HJ 868-2017Ambient air. Determination of phthalate esters. High performance liquid chromatography (English PDF)

5.6 Anhydrous sodium sulfate (Na2SO4)

Bake in a muffle furnace at 450 °C for 4 h before use, cool, and store in sealed glass jar.

25.7 ether - n-hexane mixed solution. 1 9, Pro use now with.

5.8 ether - n-hexane mixed solution. 2 8, Pro use now.

5.9 acetone - n-hexane mixed solution. 1 9, Pro use now.

5.10 methylene chloride - n-hexane mixed solution. 2 8, Pro use now.

5.11 diphenyl phthalate (C20H14O4). purity of 98% or more.

Alternatives may also be used.

5.12 Substitute stock solution. rho =.2000 µg/ml.

Weigh about 0.1 g of diphenyl phthalate (5.11), accurate to 0.1 mg, dissolved in acetonitrile (5.5) in a 50 ml volumetric flask and set the volume, shake well. 4 °C the following sealed. Can be purchased directly from the market certified standard solution, reference standard solution certificate for preservation.

5.13 Alternative solution. rho = 80.0 µg/ml.

Pipette 1.00 ml of stock solution (5.12) into a 25 ml volumetric flask, dilute to volume with acetonitrile (5.5) and mix well. 4 °C below the dense Save sealed.

5.14 Diisobutyl phthalate Standard substance. purity 98% or more.

5.15 Diisobutyl phthalate standard stock solution. rho =.2000 µg/ml.

Weigh about 0.1 g of diisobutyl phthalate (5.14), accurate to 0.1 mg in a 50 ml volumetric flask, dissolve it in acetonitrile (5.5) Solution and set the volume, shake well. Can be purchased directly from the market certified standard solution. 4 °C the following sealed.

5.16 6 phthalates standard stock solution. rho =.2000 µg/ml.

Buy a commercially available standard solution of acetonitrile or methanol as a solvent, including dimethyl phthalate, diethyl phthalate, Dibutyl phthalate, butyl benzyl phthalate, di-2-ethylhexyl phthalate and di-n-octyl phthalate. 4 ° C the following seal preservation, or reference standard solution certificate to save.

5.17 8 phthalates standard solution. rho = 80.0 µg/ml.

Pipette 1.00 ml stock solution (5.12) and 1.00 ml phthalate standard stock solution (5.15), (5.16) in 25 ml Volumetric flask, with acetonitrile (5.5) constant volume, mix well. 4 °C the following sealed.

5.18 Magnesium silicate. 150 µm to 250 µm (100 mesh to 60 mesh). Before use, weigh 100 g ± 10 g into an evaporating dish at 140 ° C Heated 16 h, while hot transferred to 500 ml grinding mouth reagent bottle, cooled to room temperature, add 3.0 ml ± 0.1 ml experimental water, sealed, Shake well for 10 min and let stand for 2 h.

5.19 Magnesium silicate solid phase extraction column. 1000 mg/6 ml, but also according to the content of impurities to select the appropriate volume of commercial solid phase extraction column.

5.20 glass (or quartz) fiber filter. According to the sampling head to select the appropriate size of the filter. The retention of the membrane on 0.3 µm standard particles the rate of not less than 99%, air flow velocity of 0.45 m/s, leaflets filter resistance of not more than 3.5 kPa.

Before use in a muffle furnace at 400 °C heating 5 h or more, cooled, wrapped with aluminum foil, stored in a filter box, to avoid direct connection with the plastic Touch, to ensure that the filter before sampling and sampling is not stained, and in the flat before the sample is not folded state.

5.21 XAD-2 resin (styrene-divinylbenzene polymer). 250 µm to 840 µm (60 mesh to 20 mesh).

Before extraction with dichloromethane (5.1) reflux 16 h, the replacement of dichloromethane (5.1) to continue reflux extraction 16 h, then ether -N-hexane mixed solution (5.7) refluxed 16 h, vacuum dried at room temperature 2 h ~ 3 h. Keep in a clean glass bottle.

5.22 Polyurethane Foam (PUF). polyether type, with a density of 22 mg/cm3 to 25 mg/cm3, cut and grown 25 mm and 50 mm in diameter 3 is a cylinder of 45 mm to 65 mm (length, diameter is determined by the specifications of the glass sampling cartridge).

Before use, wash with experimental water, drain water, rinse three times with acetone (5.4), place into Soxhlet extractor (6.4), wash with acetone (5.4). The mixture of diethyl ether and n-hexane (5.7) was refluxed for 16 h, and the mixture was replaced with fresh ether-n-hexane solution (5.7) Reflux extraction. Room temperature vacuum drying 2 h ~ 3 h (also available nitrogen (5.23) dry). Keep it in a suitable container with aluminum foil and seal it.

5.23 Nitrogen. Purity >=99.999%.

5.24 glass wool. Before use with dichloromethane (5.1) reflux extraction 2 h ~ 4 h, dried and sealed.

7.1 Sample collection

Sample collection meets HJ 691 requirements.

Phthalates in the ambient air exist in the gas phase, particulate matter or both exist at the same time, you must also use glass (or quartz) fiber filter, XAD-2 resin and polyurethane foam collection.

Before sampling the membrane filter and glass sampling tube installed in the filter holder and the sampling sleeve, connecting the sampler, adjusting the sampling flow, the beginning sampling. Remove the filter after the sample is finished, the sample dust to the inside of the fold, remove the glass sampling tube, and fold the filter together with aluminum foil wrapped, Put in the original box sealed.

Collect the site before the sample collection blank, sealed glass sampling tube and filter membrane to the sampling site, the sampling head is not installed Sampling, and then remove the glass sampling cartridge and filter, sealed with the same sample and sealed, with the sample shipped back to the laboratory.

7.2 Sample preservation

5 After the samples were collected, the samples were refrigerated below 4 °C and extracted within 7 days. The sample extract is stored below 4 ° C and stored in 40 days Analysis.

7.3 Sample Preparation

7.3.1 Sample Extraction

Put the filter and glass sample tube into a Soxhlet extractor (6.4), add 250 µl of alternative liquid (5.13) to XAD-2 resin, Add 500 ml diethyl ether - n-hexane mixed solution (5.7), reflux extraction 16 h or more, hourly reflux not less than 3 times to 4 times. Extracted Completed, cooled to room temperature, remove the bottom bottle, rinsed the extraction cup interface, the cleaning fluid will be transferred to the end of the bottle. Add a little anhydrous sodium sulfate (5.6) to the sodium sulfate particles can be free-flowing, placed 30 min, dehydrated and dried.

Note. As long as the quality control requirements of this standard can be met, other sample extraction methods may also be used.

7.3.2 Sample concentration

The sample extract was transferred to a concentration flask, concentrated at below 45 °C, the solvent was completely converted to n-hexane, concentrated to about 1 ml until Purification.

7.3.3 Sample Purification

7.3.3.1 Magnesium silicate column

The bottom of the glass column (6.5) is filled with glass wool (5.24), 2 cm of anhydrous sodium sulfate (5.6) and n-hexane (5.2) the agent was wet-filled with 10 g of magnesium silicate (5.18), the bubbles were bubbled off, and 1 cm to 2 cm of anhydrous sodium sulfate (5.6) was added to the top. Use 40 ml of n-hexane Alkane (5.2) pre-rinsed the column and controlled the flow rate to about 2 ml/min to keep the liquid level slightly higher than the packed bed and transfer the concentrated liquid (7.3.2) to the column, the vial was washed twice with 1 ml of n-hexane and transferred to the column. Rinse the column with 40 ml of n-hexane and discard the flow Liquid. The column was eluted with.200 ml diethyl ether-n-hexane mixed solution (5.8) at an elution rate of 2 ml/min to 5 ml/min to receive the eluate.

The eluent was concentrated to about 1 ml by 7.3.2, 2 ml of acetonitrile was added, and the mixture was concentrated to continue the conversion. Finally, the solvent was converted to acetonitrile, Make up to 1.0 ml and transfer to vial for analysis.

7.3.3.2 Magnesium silicate solid phase extraction column

Take the solid phase extraction column (5.19), pre-rinse the solid phase with 10 ml of acetone-n-hexane mixed solution (5.9) and 10 ml of n-hexane Extract the column and discard the effluent. Keep the liquid level just above the bed and transfer the extract concentrate (7.3.2) to the column and wash with 1 ml n-hexane (5.2) the vial was washed twice and transferred to the column, followed by 5 ml n-hexane (5.2), 10 ml dichloromethane-n-hexane mixed solution (5.10) Rinse the SPE cartridges and discard the effluent. Elute with 10 ml of acetone-n-hexane mixed solution (5.9) and receive the eluate.

The eluent was concentrated to about 1 ml by 7.3.2, 2 ml of acetonitrile was added, and the mixture was concentrated to continue the concentration. Finally, the solvent was converted to acetonitrile, Make up to 1.0 ml and transfer to vial for analysis.

Note. As long as the quality control requirements of this standard can be met, other sample purification methods, solid phase columns of different specifications and different batch numbers of magnesium silicate may be used for elution the amount of solvent may be different, the need to conduct the conditions before use experiments.

7.4 Preparation of blank samples

7.4.1 Site blank

Site blank (7.1) Prepare a site blank sample following the same procedure as for sample preparation (7.3).

67.4.2 Laboratory blank

The same batch of glass sampling cartridges and filters according to the same sample preparation steps (7.3) Preparation of laboratory blank samples.

8 Analysis steps

8.1 Instrument reference conditions Column oven temperature. 35 ° C; injection volume. 10 µl; UV detector wavelength. 235 nm and 225 nm.

Gradient elution program. Mobile phase A. Acetonitrile; Mobile phase B. Water.

Table 1 Gradient elution program

Time (min) Mobile phase flow rate (ml/min) A (%) B (%) 0 1.0 35 65 15 1.0 45 55 40 1.0 100 0 50 1.0 35 65 1-dimethyl phthalate; 2-diethyl phthalate; 3-diphenyl phthalate (alternative); 4-butyl phthalate Benzyl phthalate; diisobutyl 5-phthalate; dibutyl phthalate; di-2-ethylhexyl phthalate;

Di-n-octyl phthalate.

Figure 2 Phthalates standard chromatogram

8.2 standard curve drawing Pipette a standard amount of standard solution (5.17) and dilute with acetonitrile (5.5) to give concentrations of 2.0 µg/ml, 5.0 µg/ml, 10.0 µg/ml, 20.0 µg/ml, 40.0 µg/ml standard series of solutions. From low concentration to high concentration into the high performance liquid chromatography, according to instrument reference conditions (8.1) Analyze the chromatograms of the target compound at different concentrations and record the retention time, peak height or peak area.

The target compound mass concentration as abscissa, the corresponding peak height or peak area for the vertical axis, the standard curve.

Phthalates standard chromatogram shown in Figure 2.

78.3 Determination of the sample

The determination of the sample is performed according to the same instrument conditions as the standard curve, and the peak height or area of the target compound is recorded and retained between.

8.4 Blank test

The blank sample (7.4) was measured according to the same instrument conditions as the sample.

9 results calculated and expressed

9.1 Qualitative analysis According to the retention time, the absorbance ratio at different wavelengths qualitative, or the use of samples of UV spectrophotometry and standard solution compared to the qualitative UV spectra.

9.2 Quantitative analysis According to the peak height or peak area of the target compound, the external standard method was used for quantification, and the quantitative wavelength was 235 nm.

9.3 Results Calculation Calculate the mass concentration () of the target compound in ambient air according to equation (1).

Vx-=) (0 (1)

Where. - the mass concentration of the target compound in ambient air, µg/m3;

i - mass concentration of the target compound in the sample obtained from the standard curve, µg/ml;

0 - the mass concentration of the target compound in the laboratory blank, whichever is the blank mean, µg/ml;

V - sample volume concentrated volume, ml;

Vs - Sampling volume at standard conditions (101.325 kPa, 273 K), m3.

9.4 results indicated when the concentration of phthalates in ambient air is greater than or equal to 1.00 µg/m3, the result retains three significant figures; for less than 1.00 µg/m3, the result is retained to the third decimal place.

10 precision and accuracy

10.1 Precision

Six laboratories respectively added spiked samples of 4.0 µg, 20.0 µg and 36.0 µg to air (equivalent to 0.028 µg/m3 for air samples, 0.139 µg/m3 and 0.250 µg/m3). The relative standard deviations in the laboratory ranged from 1.5% to 14% and from 2.2% to 17% and 1.0% ~ 15% respectively. The relative standard deviations (RSDs) were 3.3% ~ 13%, 3.2% ~ 8.4% and 3.2% ~ 5.8% 0.003 µg/m3 to 0.006 µg/m3, 0.016 µg/m3 to 0.033 µg/m3 and 0.022 µg/m3 to 0.042 µg/m3 respectively; the reproducibility limits were 0.004 µg/m3 to 0.011 µg/m3, 0.019 µg/m3 to 0.043 µg/m3, and 0.033 µg/m3 to 0.047 µg/m3. See Appendix B for details.

10.2 Accuracy

86 laboratories to extract the actual sample concentrate as a unified sample spiked recovery (n = 6), the standard addition of 10.0 µg (phase when the air sample was 0.069 µg/m3), the spiked recoveries ranged from 68.0% to 117%. The final spike recoveries were 80.3% ± 15.0% 96.6% ± 18.2%. See Appendix B for details.

11 Quality Assurance and Quality Control 11.1 blank no more than 20 samples per batch, with at least 2 on-site blank and 2 laboratory blank, blank phthalates content not exceeding Over the lower limit of measurement, the relative double deviation of parallel does not exceed 30%. Otherwise, repeat sample collection.

11.2 Calibration

11.2.1 Initial calibration the correlation coefficient of the standard curve >=0.995, otherwise, draw the standard curve again.

11.2.2 Continuous calibration at least one standard solution of the midpoint concentration of the curve is measured daily during the measurement of the sample, and the relative value of the measured value of the target compound and the standard value the error should be within ± 20%.

11.3 Recovery of substitutes After extraction, purification, concentration, analysis process, the recovery rate control range of 60% to 130%.

11.4 Sampling Efficiency in accordance with the requirements of HJ 691 Sampling efficiency determination, in addition to dimethyl phthalate, the sampling efficiency of the dynamic retention efficiency of general control System in the 50% to 150%.

11.5 parallel samples Two samples were collected in parallel. The relative deviation should not exceed 30% when the measurement result is greater than the lower limit of determination.

12 Waste treatment

The wastes generated by the laboratory shall be stored in categories and centrally stored, entrusted to qualified units for disposal.

13 Precautions

The experimental process should avoid the use of plastic materials and other interference-prone laboratory materials and utensils; glassware soaked in chromic acid washings Less than 6 h, and then rinsed with water, acetone and n-hexane; glassware placed for a long time before use must be washed with organic solvents surface;

Anhydrous sodium sulfate and the filter to be used after baking at high temperatures; before sampling, XAD-2 resin and PUF extraction and purification in accordance with the provisions, if not Guaranteed to be stored in a clean environment, to avoid prolonged storage in the laboratory.

Appendix A

(Normative)

Method detection limit and determination of the lower limit when the ambient air collected 144 m3 (standard state), the use of Soxhlet extraction or automatic Soxhlet extraction and magnesium silicate solid phase extraction column purification, Concentration volume of 1.0 ml, the method detection limit and lower limit in Table A.1.

Table A.1 method detection limit and lower limit of determination

Serial number of the compound name Method detection limit (Mg/m3) Method for determining the lower limit (Mg/m3) 1 dimethyl phthalate 0.003 0.012 2 diethyl phthalate 0.006 0.024

3 Butyl Benzyl Phthalate 0.002 0.008 4 diisobutyl phthalate 0.003 0.012 5 dibutyl phthalate 0.006 0.024 Bis (2-ethylhexyl) phthalate 0.006 0.024

7 Di-n-octyl phthalate 0.003 0.012 Appendix B (Informative) the precision and accuracy of the method Soxhlet extraction or automatic Soxhlet extraction and magnesium silicate solid phase extraction column purification, determination of three different concentrations of precision spiked samples Degree; the actual sample extract concentrate as a unified sample, measured spike recovery rate accuracy. Method precision shown in Table B.1, the method is accurate See table B.2 for degree.

Table B.1 Method Precision Summary Table (n = 6)

Serial number of the compound name Add amount (Mg) Measure the mean (Mg) Equivalent to air Sample concentration (Mg/m3) Laboratory phase the standard deviation (%) Laboratory phase the standard deviation (%) Repeatability limit r/(µg/m3) Reproducibility limit R/(µg/m3) 1 dimethyl phthalate 4.0 3.2 0.022 2.4 ~ 14 8.3 0.006 0.008 20.0 16.4 0.114 4.6 ~ 17 8.4 0.033 0.040 36.0 28.7 0.199 3.8 ~ 14 5.8 0.037 0.047 2 diethyl phthalate 4.0 3.4 0.024 3.9 ~ 11 13 0.005 0.010 20.0 16.8 0.117 3.0 ~ 14 7.6 0.026 0.034 36.0 29.3 0.203 3.1 ~ 13 4.6 0.030 0.038 3 butyl benzyl phthalate 4.0 4.0 0.028 3.4 ~ 8.7 7.4 0.004 0.007 20.0 20.7 0.144 5.0 ~ 11 7.9 0.032 0.043 36.0 34.8 0.242 2.7 ~ 15 3.4 0.042 0.045 4 diisobutyl phthalate 4.0 3.8 0.026 1.5 ~ 13 6.5 0.003 0.006 20.0 19.2 0.133 2.7 ~ 5.4 3.2 0.016 0.019 36.0 31.5 0.219 2.1 ~ 5.5 5.8 0.022 0.041 5 dibutyl phthalate 4.0 4.3 0.030 4.1 ~ 8.4 12 0.006 0.011 20.0 19.6 0.136 2.8 ~ 13 6.1 0.024 0.032 36.0 33.0 0.229 1.0 ~ 8.7 4.7 0.027 0.039 Di (2-ethyl phthalate) Hexyl) est...