KR101463459B1 - Method of simultaneous analysis for formaldehyde and 1,4-dioxane using gas chromatography with mass spectrometry - Google Patents

Abstract

A method of simultaneous analysis for formaldehyde and 1,4 dioxane using gas chromatography and mass spectrometry according to the present invention includes manufacturing a derivatization preprocessing sample by adding an internal standard material, an ionic strength additive, and a derivative material coupled with an analysis material of a polarity including the sample to the sample; manufacturing a measuring micro extractor absorbing an analysis material by extracting the derivatization preprocessing sample by a micro extractor; obtaining gas chromatography of a sample by injecting the measuring micro extractor into an injection hole of a gas chromatography meter to detach the analysis material; and obtaining a weight spectrum by passing the detached measuring sample through a mass spectrometer through a capillary column, and simultaneously analyzes whether a first compound and a second compound having different boiling points due to different polarities. The present invention is faster and simpler as compared with the related art, may reduce use of a solvent and perform analysis with high accuracy.

Description

METHOD OF SIMULTANEOUS ANALYSIS FOR FORMALDEHYDE AND 1,4-DIOXANE USING GAS CHROMATOGRAPHY WITH MASS SPECTROMETRY BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for simultaneous determination of formaldehyde and 1,4-dioxane by gas chromatography and mass spectrometry,

The present invention relates to a method for simultaneously analyzing formaldehyde and 1,4-dioxane by gas chromatography and mass spectrometry, and more particularly, to a method for the simultaneous determination of formaldehyde by solid phase microextraction (SPME) (GC / MS) after use. The present invention also relates to a method for simultaneous analysis using gas chromatography / mass spectrometry (GC / MS).

1,4-dioxane is used as a stabilizer in chlorinated solvents and is used in the form of cellulose acetate, ethyl cellulose, benzyl cellulose, resins, waxes wax, oil, and spirit-sol dyes. It is also used as a solvent for adhesives, sealants, cosmetics, pharmaceuticals, rubber chemicals and surface coatings (EPA 749-F-95-010 (1995)). However, 1,4-dioxane is classified as a B2 substance by the US Environmental Protection Agency (EPA 822-R-06-013, 2006).

Formaldehyde is generated by oxidation of methane or other organic substances in the air in response to sunlight, or metabolized by microorganisms, and is naturally present in the environment. In addition, formaldehyde is also produced in water by reactions such as ozonization and chlorination. Formaldehyde is easily exposed to the environment (EPA 560 / 2-76-009, 22-80, 1976) because it is widely used in many manufacturing industries such as leather manufacturing, photographic plates, explosives, cosmetics and fungicides. The amount of formaldehyde produced by the product is much higher than the amount that is naturally occurring. According to the US Environmental Protection Agency, formaldehyde has been designated as a B1 carcinogen by exposure to inhalation exposure and has been designated as a monitoring item in Japan's water law, with a water quality standard of 80 μg / L (50 water quality standards, Tokyo Metropolitan Waterworks Bureau, Tokyo , Japan (2007)).

As mentioned above, both formaldehyde and 1,4-dioxane are substances that are highly likely to be carcinogenic and are being managed as monitoring items in water quality. Therefore, a rapid, simple and accurate analysis method has been highly demanded.

The US Environmental Protection Agency has proposed a method for analyzing volatile organic compounds including 1,4-dioxane by purge-trapping and isotope-dilution GC / MS in method 1624 and the like. However, since 1,4-dioxane has a very small K _ow value of -0.27, which is a water-octanol coefficient, its solubility in water is higher than that of other volatile organic substances, so that the extraction efficiency by organic solvent is very low, (EPA method 8260B), or the detection limit is not set or is very high (12 μg / L).

Formaldehyde has low molecular weight and low boiling point, making it difficult to separate and analyze. Standard methods 6252 and EPA Method 556, which analyze liquid samples by liquid-liquid extraction and GC / ECD, are commonly used. (Analyst, 119, 2237-2240, 1994) or reacted with dimedone (5,5-dimethylcyclohexane-1,3-dione) in a basic solution using flow injection analysis (Talanta, 58, 1271-1278, 2002). In addition, the pararosaniline method has been modified and measured by UV-VIS spectrophotometry (Anal. Chem., 53 (3), 2118-2123, 1983). 54 (11), 1739-1742, 1982), PFBHA (o) is used as an indicator of the formation of oxazolidine derivatives in the atmosphere by the method of derivatization and analyzed by FID (Flame Ionization Detector) - (pentafluorobenzyl) -hydroxylamine) and derivatives are formed and analyzed by GC / ECD or gas chromatography / mass spectrometry (GC / MS) (Kor. Soc. Food Sci. Nutr., 35 10), 1412-1419, 2006). In addition, HPLC analysis using 2,4-dinitrophenylhydrazine (DNPH) derivatization has been used as a standard method by the US Environmental Protection Agency and has also been analyzed by HS-SPME (headspace-solid phase microextraction) method J. of Chromato, A, 1210, 25-29, 2008).

These conventional analytical methods fail to simultaneously analyze compounds having different molecular weights (formaldehyde: 30, 1,4-dioxane: 88) and boiling point (formaldehyde: -19.3 ° C, 1,4-dioxane: 101 ° C) And the results are shown in Fig.

An object of the present invention is to provide a quantitative analysis method capable of analyzing substances having different polarities quickly, easily and accurately in a single analysis. In particular, it is intended to provide a method for easily and simultaneously analyzing formaldehyde and 1,4-dioxane with excellent accuracy.

In order to accomplish the above object, a simultaneous analysis method using gas chromatography and mass spectrometry according to an embodiment of the present invention is characterized in that a sample is mixed with an internal standard substance, an ion intensity enhancer, and an analyte of polarity included in the sample A derivatization step of adding a derivative material to prepare a derivatization pretreatment sample; A solid phase extraction step of extracting the derivatization pretreatment sample with a solid phase microextractor to produce a microextractor for measurement adsorbing the analytical substance; A first measuring step of injecting the measuring micro extractor into an inlet of a gas chromatography measuring instrument to desorb the analyte to obtain a gas chromatogram of the sample; And a second measurement step in which the desorbed measurement sample passes through a capillary separation tube and passes through a mass spectrometer to obtain a mass spectrum, wherein the first compound and the second compound differ in boiling point in polarity, Is included in the analysis.

The first compound and the second compound may each be formaldehyde and 1,4-dioxane. Conventionally, there has been no method of analyzing these substances at the same time, but the present inventors have experimentally confirmed that they can simultaneously qualitatively and quantitatively analyze each of them by the above-described method, and completed the present invention.

The solid-phase microextractor may be one comprising polydimethylsiloxane and divinylbenzene, or may be a fibrous solid-phase extractor composed of the same. When this solid-state micro-extractor is applied, formaldehyde and 1,4-dioxane can be suitably applied for simultaneous analysis.

The solid-phase extraction step may be a direct extraction by immersing a fibrous solid phase micro-extractor in the derivatization pretreatment sample. In the conventional solid phase extraction, the head space method is mainly used, but in the present invention, the detection intensity of the target substance is increased by the direct extraction method.

The direct extraction using the fibrous solid phase microextractor may be performed for 10 minutes to 30 minutes. In the case of direct extraction within the above-mentioned time range, the extraction efficiency does not increase even after lapse of 15 minutes of extraction time of 1,4-dioxane, so that the optimal analysis efficiency for simultaneous analysis in the time range can be increased.

 The direct extraction using the fibrous solid phase microextractor may be carried out at a temperature of 20 to 40 ° C. The temperature for simultaneous extraction of 1,4-dioxane and formaldehyde for the direct extraction in the temperature range shows the optimum analytical efficiency. In the case of 1,4-dioxane, the higher the extraction temperature, the better the efficiency. However, in the case of formaldehyde, the opposite result, that is, the efficiency is decreased.

The derivatization pretreatment sample may include a solvent, and the solvent may be a buffer solution containing an acid such as any one selected from the group consisting of hydrochloric acid, phosphoric acid, formic acid, boric acid, acetic acid, and combinations thereof May be used.

The ionic strength increasing agent included in the derivatization pretreatment sample may be any one selected from the group consisting of, for example, sodium chloride, sodium carbonate, sodium hydroxide, and combinations thereof.

The derivatization pretreatment sample may be an acidic aqueous solution. When the pre-treatment sample in the derivatization step is an acidic aqueous solution, the pH may be 2 to 6.5, and the pH may be maintained at about 5 using an acetate buffer solution or the like.

The concentration of the ionic strength increasing agent contained in the derivatization pretreatment sample may be 4 to 6 wt%. When the concentration of the ionic strength increasing agent is more than 6% by weight, the extraction efficiency of one target substance is lowered. When the concentration is less than 4% by weight, the effect of increasing the ionic strength may be insignificant. The ionic strength enhancer may preferably be sodium chloride, and the extraction efficiency of 1,4-dioxane and formaldehyde may be rather low when the concentration of sodium chloride contained in the derivatization pretreatment sample is 4 to 6 wt% .

The derivative material may be a hydrazone derivatization reaction material.

The derivative material may be 2,4-dinitrophenylhydrazine, and the 2,4-dinitrophenylhydrazine may be combined with formaldehyde to derivatize formaldehyde.

The internal standard material may be 1,4-dioxane- d ₈ .

The capillary separation tube used in the gas chromatography is a separation tube of phenylmethyl polysilicate popular, and may have a diameter of 0.2 to 0.32 mm and a length of 25 m or more.

The mobile phase gas used in the gas chromatography may be any one selected from the group consisting of nitrogen, hydrogen, helium, and combinations thereof.

The simultaneous analysis method provides a method for simultaneously detecting two materials having different polarities, for example, substances such as formaldehyde and 1,4-dioxane, and analyzing them with excellent accuracy. The dissociation constant of formaldehyde (pKa) is 13.27, the dissociation constant of 1,4-dioxane is (pKa), -2.92, the difference of dissociation constants of these is about 16.19, Or more, excellent analytical effect can be obtained.

In the simultaneous analysis method of the present invention, it is also important to select a buffer solution for simultaneously analyzing two substances having different polarity, that is, a solvent and an ionic strength increasing agent. In particular, when simultaneous analysis of 1,4-dioxane and formaldehyde is desired the buffer may be a buffer having a pH in the range of 2 to 6.5 and preferably in a buffer having a pH in the range of 4 to 6.5.

The simultaneous analysis method using gas chromatography and mass spectrometry according to the present invention can simultaneously analyze 1,4-dioxane and formaldehyde by one-time analysis, thereby making it possible to perform the analysis quickly and easily. By reducing the use of harmful extraction solvent, Environment-friendly effect can be obtained, and detection sensitivity can be increased by using a direct extraction method instead of the headspace method.

Figure 1 shows a pretreatment process for the simultaneous analysis of formaldehyde and 1,4-dioxane, which is a diagrammatic representation of sample preparation, derivatization and pretreatment [A], [B] the state of the sample before and after derivatization .
Figure 2 shows a chromatogram using [A] PDMS / DVB 65 μm fiber and [B] PDMS 100 μm fiber chromatogram.
FIG. 3 is a graph showing the relationship between the extraction time and the extraction amount of the derivatization pretreatment sample.
4 is a graph showing the relationship between the extraction temperature and the extraction amount of the derivatization pretreatment sample.
Figure 5 shows the effect of the concentration of sodium chloride contained in the derivatization pretreatment sample on extraction.
FIG. 6 is a graph showing the results of a simultaneous analysis of formaldehyde derivatives (m / z 210), 1,4-dioxane (m / z 88), 1,4-dioxane-d8 96] and [B] is a graph showing the mass spectrum of the corresponding peak.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In one embodiment of the present invention, the first compound and the second compound having different boiling points due to their polarities being the target of analysis (target material) are 1,4-dioxane and formaldehyde, respectively, Simultaneous analytical methods using chromatography and mass spectrometry are described.

The target materials 1,4-dioxane and formaldehyde (and derivatives thereof) are represented by the following formulas (1) and (2).

(B) Formaldehyde is derivatized with 2,4-dinitrophenylhydrazine represented by [A]. [Formula 1] < EMI ID = To form [C] formaldehyde-2,4-dinitrophenylhydrazone.

In order to identify and quantify 1,4-dioxane and formaldehyde derivatives in drinking water, a sample is derivatized in an acidic aqueous solution to prepare a derivatization pretreatment sample, which is extracted with a solid phase microextraction (SPME) fiber And analyzed using gas chromatography. At this time, the gas chromatography may be a column using a (5% -phenyl) -methylpolysiloxane group as a stationary phase, and a high purity helium gas may be preferably used as the mobile phase gas. In addition, the gas chromatography can be simultaneously performed by a mass spectrometer connected thereto.

Figure 1 shows a pretreatment process for the simultaneous analysis of formaldehyde and 1,4-dioxane, which is a diagrammatic representation of sample preparation, derivatization and pretreatment [A], [B] the state of the sample before and after derivatization .

Referring to FIG. 1, simultaneous analysis of formaldehyde and 1,4-dioxane, which is one embodiment of simultaneous analysis using gas chromatography and mass spectrometry of the present invention, involves (a) (B) a derivatization step of converting the polar group of the analyte into a compound suitable for gas chromatography analysis, (c) extracting with a solid phase microextractor, (d) Detecting and quantifying the content of the analyte to be eluted by introducing the analyte into the mass spectrometer, and determining the content thereof.

In the sample preparation step, 30 mL of sample may be used. Sodium chloride may be added to a concentration of 5% w / v and adjusted to pH 5 using 5M acetate buffer. 100 [micro] g of 1.4-dioxane- d 8 may be added as an internal standard substance for correcting the recovery rate of the substance. In the derivatization step, the hydrazone derivatization reaction using the 2,4-DNPH reagent can be used as the analyte. The reaction time is preferably 30 minutes at room temperature.

The capillary separation tube for gas chromatography is preferably a separation tube of (5% -phenyl) -methylpolysiloxane group having a diameter of 0.2 mm to 0.32 mm, a length of 25 m or more, and a film thickness of 0.25 to 0.33 μm, Nitrogen, hydrogen, or helium gas may be applied. As the mobile phase gas, a high purity helium gas may be preferably applied.

The analytes separated through the capillary separation tube in the detection and quantification step are set to be introduced into the mass spectrometer, wherein the detected ions are subjected to qualitative and quantitative analysis by selecting characteristic ions of the mass spectrum.

The simultaneous analysis method using gas chromatography and mass spectrometry according to the present invention provides a method for simultaneously analyzing two materials which are difficult to analyze simultaneously, and particularly, formaldehyde and 1,4-dioxane can be simultaneously qualitatively and quantitatively analyzed. The present invention can increase the accuracy of extraction while using a solid phase microextractor, and can also achieve economical environmental effects by reducing the use of harmful extraction solvent used in conventional analysis methods.

Example  1-Formaldehyde and 1,4- Dioxane  Detection experiment

1) Preparation of sample

1.5 g of sodium chloride was added to 30 mL of drinking water to make a concentration of 5% w / v, and 1.8 mL of 5 M acetate buffer was added to adjust pH to 5. To this, 100 μg of 1,4-dioxane-d8 internal standard solution was added to prepare a sample for analysis.

2) Treatment of derivative reaction

To this sample solution, 1.8 mL of 2,4-DNPH (dinitrophenyl hydrazine) at a concentration of 3 mg / mL was added, and then a magnetic bar was added and sufficiently reacted at room temperature for 30 minutes while stirring. After completion of the reaction, the 65 μm PDMS / DVB solid phase microextraction fiber was directly immersed in the sample solution, followed by extraction at 30 ° C. for 15 minutes with stirring.

3) Simultaneous detection and analysis

The extracted fiber was injected into the inlet of GC / MS and desorbed at 240 ° C for 2 minutes.

Gas chromatography-mass spectrometry (GC / MS) was carried out using Agilent's gas chromatograph, 6890N model, US LECO mass spectrometer and Pegasus III model. The analytical conditions of the gas chromatography and the mass spectrometer are shown in Table 1 below.

Gas chromatography
(Gas chromatography) Agilent 6890N (agilent, USA) column
(Column) DB-XLB (25 m x 0.2 mm x 0.33 m) Carrier gas
(Carrier Gas) He (99.9999%) at 1.2 mL / min Inlet port temperature
(Injection Port Temp.) 240 ℃ Inlet mode
(Inlet Mode) splitless Removal time
(Desorption time) 2 min Temperature control
(Temp. # Rate (° C / min) Target temp. (° C) Duration (min) One Initial 30 7 2 20 100 0 3 50 250 15 Mass spectrometer
(Mass spectrometer) Pegasus III (Leco, USA) Contact temperature
(Interface Temp.) 300 ° C Ionization mode
(Ionization Mode) Electron impact (EI) Electronic energy
(Electron energy) 70 eV Ion source temperature
(Ion source Temp.) 240 ℃ analysis
(Analyzer) Time-of-Flight Detection mode
(Detection Mode) Scan mode or extracted ion monitoring

The chromatogram and mass spectrum of the sample are shown in FIG. As shown in the chromatogram of FIG. 6, 1,4-dioxane and formaldehyde derivatives were effectively separated, and 1,4-dioxane-d8, an internal standard substance of 1,4-dioxane, But mass spectrometry confirmed that the specific masses are different from each other and can be separated.

Quantitative analysis was performed by combining the areas of the peaks in the chromatogram, and then calculating the calibration curve by applying the internal standard method.

The quantitation ion and calibration curve, recovery, precision (RSD,%), limit of detection and limit of quantitation of the analyte for qualitative and quantitative analysis are shown in Table 2 And the results of the quantitative analysis on the samples are shown in Table 3.

No Target
compound Quantitation ion (m / z) Correlation coefficient (R ² ) Recovery
(%) RSD (%) Limit of Detection (mg / L) Limit of Quantitation (mg / L) One 1,4-dioxane 88 0.998 86.6 2.57 0.017 0.051 2 Formaldehyde 210 0.996 116.6 3.44 4.4 × 10 ^-5 1.3 × 10 ^-4

Compound name Analysis sample number Number of samples Concentration range (ng / mL) Formaldehyde 15 9 0.44-4.17 1,4-dioxane 15 0 ND (not detected)

Referring to the results of Table 2 and Table 3, it was possible to detect the presence of formaldehyde and 1,4-dioxane contained in the sample with high accuracy by the simultaneous analysis method of the present invention, And the concentration of the target substance can be analyzed.

Example  2-Determination of other formaldehyde and 1,4- Dioxane  Detection experiment

1) Comparison of analysis results according to the kind of solid phase microextraction fiber

Simultaneous analysis was carried out by analyzing water containing both formaldehyde and 1,4-dioxane through a pretreatment and the like in the same manner as in Example 1 above. The other conditions were the same, but the results of gas chromatography, in which the kinds of the solid phase microextraction fibers were measured using 65 占 퐉 PDMS / DVB solid phase microextraction fiber in the same manner as in Example 1, are shown in [A] , And results of using PDMS 100 탆 fiber are shown in [B], respectively. Referring to FIG. 2, it can be seen that 65 占 퐉 PDMS / DVB solid phase microextraction fiber rather than PDMS 100 占 퐉 fiber is more suitable for detecting both formaldehyde and 1,4-dioxane.

2) Comparison of analysis results according to extraction time

Simultaneous analysis was carried out by analyzing water containing both formaldehyde and 1,4-dioxane through a pretreatment and the like in the same manner as in Example 1 above. The other conditions were the same, but the extracted amounts were compared at different extraction times in the solid phase extraction step, and the results are shown in FIG. Referring to FIG. 3, it was confirmed that the increase in the extraction amount of 1,4-dioxane was insignificant when it exceeded 15 minutes, and it was confirmed that the extraction time of less than about 15 minutes was advantageous for improving the accuracy of analysis there was.

3) Comparison of analysis results according to extraction temperature

Simultaneous analysis was carried out by analyzing water containing both formaldehyde and 1,4-dioxane through a pretreatment and the like in the same manner as in Example 1 above. The other conditions were the same, but the extracted amounts were compared at different extraction temperatures in the solid phase extraction step, and the results are shown in FIG. Referring to FIG. 4, it was confirmed that the result of extraction at about 30 ° C. is most suitable for analysis.

4) Concentration of sodium chloride ( wt %) Comparison of analysis results

Simultaneous analysis was carried out by analyzing water containing both formaldehyde and 1,4-dioxane through a pretreatment and the like in the same manner as in Example 1 above. The other conditions were all the same, but the extraction amount according to the concentration of sodium chloride contained in the derivatization pretreatment sample was compared, and the results are shown in FIG. Referring to FIG. 5, it can be seen that an example including about 5 wt% of sodium chloride is most suitable for analysis.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

Claims (15)

A derivatization step of preparing a derivatization pretreatment sample by adding an internal standard substance, an ionic strength enhancer, and a hydrazone derivatization reactant, which binds to an analyte of polarity included in the sample, to the sample;
A solid phase extraction step of extracting the derivatization pretreatment sample with a solid phase microextractor to produce a microextractor for measurement adsorbing the analytical substance;
A first measuring step of injecting the measuring micro extractor into an inlet of a gas chromatography measuring instrument to desorb the analyte to obtain a gas chromatogram of the sample; And
A second measurement step in which the desorbed measurement sample passes through a capillary separation tube and passes through a mass spectrometer to obtain a mass spectrum;
A simultaneous analytical method using gas chromatography and mass spectrometry, simultaneously analyzing whether a formaldehyde-based compound and a 1,4-dioxane-based compound differ in polarity and have different boiling points. delete The method according to claim 1,
Wherein the solid phase microextractor comprises polydimethylsiloxane and divinylbenzene. ≪ Desc / Clms Page number 19 > The method according to claim 1,
Wherein the solid phase extraction step is by direct extraction comprising immersing a fibrous solid phase micro-extractor in the derivatization pretreatment sample, using gas chromatography and mass spectrometry. 5. The method of claim 4,
Wherein the direct extraction using the fibrous solid phase microextractor is performed for 10 minutes to 30 minutes, using simultaneous gas chromatography and mass spectrometry. 5. The method of claim 4,
Wherein the direct extraction using the fibrous solid phase microextractor is performed at a temperature of 20 to 40 캜. The method according to claim 1,
Wherein the ionic strength enhancer is any one selected from the group consisting of sodium chloride, sodium carbonate, sodium hydroxide, and combinations thereof, using simultaneous gas chromatography and mass spectrometry. 8. The method of claim 7,
Wherein the concentration of sodium chloride contained in the derivatization pretreatment sample is 4 to 6% by weight. delete The method according to claim 1,
The hydrazone derivatization reaction material is 2,4-dinitrophenylhydrazine, and the 2,4-dinitrophenylhydrazine is formed by coupling with formaldehyde to derivatize formaldehyde Simultaneous analysis using gas chromatography and mass spectrometry. The method according to claim 1,
The internal standard was 1,4-dioxane - d ₈ is the gas chromatography method and the simultaneous analysis with mass spectrometry will be applied. The method of claim 3,
Wherein the capillary separation tube used in the gas chromatography has a diameter of 0.2 to 0.32 mm and a length of 25 m or more as a separation tube of phenylmethyl polysiloxane, using simultaneous gas chromatography and mass spectrometry. The method according to claim 1,
Wherein the mobile phase gas used in the gas chromatography is any one selected from the group consisting of nitrogen, hydrogen, helium, and combinations thereof, by simultaneous gas chromatography and mass spectrometry. The method according to claim 1,
Wherein the pretreatment sample in the derivatization step is an acidic aqueous solution. 15. The method of claim 14,
Wherein the acidic aqueous solution is a buffer solution having a pH value of from 2 to 6.5, using simultaneous gas chromatography and mass spectrometry.

Images