HJ 1051-2019Soil - Determination of petroleum oil - Infrared spectrophotometry (English PDF)

3.1 Petroleum

It means that under the conditions specified in this standard, it can be extracted by tetrachloroethylene and not adsorbed by magnesium silicate. The wave number is 2930.

-1, 2960 cm-1, 3030 cm-1 Substances with characteristic absorption at all or part of the band.

7.1 Sample collection and storage

Collect and store samples in accordance with the relevant requirements of HJ/T 166. The sample is filled with the filled sampling bottle (6.7) and sealed Store in the refrigerator and return to the laboratory for analysis as soon as possible. If it is not analyzed temporarily, it should be stored refrigerated below 4 °C for a storage time of 7 d.

7.2 Sample preparation

Remove foreign materials (stones, leaves, etc.) from the sample and mix well. Weigh a 10 g (accurate to 0.01 g) sample and add Measure the amount of anhydrous sodium sulfate (5.5), grind and homogenize into a quicksand shape, and transfer to a stoppered conical flask (6.5).

7.3 Determination of dry matter content

While weighing the sample, take another sample and determine the dry matter content of the soil sample according to HJ 613.

7.4 Preparation of test specimens

Add 20.0 ml of tetrachloroethylene (5.1) to the Erlenmeyer flask (7.2), seal, place in a shaker (6.2), and add.200 Extraction frequency of 30 times per minute. After standing for 10 minutes, use a glass funnel (6.6) with a glass fiber filter (5.8) Filter the extract into a 50 ml cuvette. Repeat the extraction with 20.0 ml of tetrachloroethylene (5.1).

All samples were transferred and filtered. Wash the conical flask, filter, glass funnel, and soil with 10.0 ml of tetrachloroethylene (5.1) Samples and combined extracts. Pour the extract into the adsorption column (5.18), discard the first 5 ml of the effluent, and retain the remaining effluent.

To be tested.

Note. If the oil content in the soil sample is too high, the number of repeated extractions can be appropriately increased.

7.5 Preparation of blank sample

Weigh 10 g (accurate to 0.01 g) quartz sand (5.7) in place of the soil sample, as per the sample preparation (7.4) the procedure is to prepare a blank sample.

8.1 Calibration

Pipette 2.00 ml of standard use solution of n-hexadecane (5.10), 2.00 ml of standard use solution of isooctane (5.12), and 10.00 ml of benzene standard use solution (5.14) in three 100 ml volumetric flasks, make up to the mark with tetrachloroethylene (5.1), Shake well. The concentrations of n-hexadecane, isooctane and benzene standard solutions were 20.0 mg/L, 20.0 mg/L and 100 mg/L, respectively.

Using a 40 mm quartz cuvette with tetrachloroethylene (5.1) as a reference, measure n-hexadecane, isooctane and benzene standards the absorbances of the quasi-solutions at 2930 cm-1, 2960 cm-1, and 3030 cm-1 were A 2930, A 2960, and A3030. N-hexadecane, the absorbances of the isooctane and benzene standard solutions at the above-mentioned wavenumbers are simultaneous equations according to formula (1).

Corresponding correction coefficients X, Y, Z and F.

AZAYAX 29303030296029301 (1) where. rho1-concentration of petroleum standard solution, mg/L;

A2930, A 2960, A3030--absorbance measured at each corresponding wave number;

X--the coefficient corresponding to the absorbance of the CH bond in the CH2 group, mg/L/absorbance;

Y--the coefficient corresponding to the absorbance of the CH bond in the CH3 group, mg/L/absorbance;

Z--coefficient corresponding to the absorbance of the CH bond in the aromatic ring, mg/L/absorbance;

F--The correction factor for the effect of aliphatic hydrocarbons on aromatic hydrocarbons, that is, the absorption of n-hexadecane at 2930 cm-1 and 3030 cm-1 Photometric ratio.

For n-hexadecane and isooctane, due to their zero aromatic content, 029303030 =-A, then.

) () () (29602930 HAYHAXH ..= (3) ) () () (29602930 IAYIAXI ..= (4) the F value can be obtained from formula (2), and the X and Y values can be obtained from formulas (3) and (4). For benzene.

BAZBAYBAXB

) () () () (2930303029602930 (5) the Z value can be obtained from formula (5).

Where. rho (H)-the concentration of n-hexadecane standard solution, mg/L;

rho (I)-concentration of isooctane standard solution, mg/L;

rho (B)-the concentration of benzene standard solution, mg/L;

A2930 (H), A2960 (H), A3030 (H)-Measure the absorbance of n-hexadecane standard solution at each corresponding wave number A2930 (I), A2960 (I), A3030 (I)-the absorbance of the isooctane standard solution measured at each corresponding wavenumber;

A2930 (B), A2960 (B), A3030 (B)-Measure the absorbance of benzene standard solution at each corresponding wavenumber Note. If the calibration coefficient is set when the infrared oil meter or infrared spectrophotometer is shipped from the factory, you can directly check the calibration coefficient according to 11.3.1.

Check.

8.2 Determination of sample

Transfer the remaining effluent after adsorption with magnesium silicate (7.4) to a 40 mm quartz cuvette and use tetrachloroethylene (5.1) for reference, the absorbances A 2930, A2960, and A3030 were measured at the wave numbers of 2930 cm-1, 2960 cm-1, and 3030 cm-1. according to Equation (1) calculates the petroleum concentration.

8.3 Blank test

Follow the same procedure as for the measurement of the sample (8.2), and perform the measurement of the blank sample (7.5).

9.1 Calculation of results

The content of petroleum in the soil w (mg/kg) is calculated according to formula (6).

dmWm

Where. w- petroleum content in soil, mg/kg;

rho2--Petroleum concentration in the extract, mg/L;

V--extract volume, ml;

m--mass of soil sample, g;

Wdm--dry matter content of soil,%.

9.2 Representation of results

The number of digits after the decimal point in the measurement result is the same as the detection limit of the method. A maximum of 3 significant digits are retained.

10.1 Precision

Six laboratories have uniformly collected garden soil samples with a petroleum concentration of about 30 mg/kg and 70 mg/kg sewage irrigation areas the soil uniform sample and the 150 mg/kg iron smelter soil uniform sample were subjected to 6 repeated determinations. The relative standard deviation in the laboratory the differences were 5.0% to 7.4%, 3.9% to 5.9%, and 1.9% to 4.0%; the relative standard deviations between laboratories were 3.9%, 2.7% and 2.4%; repeatability limits are 5 mg/kg, 9 mg/kg, and 11 mg/kg, respectively; reproducibility limits are 6 mg/kg, 10 mg/kg and 14 mg/kg.

10.2 Accuracy

Six laboratories have uniformly collected garden soil samples with a petroleum concentration of about 30 mg/kg and 70 mg/kg sewage irrigation areas A unified sample of soil and a uniform sample of 150 mg/kg of iron from the ironworks were used for analysis and determination. The spiked amounts were 300 µg, 700 µg and 1500 µg, with spiked recoveries ranging from 83.6% to 88.9%, 84.9% to 91.7%, and 84.4% to 90.3%;

The final recoveries were (86.5 ± 4.2)%, (88.0 ± 5.0)%, and (87.1 ± 4.8)%.

11.1 Tetrachloroethylene quality inspection

Tetrachloroethylene shall be stored protected from light. Before use, the quality inspection and judgment of tetrachloroethylene must be carried out in accordance with (5.1) to confirm compliance.

Can only be used after required.

11.2 Blank test

Do at least two laboratory blank tests for every 20 samples or batches (<=20 samples/batch). The blank test results should be Below method detection limit.

11.3 Calibration coefficient test

Each batch of samples should be tested for the correction coefficient. When using, according to the required concentration, take an appropriate amount of petroleum standard use solution.

(5.16), using tetrachloroethylene as a solvent to prepare a petroleum standard solution of appropriate concentration, the same step as the sample measurement (8.2) Carry out the measurement immediately, and calculate the concentration of petroleum standard solution according to formula (1). If the relative error between the measured value and the standard value Within ± 10%, the correction factor can be used, otherwise the correction factor is re-measured and checked until it meets the conditions.

Testing can also be performed using certified reference materials/samples.

11.4 Parallel samples

Every 20 samples or each batch (<=20 samples/batch) samples should be measured in a parallel sample, the relative deviation of parallel samples should be <=30%.

11.5 Matrix Spiking

Every 20 samples or each batch (<=20 samples/batch) samples should be measured for a matrix spiked sample, and the spiked recovery rate should be Controlled between 70% and 110%.