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HJ 739-2015Ambient air. Determination of nitroaromatics. Gas chromatography mass spectrometry (English PDF)

环境空气硝基苯类化合物的测定气相色谱-质谱法

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Issued by

Ministry of Ecology and Environment

Level / Type

National · Mandatory

Issue date

February 7, 2015

Implementation date

April 1, 2015

Scope

HJ 739-2015 is the English-translated version of 环境空气硝基苯类化合物的测定气相色谱-质谱法.

HJ 739-2015 — This standard specifies the determination of gaseous nitrobenzene compounds in ambient air by gas chromatography-mass spectrometry. This standard applies to the determination of nitrobenzene, nitrotoluene and nitrochlorobenzene in ambient air and unorganized emissions.

When the sample volume is 22.5 L, nitrobenzene, p-nitrotoluene, m-nitrotoluene, o-nitrotoluene, p-nitrochlorobenzene, the detection limit of m-nitrochlorobenzene and o-nitrochlorobenzene was 0.001 mg/m3 and the lower limit was 0.004 mg/m3.

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Document preview — HJ 739-2015

National Standard of the People's Republic of China

ICS: 13.040.20
Classification: Z 15

Issued by: Ministry of Ecology and Environment

Preface
1 Scope of application
2 Normative reference documents
3 Principle of the method
4 Reagents and materials
5 Instruments and equipment
6 Sample
7 Analysis steps
8 Results are calculated and expressed
9 Precision and accuracy
Quality assurance and quality control
11 Waste treatment
Appendix A (informative) Targets for the determination of reference parameters
Appendix B (informative) method of precision and accuracy

Foreword

In order to implement the Environmental Protection Law of the People's Republic of China and the Law of the People's Republic of China on the Prevention and Control of Atmospheric Pollution, Health, regulate the ambient air nitrobenzene monitoring methods, the development of this standard.

This standard specifies the gas chromatographic-mass spectrometric method for the determination of gaseous nitrobenzenes in ambient air and unorganized emissions.

This standard is the first release.

Appendix A and Appendix B of this standard are informative.

This standard is organized by the Ministry of Environmental Protection Science and Technology Standards Division.

The main drafting unit of this standard. Tianjin Environmental Monitoring Center.

The standard verification unit. National Environmental Protection Odor Pollution Control Key Laboratory, Tianjin Hexi District Environmental Monitoring Station, Ministry of Agriculture Environment Protection of scientific research and testing, Tianjin Tanggu District Environmental Monitoring Station, Tianjin Dongli District Environmental Monitoring Station, Tianjin Dagang District Environmental Monitoring Station.

This standard is approved by the Ministry of Environmental Protection on February 7, 2015.

This standard is implemented as of April 1, 2015.

This standard is explained by the Ministry of Environmental Protection.

Determination of nitrobenzene compounds in ambient air Gas chromatography - mass spectrometry WARNING. The reagents and standard solutions used in the experiment are volatile, and the process should be carried out in the fume hood.

Line, according to the provisions of the requirements of wearing protective equipment, to avoid contact with the skin.

1 Scope of application

This standard specifies the determination of gaseous nitrobenzene compounds in ambient air by gas chromatography-mass spectrometry.

This standard applies to the determination of nitrobenzene, nitrotoluene and nitrochlorobenzene in ambient air and unorganized emissions.

2 Normative reference documents

The contents of this standard refer to the terms of the following documents. For those who do not specify a date, the valid version applies to this standard.

Technical Guidelines for Sampling of Semi - Volatile Organic Compounds in Ambient Air Technical Guidelines for Unorganized Emissions Monitoring of Air Pollutants Technical specification for manual monitoring of ambient air quality

3 Principle of the method

Using silica gel sampling tube to collect ambient air and non-organized emissions of nitrobenzene compounds in the exhaust, with dichloromethane ultrasonic solution Suction, by gas chromatography - mass spectrometry separation, detection. According to the retention time and mass spectrometry qualitative, internal standard method quantitative.

4 Reagents and materials

Unless otherwise stated, analytical pure chemical reagents and distilled water are used in accordance with national standards.

4.1 dichloromethane (CH2Cl2). pesticide residues.

4.2 Benzene (C6H6). pesticide residues.

4.3 isooctane (C8H18). pesticide residues.

4.4 Reference materials and internal standard materials. nitrobenzene (C6H5NO2), o-nitrotoluene (C7H7NO2), m-nitrotoluene (C7H7NO2), P-nitrotoluene (C7H7NO2), m-nitrochlorobenzene (C6H4ClNO2), p-nitrochlorobenzene (C6H4ClNO2), o-nitrochlorobenzene (C6H4ClNO2), the standard material is nitrobenzene-d5, the above standard purity should not be less than 98%, dark storage.

4.5 Standard mixed stock solution. rho = 2.00 mg/ml.

0.05 g (accurate to 0.0001 g) standard (4.4), respectively, into the 25 ml volumetric flask, add 2-3 (4.2) dissolved, and then Isooctane (4.3) constant volume to the mark, shake, into the dense bottle seal, 4 °C under the closed light Save, save for one year. Can also be purchased directly to prove mixed standard solution.

24.6 Internal standard stock solution. rho = 2.00 mg/ml.

Weigh 0.05 g (accurate to 0.0001g) internal standard, into the 25 ml volumetric flask, add 2-3 drops of benzene (4.2) dissolved, and then with isooctane (4.3) constant volume to the mark, shake, into the dense bottle seal, 4 °C sealed dark preservation, the preservation period of one year.

Can also be purchased directly to the standard solution.

4.7 Tuning standard stock solution. rho = 50 µg/ml.

The commercially available decaphenylphosphine (DFTPP) was added to a 10.0 ml brown volumetric flask containing an appropriate amount of dichloromethane (4.1) Diluted with dichloromethane (4.1) to 50 µg/ml and stored frozen.

4.8 Standard intermediate solution. rho =.200 mg/L.

Take the 1.00 ml nitrobenzene standard mixed stock solution (4.5) in a 10 ml volumetric flask to prepare dichloromethane (4.1) as the solvent mixture standard use of liquid, which nitrobenzene compounds concentration of.200 mg/L, in the refrigerator 4 °C conditions can be dense Keep away from light for six months.

4.9 internal standard solution. rho =.200 mg/L.

Take 1.00 ml of nitrobenzene-d5 standard stock solution (4.6) in a 10 ml volumetric flask with methylene chloride (4.1) Scale preparation of the concentration of.200 mg/L of the internal standard liquid, 4 °C conditions can be sealed under the protection of light for six months.

4.10 standard working solution. the nitrobenzene standard intermediate solution (4.8) with dichloromethane (4.1) prepared into several different concentrations the standard working solution, the internal standard concentration for the standard working curve of the middle point, is now with the distribution.

4.11 Silica Sampling Tube. Buy commercially available Silica Sampling Tube, Silicone Sampling Tube Size 20cm long, 6mm OD Diameter 4 mm, the tube is equipped with two 40 mesh silica gel, the former 150 mg, the latter 75 mg, the middle with 2 mm glass wool separated, Two layers of silica gel are silted with silanized glass wool and filled at both ends.

4.12 Helium. ultra-pure cylinder gas (purity >= 99.999%)

5 Instruments and equipment

5.1 Gas Chromatography-Mass Spectrometer. with capillary column shunt/splitless inlet, with constant current or constant voltage function, programmable temperature, with EI source and chemical workstation.

5.2 Atmospheric Sampler. Sampling flow rate can reach 0.1 ~ 1.0 L/min, flow accuracy ± 1%.

5.3 Ultrasonic cleaner. Power 250 W.

5.4 Analysis of balance. accuracy of 0.0001g.

5.5 Columns. 60 mx0.32 mm, 1.0 m film thickness (100% dimethylpolysiloxane column), other equivalent or Tested capillary column.

5.6 capacity bottle. 25 ml, 10 ml.

5.7 Microinjector. 100 l, 50 l, 10 l.

5.8 General laboratory equipment and equipment commonly used.

36 Samples

6.1 Collection of samples refer to HJ/T 55 for distribution, and adjust the flow rate of the atmospheric sampler before sampling (correction method according to HJ/T 194 and HJ 691). Sampling open the silicone sampling tube at both ends of the seal, connected with the sampler immediately after sampling. Mining Sample flow rate of 0.5 L/min, collected at least 45 min. After sampling the silica gel sampling tube immediately sealed with a sealed cap, with reference to HJ 691 on the present the samples were recorded in a laboratory with a desiccant and stored at 4 ° C for 7 days.

6.2 Sample pretreatment the silica gel sample tube before and after the silicone were placed in 2 ml vials were added 1.00 ml of dichloromethane (4.1), and add 1.0 µl of the internal standard intermediate solution (4.9), tighten the cap, at room temperature in the ultrasonic cleaner 20 min ultrasound (ultrasound Need to cool the water bath, the water temperature can not exceed 35 °C, to prevent solvent evaporation), cooling to room temperature, to be measured.

7 Analysis steps

7.1 Instrument analysis reference conditions

7.1.1 Gas Chromatographic Reference Conditions Inlet temperature. 250 °C; injection method. split injection, split ratio of 10. 1; oven temperature program. from 60 °C to the temperature rise rate of 10 ° C/min is raised to 220 ° C and then raised to 250 ° C at a rate of 15 ° C/min for 0.5 min;

Flow. 1.3 ml/min; Injection volume. 1.0 µl.

7.1.2 Mass Spectral Reference Conditions Scan mode. full scan or select ion scan (SCAN/SIM); scan range. 40 ~ 260 amu; ion source temperature.

230 ° C; transmission line temperature. 280 ° C; ionization energy. 70 eV; solvent delay. 8 min; electron multiplication voltage.

Voltage is consistent. The remaining parameters are set with reference to the instrument manual.

7.2 Calibration

7.2.1 Instrument performance check Before the instrument is used, the gas chromatographic mass spectrometer system must be checked for performance before and after 12 hours of operation.

Take the 1.0 µl tuning standard solution (4.7) directly into the chromatograph, the resulting DFTPP key ion abundance should meet the rules in Table 1 Standard. Otherwise it is necessary to adjust some parameters of the mass spectrometer or clean the ion source.

Table 1 Deuteryl triphenylphosphine (DFTPP) key ion and abundance standards

Mass ratio (m/z) abundance standard mass ion (m/z) abundance standard 51% of the peak of 30% to 60% of the base peak of 5% to 9% 68% less than 69% of the peak of 275% of the peak of 10% to 30% 70 less than 69 peaks of 2% 365 greater than 1% of peak 127 base peaks of 40% to 60% 441 are present and less than 443 peaks 197 is less than 1% of the base peak 442 is greater than 40% of the base peak 198 base, abundance of 100% 443 442 peak of 17% to 23%

47.2.2 Drawing of calibration curves

Take a certain amount of nitrobenzene compounds standard use of solution (4.8) in dichloromethane (4.1), the preparation of five concentration points of the standard series, the concentration of nitrobenzene compounds were 0.1,0.2,0.5,1.0,2.0 µg/ml, adding the internal standard Prepare the solution (4.9) so that the internal standard concentration is 1.0 µg/ml. Respectively, take the standard series of 1.0 µl solution into the gas chromatography - quality the spectra of the standard solutions of nitrobenzene compounds at different concentrations were obtained according to the instrument reference conditions (7.1). To head the ratio of the concentration of the labeled compound to the concentration of the internal standard compound is the abscissa, and the response value of the target compound to quantify the ion and the internal standard the ratio of the quantitative ion response value of the compound is the ordinate, the calibration curve is drawn, and the correlation coefficient of the calibration curve is >=0.990.

7.3 Sample determination the test sample (6.2) was measured in accordance with the instrument reference condition (7.1), with a micro-syringe or autosampler Sample, with the workstation to record and process data, when the sample concentration exceeds the upper limit of the curve, the sample should be diluted and then analyzed.

7.4 blank test

In the analysis of the sample at the same time, each batch of samples should be at least one laboratory blank test to blank silica sample tube instead of the sample the silica gel sampling tube is measured in the same procedure as the actual sample.

Calculation and representation of results

8.1 Qualitative analysis According to the target compound retention time (RT), fragment ion mass ratio and different ion abundance ratio.

The characteristic ions of the nitrobenzene compounds are given in Appendix A.

The retention time of the target compound in the sample is relative to the expected retention time (ie, the average retention time in the standard solution) the deviation should be controlled within ± 3%; the target fragment of the target compound in different abundance ratio and the expected value (ie, the standard solution in the broken the relative ion abundance ratio of the plate ions) should be controlled within ± 30%.

The total ion chromatogram of the target compound under the conditions specified in this standard is shown in Fig.

5-grouping peak sequence. 1-nitrobenzene-d5,2-nitrobenzene, 3-o-nitrotoluene, 4-m-nitrotoluene, 5-p-nitrotoluene, Chlorobenzene, 7-p-nitrochlorobenzene, 8-o-nitrochlorobenzene.

Fig.1 Total ion current diagram of nitrobenzene compounds

8.2 Quantitative analysis the data were collected by selective ion scanning, quantified by internal standard method, the mass concentration of the target compound in the sample was.

Calculated according to formula (1).

Vcf x= i (1)

Where. i - the concentration of component i in the sample, mg/m3;

The concentration of nitrobenzene compounds in the pre - silica gel, mg/L, was determined according to the standard curve of internal standard.

CV - sample desorption volume, ml.

V - Sampling volume of sample (under standard), L.

8.3 results show

When the result is greater than 0.1 g/m3, the three valid digits are retained; when the result is less than 0.1 mg/m3, 3 decimal places.

9 precision and accuracy 9.1 precision Six laboratories, respectively, 0.013 mg/m3, 0.050 mg/m3 and 0.500mg/m3 concentration of nitrobenzene compounds air the product was tested.

The relative standard deviations in the laboratory were 2.7% ~ 6.3%, 1.9% ~ 5.5%, 1.2% ~ 3.2%, respectively.

The relative standard deviations were. 2.1% ~ 6.0%, 0.5% ~ 3.2%, 0.9% ~ 2.9%, respectively.

6 repeatability range. 0.0013 ~ 0.0014 mg/m3, 0.0036 ~ 0.0046 mg/m3, 0.026 ~ 0.034 mg/m3.

Reproducibility limits range from 0.0014 to 0.0021 mg/m3, 0.0036 to 0.060 mg/m3, and 0.027 to 0.050 mg/m3.

9,2 Accuracy

Six laboratories were charged with an ambient air sample with a standard concentration of 0.010 mg/m3 and a spiked concentration of 0.40 mg/m3 the recoveries were as follows. ambient air 75.5% ~ 88.0%; no group Weaving emissions of 95.6% to 101%.

Details of precision and accuracy are given in Appendix B.

10 quality assurance and quality control Evaluation of desorption efficiency of silica gel sampling tubes According to the sampling method and the blank silica sampling tube sampling pump connected with a micro-syringe to take a certain amount of standard solution, the needle Directly into the silicone sampling tube into the air, slowly the standard solution into the silica gel sampling tube, 5 minutes after the pump with the disconnect (6.1) and (6.2). The sample was measured according to the instrument reference conditions (7.1), and the desorption efficiency of the target compound was determined the rate should be between 90% and 105%.

10.2 penetration test If the amount of the object to be measured in the posterior segment of the silica sample tube is greater than or equal to 10% of the amount of the preceding article, indicating a penetration, sampling.

10.3 blank

Full program blank and laboratory blank determination results should be less than the method detection limit.

10.4 continuous calibration Analysis of each batch of samples, the need to use the standard curve of the middle point for continuous calibration to assess whether the chromatographic system is normal, even Continued calibration standard concentration for the calibration curve of the intermediate point concentration, continuous calibration determination of the relative error should be less than 20%. There is automatic entry (CC) is required to be performed every 12 hours; if manual injection is performed, the initial analysis and the intermediate/final analysis step it is necessary to complete in a working day, the number of samples per batch no more than 20.

10.5 internal standard response and retention time the peak area of each internal standard characteristic ion in the sample is between -50% and 100% of the peak area of the internal standard characteristic ion in the same batch CC, the retention time of each internal standard is within ± 0.50 min of the retention time of the corresponding internal standard in CC.

10.6 parallel determination each batch of samples should be 5% parallel to the acquisition of parallel, the relative deviation of the measurement results should be within ± 15%.

10.7 Spike recovery rate each batch of samples should be 5% of the recovery rate, the scene collected parallel to the same sample, the actual sample spiked recovery rate should be 100 ± Less than 30%.

711 Waste treatment

The waste generated in the experiment should be collected collectively and regularly sent to qualified units for processing.

8 Appendix A

(Informative)

The reference parameter of the target is determined

Table A.1 shows the reference parameters for the target

Table A.1 Characteristic ions of nitrobenzene compounds

No. Compound Chinese name Compound English name CAS No. Quantitative ionic qualitative ion 1 nitrobenzene-D5 (IS) Nitrobenzene-d5 (IS) 4-165-60-0 82 54,128 2 nitrobenzene 98-95-3 77 51,123 3 o-nitrotoluene 2-Nitrotoluene 88-72-2 65 92,120 4-nitrotoluene 3-Nitrotoluene 99-08-1 91 65,137 5-p-nitrotoluene 4-Nitrotoluene 99-99-0 137 65,91 6-nitrochlorobenzene 1-Chloro-3-nitrobenzene 121-73-3 75 111,157 7-p-nitrochlorobenzene 1-Chloro-4-nitrobenzene 100-00-5 75 111,157 8 o-nitrochlorobenzene 1-Chloro-2-nitrobenzene 88-73-3 75 111,157

9 Appendix B

(Informative)

Method of precision and accuracy

Table B.1 ~ 2 are given the method of repeatability, reproducibility and spike recovery and other precision and accuracy indicators.

Record B.1 The precision of the method the target compound Precision data summary average value (Mg/m3) Laboratory relative standard Quasi-deviation RSDi (%) Inter-laboratory relative standard Quasi-deviation RSDo (%) Repetitive limit r (Mg/m3) Reproducibility R (Mg/m3) Nitrobenzene 0.010 4.2 6.0 0.0014 0.0021 0.052 3.4 3.2 0.0041 0.0060 0.510 1.1 2.9 0.0308 0.0499 P-nitrotoluene 0.010 8.4 2.6 0.0014 0.0015 0.050 2.4 2.4 0.0037 0.0048 0.510 2.3 2.4 0.0330 0.0454 M-nitrotoluene 0.010 10.1 3.7 0.0014 0.0017 0.052 1.8 3.2 0.0041 0.0060 0.515 2.0 1.9 0.0308 0.0390 O-nitrotoluene 0.010 8.3 2.7 0.0013 0.0014 0.052 2.6 2.8 0.0037 0.0053 0.515 2.9 2.7 0.0332 0.0491 P-nitrochlorobenzene 0.010 9.0 2.1 0.0014 0.0014 0.051 3.1 1.2 0.0047 0.0046 0.505 1.7 1.3 0.0319 0.0344 M-nitrochlorobenzene 0.010 7.3 3.6 0.0013 0.0015 0.052 2.0 2.6 0.0040 0.0053 0.505 2.3 1.6 0.0337 0.0384 O-nitrochlorobenzene 0.010 7.4 3.8 0.0013 0.0016 0.051 2.3 0.5 0.0038 0.0036 0.505 1.4 0.9 0.0263 0.0271 Schedule B.2 Method accuracy the target compound Accuracy data summary Sample Type Average (mg/m3) Relative error RE (%) Relative error Final RE 2SRE (%) Spike recovery Final value P 3SP (%) Nitrobenzene Ambient air 0.008 21.2 21.2 4.5 78.8 6.6 Unorganized exhaust gas 0.390 2.5 2.5 2.1 97.5 3.0 P-nitrotoluene Ambient air 0.008 19.8 19.8 3.5 80.2 5.4 Unorganized waste gas 0.392 2.1 2.1 2.0 97.9 3.0 M-nitrotoluene Ambient air 0.008 20.7 20.7 3.9 79.3 5.7 Unorganized waste gas 0.401 0.1 0.1 1.8 100.1 2.7 O-nitrotoluene Ambient air 0.008 18.5 18.5 3.8 81.5 5.7 Unorganized waste gas 0.390 2.7 2.7 2.1 97.3 3.3 P-nitrochlorobenzene Ambient air 0.008 16.9 16.9 2.9 83.1 4.5 no tissue exhaust 0.399 0.2 0.2 2.1 99.8 3.0 M-nitrochlorobenzene Ambient air 0.008 17.8 17.8 1.8 82.2 2.7 Unorganized waste gas 0.394 1.6 1.6 2.9 98.4 4.2 O-nitrochlorobenzene Ambient air 0.008 16.8 16.8 5.3 83.2 7.8 Unorganized exhaust gas 0.394 1.5 1.5 2.4 98.5 3.6

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