HJ 1210-2021Soil and sediment - Determination of 13 aniline compounds and 2 benzidine compounds - Liquid chromatography-triple quadrupole mass spectrometry (English PDF)

7.1 Sample Collection and Storage

Soil samples were collected according to relevant requirements of HJ/T 166, water sediment samples were collected according to relevant requirements of HJ 494, and marine sediment samples were collected according to relevant requirements of HJ 494.

The samples were collected in accordance with the relevant requirements of GB 17378.3.Samples should be stored in clean sample vials (6.1) after collection and should be avoided during transportation.

Light, sealed, refrigerated, and shipped back to the laboratory for analysis as soon as possible. If the analysis cannot be done temporarily, 4-chloroaniline, 4-nitroaniline and 3-nitroaniline can be selected Keep refrigerated below 4 °C or cryopreserved below -18 °C, other target compounds should be stored frozen below -18 °C, see Table 1 for details. cryopreservation in order to avoid breaking the glass bottle during storage, transfer the sample to an aluminum foil ziplock bag (6.11) for airtight storage.

7.2 Preparation of samples

Use a freeze dryer (6.9) to dehydrate and dry the samples, grind and sieve the freeze-dried samples, and homogenize them to a size of about 0.25 mm.

particle. Prepared samples are stored in pre-cleaned sample vials (6.1) and analyzed as soon as possible according to the sample storage time.

7.3 Determination of moisture

The dry matter content of soil samples was determined according to HJ 613, and the moisture content of sediment samples was determined according to GB 17378.5.

7.4 Preparation of test specimens

7.4.1 Extraction

Weigh 5 g (accurate to 0.01 g) of the sample (7.2) into a stoppered centrifuge tube (6.10), add 1 g of sodium thiosulfate pentahydrate (5.6), Add 50.0 µl of the internal standard intermediate solution (5.14) and 10.0 ml of n-hexane-acetone mixed solvent (5.8) in turn, seal it with a vortex mixer (6.8) Mix well. After ultrasonic extraction for 30 min (place an ice box in the water tank to ensure that the temperature of the water bath is always lower than 25 °C), refrigerated centrifugation at 6000 r/min After 10 min, the supernatant was filtered through a hydrophilic polytetrafluoroethylene needle filter (5.20), and the filtrate was to be purified.

Note. If the pH value of the sample is not between 7 and 10, use formic acid (5.5) or ammonia water (5.7) to adjust the pH value to 7 to 10, and then perform extraction.

7.4.2 Purification

Fix the C18 solid phase extraction cartridge (5.19) on the solid phase extraction device (6.7). Rinse the cartridge with 5 ml of dichloromethane (5.1), Then use 5 ml methanol (5.4) to equilibrate the extraction column, close the flow control valve after the extraction column is full, soak for 5 minutes, slowly open the control valve, Discard the effluent. Before the solvent is drained, transfer 2.00 ml of the filtered sample extract (7.4.1) to the column and discard the effluent. exist Before the solvent is drained, close the control valve, add 5 ml of methanol (5.4), slowly open the control valve after 5 min, and receive the eluent until it flows out completely.

7.4.3 Concentration

At room temperature, turn on nitrogen until there are slight fluctuations on the surface of the solvent (avoid vortex formation). Concentrate the purified eluent (7.4.2) with nitrogen blowing at least 0.8 ml, dilute to 1.0 ml with methanol (5.4), and transfer to a 2 ml brown sample bottle. Refrigerate below 4 °C, and complete the analysis within 7 days.

Or freeze below -18 °C, and complete the analysis within 28 days.

7.4.4 Preparation of test solutions

Accurately pipette 250 µl of the concentrated purified eluent (7.4.3), make up to 1.0 ml with water, mix well, use a syringe filter (5.20) After filtration, it was transferred to a 2 ml brown sample bottle for analysis on the machine.

Note. If the concentration of the target compound in the sample exceeds the highest point of the standard curve, reduce the sampling amount and prepare the sample again.

7.5 Preparation of blank samples

Using quartz sand (5.18) in place of the actual sample, prepare a blank sample in the same manner as in the preparation of the sample (7.4).

8.1 Instrument Reference Conditions

8.1.1 Liquid chromatography reference conditions

Mobile phase A. formic acid-methanol solution (5.9), mobile phase B. formic acid aqueous solution (5.10), gradient elution procedure is shown in Table 2; flow rate.

8.1.2 Reference conditions for mass spectrometry

Ion source. Electrospray ion source (ESI), positive ion mode.

Monitoring method. multiple reaction monitoring (MRM).

See Appendix C for the remaining conditions.

8.1.3 Instrument tuning

There are certain differences in the tuning parameters of instruments from different manufacturers.

Calibration of instrument mass and resolution to ensure that the instrument is in the best test state.

8.2 Calibration

8.2.1 Establishment of standard curve

Dilute the standard solution (5.17) for aniline and benzidine compounds with internal standard solution II (5.16), and prepare at least 6 concentrations of standard solution.

quasi-series (see Table 3 for reference mass concentration), stored in a brown sample bottle for testing.

According to the reference conditions of the instrument (8.1), analyze the standard series of solutions from low concentration to high concentration in turn.

The mass concentration of the target compound is the abscissa, the ratio of the peak area (or peak height) of the target compound to the peak area (or peak height) of the corresponding internal standard the product with the concentration of the internal standard is the ordinate, and a standard curve is established.

8 µg/kg, 31 µg/kg~65 µg/kg and 38 µg/kg~109 µg/kg; reproducibility limits are 10 µg/kg~28 µg/kg, 104 µg/kg~ 314 µg/kg and 153 µg/kg to 446 µg/kg.

Six laboratories performed six replicates of a uniform sample of loam and marine sediment spiked at 20 µg/kg (as aniline) Determination (quantification using 4 internal standards). the relative standard deviations within the laboratory are 1.0% to 15% and 0.80% to 14%, respectively;

The standard deviations were 5.8% to 19% and 6.1% to 19%, respectively; the repeatability limits were 2 µg/kg to 10 µg/kg and 3 µg/kg to 9 µg/kg, respectively;

The limit of detection is 8 µg/kg~31 µg/kg and 9 µg/kg~28 µg/kg, respectively.

The 6 laboratories respectively tested the river sediment samples with a spiked concentration of.200 µg/kg (calculated as aniline) and a spiked concentration of 360 µg/kg (calculated as aniline).

6 repeated determinations (using 4 internal standards for quantification) of sand samples with aniline meter). the relative standard deviation in the laboratory is 0.80%~ 15% and 1.2%-11%; the relative standard deviations between laboratories are 6.7%-20% and 7.6%-18%, respectively; the repeatability limits are 26 µg/kg~ 74 µg/kg and 46 µg/kg to 128 µg/kg; reproducibility limits were 93 µg/kg to 269 µg/kg and 170 µg/kg to 500 µg/kg, respectively.

For precision data see Table D.1 in Appendix D.

10.2 Correctness

6 laboratories measured the quartz sand samples spiked with concentration of 20 µg/kg,.200 µg/kg, 360 µg/kg (calculated as aniline) respectively (4 kinds of internal standards were used for quantification). The recovery rates of standard additions ranged from 72.0% to 127%, 73.0% to 128%, and 71.4% to 123%, respectively;

The final yields were 86.7%±15.5%~109%±24.6%, 89.6%±23.0%~109%±15.2% and 87.2%±20.6%~ 110%±13.7%.

Six laboratories measured uniform samples of loam and marine sediments spiked at a concentration of 20 µg/kg (as aniline) (using 4 kinds of internal standard quantification). the recovery rates of the standard additions ranged from 72.5% to 124% and 69.2% to 119%, respectively; the final values of the standard addition recoveries were 85.1%, respectively.

±18.3%~106%±23.8% and 83.8%±14.5%~104%±18.5%.

The 6 laboratories respectively tested the river sediment samples with a spiked concentration of.200 µg/kg (calculated as aniline) and a spiked concentration of 360 µg/kg (calculated as aniline).

aniline meter) for the determination of sand samples (quantified by using 4 internal standards). the recovery rates of the standard additions ranged from 70.2% to 122% and 72.4% to 72.4%.

The final recovery rate of standard addition was 88.6%±25.5%~104%±31.7% and 87.2%±22.5%~108%±19.4%, respectively.

For accuracy data see Table D.2 in Appendix D.

11.1 Blank test

At least one laboratory blank should be determined for every 20 samples or batches (less than 20 samples), and the results should be below the method detection limit.

11.2 Calibration

A standard curve should be established for each batch of samples, and the correlation coefficient should be greater than or equal to 0.995, otherwise the standard curve should be redrawn.

Every 20 samples or each batch (less than 20 samples) should be determined at an intermediate concentration point of the standard curve, and the determination result should be consistent with the standard value.

The error is within ±20%, otherwise the standard curve should be redrawn.

11.3 Parallel samples

At least one parallel sample is determined for every 20 samples or each batch (less than 20 samples), and the relative deviation of the parallel samples should be within ±35%.

11.4 Blank Marking

Every 20 samples or every batch (less than 20 samples) at least one blank spiked sample is determined, and the spiked recovery rate should be 65% to 130% between.

11.5 Matrix spikes

For every 20 samples or batches (less than 20 samples) at least one matrix spiked sample is determined, the spiked recovery of soil samples should be within Between 65% and 130%, the spiked recovery of sediment samples should be between 60% and 140%.