and¹H-NMR showed FHFA-G and Th⁴⁺Are bonded together by metal bonds, and FHFA-GTh and Hg²⁺Bound together by a cation-pi. FHFA-G and Th were found in SEM and TEM⁴⁺And FHFA-GTh and Hg²⁺Do interact with each other and cause changes in the microscopic morphology of the product. Through the discovery of mechanism research, FHFA-G can be combined with Th⁴⁺Interacting to form supermolecular polymer metal gel FHFA-GTh and realizing Th⁴⁺Selective ultrasensitive fluorescence detection. FHFA-G and Th⁴⁺The metal gel FHFA-GTh formed by interaction has aggregation-induced emission characteristic and can realize Hg²⁺Selective ultrasensitive fluorescence detection (FIG. 8)

Based on the mechanism, the supramolecular polymer hydrogel based on the tripodal gelator, prepared by the invention, can be used for adsorbing Th in water⁴⁺And Hg²⁺And can also be used for preparing Th⁴⁺And Hg²⁺A responsive smart luminescent material. Therefore, the supramolecular polymer hydrogel has very important significance in the field of ultrasensitive response of ions.

Drawings

FIG. 1 shows the change of fluorescence intensity of FHFA-G with temperature during gelationSpectrum (λ _ex = 370nm）。

FIG. 2 is a graph showing the fluorescence response of FHFA-G to different metal ions.

FIG. 3 shows FHFA-G vs Th⁴⁺Fluorescence titration and minimum detection limit of (a)λ _ex = 370nm）。

FIG. 4 is a graph showing the change of fluorescence intensity of FHFA-GTh with temperature during gelation process (λ _ex = 370nm）。

FIG. 5 is a graph of the fluorescence response of FHFA-GTh to different metal ions.

FIG. 6 shows FHFA-GTh vs Hg²⁺Fluorescence titration and minimum detection limit of (a)λ _ex = 370nm）。

FIG. 7 shows FHFA-G vs Th⁴⁺And Hg²⁺Cycle detection of (1: (λ _ex = 370nm）。

FIG. 8 shows FHFA-G vs Th⁴⁺And Hg²⁺The inspection mechanism of (1).

Detailed Description

The synthesis of the gel factors FH and FA of the present invention is further illustrated by the following specific embodiments.

Example 1 Synthesis of FHFA-G

(1) Synthesis of guest gelator FA: trimesoyl chloride (0.2655 g, 1.0 mmol) was added to DMF (10 mL) and stirred at room temperature to dissolve it sufficiently; to another portion of DMF (10 mL) was added 4-aminopyridine (0.3106 g, 3.3 mmol) and stirred at room temperature to dissolve it thoroughly; the DMF solution containing 4-aminopyridine dissolved therein was poured into a round-bottomed flask, triethylamine (1 mL) was added as a catalyst, and the DMF solution containing trimesoyl chloride was slowly dropped into the round-bottomed flask with a constant pressure dropping funnel while stirring at room temperature for 24 hours. After the reaction was completed, the product was recrystallized to obtain 0.3943g of TA by mass and the yield was 90%. The synthetic formula of FA is shown as follows:

characterization data for FA are as follows:¹H NMR (400 MHz，DMSO-d ₆)，δ/ppm：10.98 (s，3H)，8.79-8.75 (t，J = 8.6 Hz，6H)，8.55-8.52 (t，J = 5.4 Hz, 6H)，7.84-7.82 (t，J = 4.4 Hz，6H)。¹³C NMR (151 MHz，DMSO-d ₆)，δ/ppm：166.05，165.66，150.87，150.78，146.26，146.13，145.41，135.38，134.92，132.15，131.03，114.60，109.24。HRMS：m/z [TA + H]⁺calcd for C₂₄H₁₉N₆O₃，439.1519；found 439.1515.

(2) synthesis of the subject gel factor FH: trimesoyl chloride (0.2655 g, 1.0 mmol) was weighed into dichloromethane (10 mL) and stirred at room temperature to dissolve completely. Isoniazid (0.4526 g, 3.3 mmol) was added to a fresh portion of dichloromethane (20 mL) and stirred at room temperature to dissolve it completely. The DMF solution in which isoniazid was dissolved was poured into a round-bottomed flask, and the DMF solution in which trimesoyl chloride was dissolved was slowly dropped into the round-bottomed flask using a constant pressure dropping funnel while stirring at room temperature for 24 hours. After the reaction was completed, the product was recrystallized, and the obtained FH had a mass of 0.5521g and a yield of 92%. The synthetic formula of FH is as follows:

characterization data for FH is as follows:¹H NMR (400 MHz，DMSO-d ₆)，δ/ppm：11.03-11.01 (d，J = 10.4 Hz，6H)，8.74-8.73 (m，9H)，7.78-7.77 (m，6H)。¹³C NMR (151 MHz，DMSO-d ₆), δ/ppm：165.16，164.55，164.50，150.64，140.13，138.94，133.73，130.37，121.97，121.91。HRMS：m/z [TH + Na]⁺ calcd for C₂₇H₂₂N₉O₆Na，590.1512；found 590.1584.

(3) synthesis of FHFA-G: separately, weigh host gelator FH (0.01 g, 0.018 mmol) and guest gelator FA (0.0077 g, 0.018 mmol) and add to 300mL DMSO/H₂In O (1: 2, v/v), heating and shakingAnd 5-8 min, so that the host gelator FH and the guest gelator FA form the supramolecular organogel through the interaction between the host and the guest. The gel had a weak yellowish fluorescence; after FHFA-G is heated and dissolved into sol, the fluorescence of the sol is obviously enhanced.

Example 2 continuous assay for FHFA-G detection of Th⁴⁺And Hg²⁺

Adding Fe into FHFA-G³⁺，Hg²⁺，Ag⁺，Ca²⁺，Cu²⁺，Co²⁺，Ni²⁺，Cd²⁺，Pb²⁺，Zn²⁺，Cr³⁺，Mg²⁺，Ba² ⁺，Al³⁺，Eu³⁺，Tb³⁺，La³⁺And Th⁴⁺If the fluorescence of FHFA-G increases significantly and turns green, it indicates that Th is added⁴⁺. Adding Th into FHFA-G⁴⁺Rear, Th⁴⁺The reaction with FHFA-G produced a metal gel FHFA-GTh. Then adding Fe into the metal gel FHFA-GTh³⁺，Hg²⁺，Ag⁺，Ca²⁺，Cu²⁺，Co²⁺，Ni²⁺，Cd²⁺，Pb²⁺，Zn²⁺，Cr³⁺，Mg²⁺，Ba²⁺，Al³⁺，Eu³ ⁺，Tb³⁺，La³⁺The aqueous solution, when the fluorescence of the gel is reduced again and returns to the original fluorescence state, indicates that Hg is added² ⁺。

Example 3 preparation of erasable Smart luminescent Material

A volume of 400 μ L of the supramolecular polymer hydrogel FHFA-G was prepared, and the gel was melted by heating, poured uniformly onto a clean glass plate, cooled at room temperature and air dried to form a gel film with weak yellowish fluorescence. Dipping appropriate amount of Th with fine hair pen⁴⁺The aqueous solution was uniformly applied to the gel film, which was observed to exhibit green fluorescence under a 365nm fluorescent lamp. Then, a fine hair pen is used for dipping a proper amount of Hg²⁺The aqueous solution is uniformly coated on a gel film with green fluorescence, and the fluorescence of the gel is obviousFaded and turned into a pale yellow color. The results show that the gel film prepared based on FHFA-G can conveniently, quickly and efficiently detect Th in the environment⁴⁺And Hg^2+-Moreover, the gel film can also be used as an erasable intelligent luminescent material.

Example 4, FHFA-G and FHFA-GTh on Th in aqueous solution⁴⁺And Hg²⁺Adsorption and separation of

A portion of FHFA-G (0.001G) of xerogel powder was weighed into the container containing Th⁴⁺In an aqueous solution of (5 mL, 1X 10)^- ⁴mol/L). A portion of FHFA-GTh (0.001 g) of xerogel powder was weighed into the Hg-containing solution²⁺In an aqueous solution of (5 mL, 1X 10)^- ⁴mol/L). Both were stirred at room temperature for 24 hours, centrifuged in a centrifuge for 10 minutes (1000 r/min), and the supernatant was collected. The dry gel powder pair Th of FHFA-G can be known by the analysis of the inductively coupled plasma technology⁴⁺The adsorption rate of (A) is 99.20-99.82%. Dry gel powder pair Hg of FHFA-GTh²⁺The adsorption rate of the adsorbent is 99.25 to 99.95%. Elucidation of Th in FHFA-G Dry gel powder vs aqueous solution⁴ ⁺And Hg in FHFA-GTh dry gel powder to aqueous solution²⁺Has better adsorption and separation capability.

Claims

1. Double-tripodal gelator-based supramolecular polymer hydrogel for identifying Th⁴⁺The application of (2), which is characterized in that: addition of Fe to supramolecular polymer hydrogels³⁺，Hg²⁺，Ag⁺，Ca²⁺，Cu²⁺，Co²⁺，Ni²⁺，Cd²⁺，Pb²⁺，Zn²⁺，Cr³⁺，Mg²⁺，Ba²⁺，Al³⁺，Eu³⁺，Tb³⁺，La³⁺And Th⁴⁺Aqueous solution of (2) only Th⁴⁺The addition of the compound can obviously enhance the fluorescence of the supramolecular polymer hydrogel and change the supramolecular polymer hydrogel into green;

the tripodal gelator-based supramolecular polymer hydrogel takes a reaction product of trimesoyl chloride and 4-aminopyridine as a guest gelator, and trimesoyl chloride and iso-pyridineReaction product of niacinamide as main gel factor in DMSO/H₂And the supermolecular polymer hydrogel is formed by the interaction of a host and a guest in an O system.

2. The method of claim 1, wherein Th is identified by the use of the supramolecular polymer hydrogel based on the bipod gelator⁴⁺The application of (2), which is characterized in that: in the supramolecular polymer hydrogel based on the tripodal gelator, the molar ratio of the host gelator to the guest gelator is 1: 1-1: 3; host gelator and guest gelator in DMSO/H₂The mass volume of the O system is 30-70 mg/mL; DMSO/H₂In the O system, DMSO and H₂The volume ratio of O is 1: 1.5-1: 2.5.

3. Double-tripodal gelator-based supramolecular polymer hydrogel continuously recognizing Th⁴⁺And Hg²⁺The application of (2), which is characterized in that: addition of Fe to supramolecular polymer hydrogels³⁺，Hg²⁺，Ag⁺，Ca²⁺，Cu²⁺，Co²⁺，Ni²⁺，Cd²⁺，Pb²⁺，Zn²⁺，Cr³⁺，Mg²⁺，Ba²⁺，Al³⁺，Eu³⁺，Tb³⁺，La³⁺And Th⁴⁺Aqueous solution of (2) only Th⁴⁺Can make the fluorescence of the supermolecular polymer hydrogel obviously enhanced and changed into green and Th⁴⁺The metal gel generated by the action of the supramolecular polymer hydrogel has the aggregation-induced luminescence characteristic; adding Fe to the metal gel³⁺，Hg²⁺，Ag⁺，Ca²⁺，Cu²⁺，Co²⁺，Ni²⁺，Cd²⁺，Pb²⁺，Zn² ⁺，Cr³⁺，Mg²⁺，Ba²⁺，Al³⁺，Eu³⁺，Tb³⁺，La³⁺Aqueous solution of Hg only²⁺The fluorescence of the metal gel can be weakened again and recovered to the original fluorescence state;

the supramolecular polymer hydrogel based on the tripodal gelator isTaking a reaction product of trimesoyl chloride and 4-aminopyridine as a guest gelator, taking a reaction product of trimesoyl chloride and isoniazid as a host gelator and adding the host gelator into DMSO/H₂And the supermolecular polymer hydrogel is formed by the interaction of a host and a guest in an O system.

4. The method of claim 3, wherein the double tripodal gelator based supramolecular polymer hydrogel continuously recognizes Th⁴⁺And Hg²⁺The application of (2), which is characterized in that: in the supramolecular polymer hydrogel based on the tripodal gelator, the molar ratio of the host gelator to the guest gelator is 1: 1-1: 3; host gelator and guest gelator in DMSO/H₂The mass volume of the O system is 30-70 mg/mL; DMSO/H₂In the O system, DMSO and H₂The volume ratio of O is 1: 1.5-1: 2.5.

5. Double-tripodal gel factor-based supramolecular polymer hydrogel xerogel powder for adsorbing Th in water⁴⁺And Hg²⁺The method is characterized in that: the tripodal gelator-based supramolecular polymer hydrogel takes a reaction product of trimesoyl chloride and 4-aminopyridine as a guest gelator, takes a reaction product of trimesoyl chloride and isoniazid as a host gelator, and is prepared in DMSO/H₂And the supermolecular polymer hydrogel is formed by the interaction of a host and a guest in an O system.

6. The use of the supramolecular polymer hydrogel xerogel powder based on bipatriplex gel factors for absorbing Th in water as claimed in claim 5⁴⁺And Hg²⁺The method is characterized in that: in the supramolecular polymer hydrogel based on the tripodal gelator, the molar ratio of the host gelator to the guest gelator is 1: 1-1: 3; host gelator and guest gelator in DMSO/H₂The mass volume of the O system is 30-70 mg/mL; DMSO/H₂In the O system, DMSO and H₂The volume ratio of O is 1: 1.5-1: 2.5.

7. Based on twoApplication of supramolecular polymer hydrogel of tripodal gelator in preparation of Th⁴⁺And Hg²⁺Responsive smart luminescent material, characterized in that: the tripodal gelator-based supramolecular polymer hydrogel takes a reaction product of trimesoyl chloride and 4-aminopyridine as a guest gelator, takes a reaction product of trimesoyl chloride and isoniazid as a host gelator, and is prepared in DMSO/H₂And the supermolecular polymer hydrogel is formed by the interaction of a host and a guest in an O system.

8. Use of the ambitripodal gelator based supramolecular polymer hydrogels as claimed in claim 7 for the preparation of Th⁴⁺And Hg²⁺Responsive smart luminescent material, characterized in that: in the supramolecular polymer hydrogel based on the tripodal gelator, the molar ratio of the host gelator to the guest gelator is 1: 1-1: 3; host gelator and guest gelator in DMSO/H₂The mass volume of the O system is 30-70 mg/mL; DMSO/H₂In the O system, DMSO and H₂The volume ratio of O is 1: 1.5-1: 2.5.