Method and device for detecting pentachlorophenol and sodium salt thereof in air of workplace

Abstract

The invention discloses a method and a device for detecting pentachlorophenol and sodium salt thereof in air of a workplace, and belongs to the technical field of air analysis and detection. The method for detecting the pentachlorophenol and the sodium salt thereof in the air of the workplace comprises the following steps: S01, sampling the air; s02, carrying out derivatization pretreatment and extraction; s03, loading a sample, and carrying out GC-MS detection; s04, drawing a standard curve; and S05, calculating the content of pentachlorophenol and the sodium salt thereof in the air of the workplace according to the detection result obtained in the step S03 and the standard curve obtained in the step S04. According to the method for detecting the pentachlorophenol and the sodium salt of the pentachlorophenol in the air of the workplace, the quantitative concentration can reach 0.02 mg / m < 3 > (by collecting 15L of an air sample), and the lower quantitative concentration can be reached; the adding standard recovery rate is 96-98%, and the correlation coefficient in the range of 0-10mg / L is greater than or equal to 0.999. According to 0.3 mg / m < 3 > of pentachlorophenol and sodium salt thereof OELs (PC-TWA), the method can be used for detecting pentachlorophenol and sodium salt thereof at the concentration level above the contact grade I.

Description

Technical Field

[0001] The invention belongs to the technical field of detection and analysis, and particularly relates to a method and a device for detecting pentachlorophenol and its sodium salt in the air of a workplace. Background Art

[0002] Pentachlorophenol (PCP) and its sodium salt are organochlorine compounds that have been widely used in wood preservatives, insecticides, fungicides and herbicides. However, due to its potential harm to the environment and human health, many countries have restricted or banned the use of PCP.

[0003] CN106841416A discloses a method for detecting sodium pentachlorophenol residue and its application. The sample is solid powder, and the sodium pentachlorophenol residue in the sample is extracted by sulfuric acid and n-hexane. CN113406217A discloses a method for detecting and analyzing the content of trichlorophenol, pentachlorophenol and thiochlorophenol in soap. CN101629937A discloses a quantitative detection method for pentachlorophenol in soil. The inventive method comprises the following steps: a) adjusting the pH value of the soil sample to be tested so that pentachlorophenol precipitates in molecular form; b) adding an extractant and n-hexane to the sample to extract pentachlorophenol into the extractant; c) adding an adsorbent to the extract to purify the extract; d) detecting pentachlorophenol in the extract by liquid chromatography. CN115508470A discloses a method for detecting pentachlorophenol content in milk powder, which comprises the following steps: taking milk powder as the research object, using alkaline aqueous solution and acetonitrile as extractants, extracting under water bath heating and ultrasonic conditions, enriching and purifying the extract with a C18 solid phase extraction column with uncapped filler after adjusting the pH value, blowing the eluent with nitrogen, re-dissolving it with acidified methanol-water solution, and detecting it with LC / MS-IT-TOF. The implementation steps are as follows: preparing a standard solution; preparing a sample, and dissolving the sample with hot water, extracting with solvent mixing, and salting out to obtain an extract; using an Agilent ZORBAX Eclipse XDB-C18 chromatographic column as an analytical column, a methanol-acetonitrile-ammonium acetate ternary mobile phase, a column temperature of 30°C, a flow rate of 1.0mL / min, a detection wavelength of 300nm, and quantifying by an external standard method. The national standard currently adopted for the concentration detection of pentachlorophenol and sodium pentachlorophenol, occupational disease hazard factors in workplace air, is "GBZ / T300.93-2017 Determination of Toxic Substances in Workplace Air Part 93: Pentachlorophenol and Sodium Pentachlorophenol". This standard uses high performance liquid chromatography for qualitative and quantitative analysis of pentachlorophenol and sodium pentachlorophenol. The minimum detection concentration in the solution is 0.04 mg / L. Based on the collection of 15L air sample, the minimum detection concentration is 0.03 mg / m 3When interfering substances are present in the workplace air, the occupational exposure limits of pentachlorophenol and sodium pentachlorophenol are very low (the time-weighted average allowable concentration PC-TWA of the occupational exposure limit of pentachlorophenol and sodium pentachlorophenol is 0.3 mg / m 3 ), and the HPLC method only uses retention time for qualitative analysis, and the qualitative and quantitative analysis of HPLC is very susceptible to interference. Therefore, a detection instrument method with strong anti-interference ability and lower detection limit is needed. Summary of the invention

[0004] In view of the above problems, the present invention proposes a method for detecting pentachlorophenol and its sodium salt in the air of a workplace.

[0005] The first aspect of the present invention is to disclose a method for detecting pentachlorophenol and its sodium salt in workplace air, comprising the following steps:

[0006] S01, air sampling;

[0007] S02, derivatization pretreatment, extraction;

[0008] S03, loading samples and performing GC-MS detection;

[0009] S04, draw a standard curve;

[0010] S05. Calculate the content of pentachlorophenol and its sodium salt in the workplace air based on the test results obtained in S03 and the standard curve obtained in S04.

[0011] In some embodiments of the present invention, in S01, air is absorbed by the absorption liquid after passing through the microporous filter membrane to obtain a sample solution;

[0012] Preferably, the absorption liquid is ethylene glycol; more preferably, it is a 1-5% (w / v) ethylene glycol solution of 2,4-dinitrophenylhydrazine. Compared with pure ethylene glycol, the sample can be stored for up to 3 days and does not have to be processed within 12 hours, that is, the stability of the collected sample is significantly improved. The effect is best when the concentration of 2,4-dinitrophenylhydrazine is about 3%, and the effect is not obvious when it is lower than 1%.

[0013] Preferably, the air sample is collected at a flow rate of 0.5-1.5 L / min for 10-20 minutes. When the flow rate is lower than 0.5 L / min, especially below 0.2 L / min, not only the sampling time is long, the sampling efficiency is low, the error of parallel sampling is large, and the measured display value is significantly lower than the actual substance content in the air.

[0014] In some embodiments of the present invention, S02 includes steps S21 and S22;

[0015] Wherein, in S21, the inner wall of the container is washed with the sample solution, transferred, and fixed to a fixed volume; if there are solid particles in the sample solution, filtering is performed; preferably, filtering is performed using a syringe filter;

[0016] Among them, in S22, the sample solution of S21 is mixed with potassium carbonate solution and oscillated to release pressure; an extraction solvent and a derivatizing agent are added, and the oscillation is continued after the pressure is released by oscillation; preferably, the extraction solvent is n-hexane, and the derivatizing agent is acetic anhydride.

[0017] In some embodiments of the present invention, in S21, the volume is adjusted to 5-15 mL;

[0018] S22 is mixed with 20-40 mL of 0.05-0.15 mol / L potassium carbonate solution; 1-5 mL of extraction solvent and 1-3 mL of derivatizing agent are added;

[0019] Preferably, S01 further includes the steps of washing the sampling device with ethylene glycol and collecting and merging;

[0020] Preferably, in S02, the oscillation to release the pressure is manual oscillation to release the pressure; and the continued oscillation is oscillating the sample solution at a speed of 200-400 rpm for 20-40 min using a cyclotron oscillator.

[0021] In some embodiments of the present invention, in S03, the solution is allowed to stand until the layers are separated, and the extractant layer solution is pipetted into a sampling vial.

[0022] In some embodiments of the present invention, in S03, the GC conditions are:

[0023] Chromatographic column: DB-5MS column length 30m diameter 0.25mm film thickness 0.25um

[0024] Carrier gas flow rate: 1mL / min

[0025] Injection method: splitless

[0026] Injection volume: 1 μL

[0027] Injection time: open valve after 1min

[0028] Inlet temperature: 260°C

[0029] GC-MS connector temperature: 300°C

[0030] Heating program: Initial temperature 70℃, maintain for 1min

[0031] Raise the temperature at 20°C / min to 310°C and hold for 1 min;

[0032] The MS conditions are:

[0033] Ion source temperature: 250°C

[0034] Mass spectrometer interface temperature: 290°C

[0035] Solvent delay: 2min

[0036] Acquisition mode: SIM (quantitative ion 266, qualifier ions 268, 306, 308).

[0037] In some embodiments of the present invention, in S04, the concentrations of the standard series of pentachlorophenol solutions are 0, 0.05 mg / L, 0.25 mg / L, 0.5 mg / L, 2 mg / L, 5 mg / L and 10 mg / L, respectively.

[0038] The second aspect of the present invention is to disclose a detection device for pentachlorophenol and its sodium salt in the air of a workplace, comprising:

[0039] An air sampling device is used to sample air and obtain a sample solution;

[0040] A pretreatment device, used for converting pentachlorophenol and its sodium salt in the sample solution into pentachlorophenol potassium salt, and then deriving it into a non-polar derivative using a derivatization reagent;

[0041] An extraction device, used for extracting the pretreated non-polar derivative;

[0042] and, gas chromatography-mass spectrometry.

[0043] In some embodiments of the present invention, the air sampling device includes a small sampling clamp with a microporous filter membrane installed in series and a large bubble absorption tube filled with ethylene glycol.

[0044] In some embodiments of the present invention, the chromatographic column of the gas chromatography is DB-5MS, preferably with a column length of 30m, a diameter of 0.25mm, and a film thickness of 0.25um.

[0045] In the present invention, the mass volume percentage (w / v) represents the mass g of the solute contained in every 100 mL.

[0046] Beneficial effects:

[0047] The method for detecting pentachlorophenol and its sodium salt in the workplace air of the present invention can achieve a quantitative concentration of 0.02 mg / m 3 (Based on the collection of 15L air sample), a lower quantitative concentration can be achieved; the spike recovery rate is 96% to 98%, and the correlation coefficient in the range of 0 to 10mg / L is ≥ 0.999. According to the OELs of pentachlorophenol and its sodium salt (PC-TWA) 0.3mg / m 3 This method can detect pentachlorophenol and its sodium salt at concentration levels above exposure level I.

[0048] The sampling and sample preparation method of the detection method of pentachlorophenol and its sodium salt in the workplace air of the present invention has good uniformity and good stability. The GC and MS conditions of the detection method of pentachlorophenol and its sodium salt in the workplace air of the present invention have good separation effect, good peak shape, strong anti-interference ability, fast peak time and short detection time. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a GC / MS analysis chromatogram of pentachlorophenol and its sodium salt derivative according to one embodiment of the present invention;

[0050] Figure 2 The figure is a GC / MS analysis mass spectrum of pentachlorophenol and its sodium salt derivative according to one embodiment of the present invention.

[0051] Figure 3 The pentachlorophenol and its sodium salt of Comparative Example 1 were analyzed by chromatogram without using the derivatization method. DETAILED DESCRIPTION

[0052] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0053] Unless otherwise specified, the examples and comparative examples are parallel tests with the same parameters such as components, component contents, preparation steps, preparation parameters, and dimensions.

[0054] Example 1

[0055] The method for detecting pentachlorophenol and its sodium salt in the air of the workplace comprises the following steps:

[0056] (1) Air sampling: At the sampling point, a small sampling clamp (in front) equipped with a microporous filter membrane and a large bubble absorption tube filled with 5 mL of ethylene glycol were connected in series to collect air samples for 15 min at a flow rate of 1.0 L / min.

[0057] (2) Derivatization pretreatment:

[0058] a. Wash the inner wall of the air inlet pipe three times with the sample solution in the absorption tube, transfer the sample solution into a stoppered test tube, wash the absorption tube and filter membrane with ethylene glycol, add the washing solution into the stoppered test tube, and make up to 10mL, shake well, and prepare for measurement (if there are solid particles in the sample solution, filter it with a syringe filter before measurement).

[0059] b. Add 30 mL of 0.1 mol / L potassium carbonate solution to a stoppered test tube with the sample solution to a volume of 10 mL and shake by hand to release the pressure. After completion, add 5 mL of n-hexane and 1.5 mL of acetic anhydride, shake by hand to release the pressure, and then shake the sample solution at 300 rpm on a cyclotron for 30 minutes.

[0060] (3) Extraction and loading:

[0061] After completion, let the solution stand until it separates into layers, and pipette the n-hexane layer into a 1.5 mL injection vial. Referring to the following instrumental analysis conditions, determine the concentration of pentachlorophenol and its sodium salt in the sample solution.

[0062] a.GC conditions

[0063] Chromatographic column: DB-5MS column length 30m diameter 0.25mm film thickness 0.25um

[0064] Carrier gas flow rate: 1mL / min

[0065] Injection method: splitless

[0066] Injection volume: 1 μL

[0067] Injection time: open valve after 1min

[0068] Inlet temperature: 260°C

[0069] GC-MS connector temperature: 300°C

[0070] Heating program: Initial temperature 70℃, maintain for 1min

[0071] 20℃ / min heating to 310℃ and hold for 1min

[0072] b.MS conditions

[0073] Ion source temperature: 250°C

[0074] Mass spectrometer interface temperature: 290°C

[0075] Solvent delay: 2min

[0076] Acquisition mode: SIM (quantitative ion 266, qualitative ions 268, 306, 308)

[0077] (4) Drawing of standard curve:

[0078] Take 6 50mL colorimetric tubes and use ethylene glycol to dilute the 1000mg / L pentachlorophenol standard solution into 10mL each of 0, 0.05mg / L, 0.25mg / L, 0.5mg / L, 2mg / L, 5mg / L, and 10mg / L standard series solutions. Add 30mL of 0.1mol / L potassium carbonate solution to each solution and shake by hand to release the pressure. After completion, add 5mL of n-hexane and 1.5mL of acetic anhydride, shake by hand to release the pressure, and then use a gyroscopic oscillator to shake the sample solution at 300rpm for 30min. After completion, let it stand until the solution is layered and pipette the n-hexane layer solution into a 1.5mL injection vial. Referring to the instrument analysis conditions (3), measure the peak area of ​​each concentration of the standard series. Draw a working curve with the measured peak area as the ordinate and the corresponding pentachlorophenol concentration (mg / L) as the abscissa.

[0079] (5) Sensitivity and linearity:

[0080] The average peak areas of the standard series solutions of 0, 0.05 mg / L, 0.25 mg / L, 0.5 mg / L, 2 mg / L, 5 mg / L, and 10 mg / L were 0, 2573, 12230, 24237, 107616, 271498, and 518156, respectively. The working curve equation established by linear regression fitting was f(x)=52349.167537*x+0.000000, and the correlation coefficient was r=0.999678. The GC / MS analysis chromatogram and mass spectrum of the derivatives generated by pentachlorophenol and its sodium salt after reaction with potassium carbonate solution and derivatization with acetic anhydride are shown below. Figure 1 , Figure 2 As shown:

[0081] (6) Spike recovery rate

[0082] The results of the spike test for the three groups of low, medium and high are shown in Table 1 below:

[0083] Table 1 Spiked recovery test results

[0084]

[0085]

[0086] Comparative Example 1

[0087] According to the "Determination of Toxic Substances in Workplace Air Part 93: Pentachlorophenol and Sodium Pentachlorophenol" (GBZ / T 300.93-2017), the derivatization pretreatment of Example 1 is not used. The minimum quantitative concentration is 0.09 mg / m 3 In this standard, the analytical chromatogram of pentachlorophenol and its sodium salt is shown in Figure 3 shown.

[0088] Through the above data and information, it is found that the detection method of Example 1 of the present invention can achieve a quantitative concentration of 0.02 mg / m 3 (Based on the collection of 15L air sample), a lower quantitative concentration can be achieved; the spike recovery rate is 96% to 98%, and the correlation coefficient in the range of 0 to 10mg / L is ≥ 0.999. According to the OELs of pentachlorophenol and its sodium salt (PC-TWA) 0.3mg / m 3 This method can detect pentachlorophenol and its sodium salt at concentration levels above exposure level I. At the same time, the GC / MS analysis has a good chromatographic peak shape, and can use retention time and mass spectrum for dual qualitative analysis. The selective ion method has a strong anti-interference ability when facing complex workplace air matrices, and will also reduce the occurrence of false positive detection results, providing another idea for more accurate detection of pentachlorophenol and its sodium salt concentrations in workplace air.

[0089] The preferred specific implementation modes and embodiments of the present invention are described in detail above, but the present invention is not limited to the above implementation modes and embodiments, and various changes can be made within the knowledge scope of those skilled in the art without departing from the concept of the present invention.

Claims

1. A method for detecting pentachlorophenol and its sodium salt in workplace air, characterized in that: The following steps are involved: S01, air sampling; S02, derivatization pretreatment, extraction; S03, loading samples and performing GC-MS detection; S04, draw a standard curve; S05. Calculate the content of pentachlorophenol and its sodium salt in the workplace air based on the test results obtained in S03 and the standard curve obtained in S04.

2. The method for detecting pentachlorophenol and its sodium salt in workplace air according to claim 1, characterized in that: In S01, air is absorbed by the absorption liquid after passing through the microporous filter membrane to obtain the sample solution; Preferably, the absorption liquid is ethylene glycol; Preferably, air samples are collected at a flow rate of 0.5-1.5 L / min for 10-20 min.

3. The method for detecting pentachlorophenol and its sodium salt in the workplace air according to claim 1 or 2, characterized in that: S02 includes steps S21 and S22; Wherein, in S21, the inner wall of the container is washed with the sample solution, transferred, and fixed to a fixed volume; if there are solid particles in the sample solution, filtering is performed; preferably, filtering is performed using a syringe filter; Among them, in S22, the sample solution of S21 is mixed with potassium carbonate solution and oscillated to release pressure; an extraction solvent and a derivatizing agent are added, and the oscillation is continued after the pressure is released by oscillation; preferably, the extraction solvent is n-hexane, and the derivatizing agent is acetic anhydride.

4. The method for detecting pentachlorophenol and its sodium salt in the workplace air according to any one of claims 1 to 3, characterized in that: In S21, make up to 5-15 mL; S22 is mixed with 20-40 mL of 0.05-0.15 mol / L potassium carbonate solution; 1-5 mL of extraction solvent and 1-3 mL of derivatizing agent are added; Preferably, S01 further includes the steps of washing the sampling device with ethylene glycol and collecting and merging; Preferably, in S02, the oscillation to release the pressure is manual oscillation to release the pressure; and the continued oscillation is oscillating the sample solution at a speed of 200-400 rpm for 20-40 min using a cyclotron oscillator.

5. The method for detecting pentachlorophenol and its sodium salt in the workplace air according to any one of claims 1 to 4, characterized in that: In S03, the solution is allowed to stand until the layers are separated, and the extractant layer solution is pipetted into a sampling vial.

6. The method for detecting pentachlorophenol and its sodium salt in the workplace air according to any one of claims 1 to 5, characterized in that: In S03, the GC conditions are: Chromatographic column: DB-5MS column length 30m diameter 0.25mm film thickness 0.25um Carrier gas flow rate: 1mL / min Injection method: splitless Injection volume: 1 μL Injection time: open valve after 1min Inlet temperature: 260°C GC-MS connector temperature: 300°C Heating program: Initial temperature 70℃, maintain for 1min Raise the temperature at 20°C / min to 310°C and hold for 1 min; The MS conditions are: Ion source temperature: 250°C Mass spectrometer interface temperature: 290°C Solvent delay: 2min Acquisition mode: SIM (quantitative ion 266, qualifier ions 268, 306, 308).

7. The method for detecting pentachlorophenol and its sodium salt in the workplace air according to any one of claims 1 to 6, characterized in that: In S04, the concentrations of the standard series of pentachlorophenol solutions are 0, 0.05 mg / L, 0.25 mg / L, 0.5 mg / L, 2 mg / L, 5 mg / L and 10 mg / L, respectively.

8. A device for detecting pentachlorophenol and its sodium salt in the air of a workplace, characterized in that: include: An air sampling device is used to sample air and obtain a sample solution; A pretreatment device, used for converting pentachlorophenol and its sodium salt in the sample solution into pentachlorophenol potassium salt, and then deriving it into a non-polar derivative using a derivatization reagent; An extraction device, used for extracting the pretreated non-polar derivative; and, gas chromatography-mass spectrometry.

9. The device for detecting pentachlorophenol and its sodium salt in the workplace air according to claim 8, characterized in that: The air sampling device comprises a small sampling clamp with a microporous filter membrane installed in series and a large bubble absorption tube filled with ethylene glycol.

10. The device for detecting pentachlorophenol and its sodium salt in workplace air according to claim 8, characterized in that: The chromatographic column of the gas chromatograph is DB-5MS, preferably with a column length of 30 m, a diameter of 0.25 mm, and a film thickness of 0.25 um.

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