HJ 637-2018 English PDF (HJ637-2018)

This standard specifies the infrared spectrophotometric method for the determination of petroleum, animal fats and vegetable oils in water. This standard applies to the determination of petroleum, animal fats and vegetable oils in industrial and domestic sewage. When the volume of sample is 500 ml, the volume of the extract is 50 ml, the 4 cm quartz cuvette is used, the detection limit of method is 0.06 mg/L, the lower limit of determination is 0.24 mg/L.

HJ 637-2018
HJ
ENVIRONMENTAL PROTECTION STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
Replacing HJ 637-2012
Water quality - Determination of petroleum, animal fats
and vegetable oils - Infrared spectrophotometry
ISSUED ON. OCTOBER 10, 2018
IMPLEMENTED ON. JANUARY 01, 2019
Issued by. Ministry of Ecological Environment
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Principle of method ... 6
5 Reagents and materials ... 6
6 Instruments and equipment... 8
7 Samples ... 9
8 Analytical procedures ... 10
9 Calculation and representation of results ... 12
10 Precision and accuracy ... 14
11 Quality assurance and quality control... 14
12 Waste disposal ... 15
13 Precautions ... 15
Water quality - Determination of petroleum, animal fats
and vegetable oils - Infrared spectrophotometry
Warning. The tetrachloroethylene used in the experiment is harmful to
human health. The preparation of standard solution, the preparation of
sample, the determination process shall be carried out in a fume hood.
During operation, it shall wear protective equipment as required to avoid contact with skin and clothing.
1 Scope
This standard specifies the infrared spectrophotometric method for the
determination of petroleum, animal fats and vegetable oils in water.
This standard applies to the determination of petroleum, animal fats and vegetable oils in industrial and domestic sewage.
When the volume of sample is 500 ml, the volume of the extract is 50 ml, the 4 cm quartz cuvette is used, the detection limit of method is 0.06 mg/L, the lower limit of determination is 0.24 mg/L.
2 Normative references
The contents of this standard refer to the following documents or their terms. For undated references, the valid version applies to this standard.
HJ/T 91 Technical specifications requirements for monitoring of surface water and waste water
3 Terms and definitions
The following terms and definitions apply to this standard.
3.1
Oil and grease
It refers to, under the conditions of pH ≤ 2, the substances that can be extracted by tetrachloroethylene and have characteristic absorption at
wavenumbers of 2930 cm-1, 2960 cm-1, 3030 cm-1, mainly including
petroleum, animal fats and vegetable oils.
5.4 n-hexadecane (C16H34). Chromatographical pure.
5.5 Isooctane (C8H18). Chromatographical pure.
5.6 Benzene (C6H6). Chromatographical pure.
5.7 Anhydrous sodium sulfate (Na2SO4).
PLACE it in a muffle furnace to heat it at 550 °C for 4 h. After it is slightly cooled, CONTAIN it into a ground glass bottle. PLACE it in a desiccator for storage. 5.8 Magnesium silicate (MgSiO3). 150 μm ~ 250 μm (100 mesh ~ 60 mesh).
TAKE magnesium silicate and PLACE it in a porcelain evaporating dish. PLACE it in a muffle furnace at 550 °C to heat it for 4 h. After it is slightly cooled, TRANSFER it into a desiccator to cool it to room temperature. WEIGH an
appropriate amount of magnesium silicate in a ground glass bottle. According to the mass of magnesium silicate, ADD an appropriate amount of distilled water in a ratio of 6% (m/m). CAP it tightly and SHAKE it thoroughly. LET it be standing for 12 h before use. PRESERVE it in a glass bottle.
5.9 Glass wool
Before use, USE the tetrachloroethylene (5.3) to soak and rinse the glass wool. DRY it naturally to prepare for use.
5.10 Standard stock solution of n-hexadecane. ρ≈10000 mg/L.
WEIGH 1.0 g (accurate to 0.1 mg) of n-hexadecane (5.4) in a 100 ml volumetric flask. USE tetrachloroethylene (5.3) to make its volume reach to the mark. SHAKE it uniformly. STORE it at 0 °C ~ 4 °C, which can be preserved in the dark for 1 year.
5.11 Standard use solution of n-hexadecane. ρ = 1000 mg/L.
USE tetrachloroethylene (5.3) to dilute the standard stock solution of n- hexadecane (5.10) to the volume in a 100 ml volumetric flask.
5.12 Standard stock solution of isooctane. ρ≈10000 mg/L.
WEIGH 1.0 g (accurate to 0.1 mg) of isooctane (5.5) in a 100 ml volumetric flask. USE tetrachloroethylene (5.3) to make its volume reach to the mark. SHAKE it uniformly. STORE it at 0 °C ~ 4 °C, which can be preserved in the dark for 1 year.
5.13 Standard use solution of isooctane. ρ = 1000 mg/L.
USE tetrachloroethylene (5.3) to dilute the standard stock solution of isooctane (5.12) to the volume in a 100 ml volumetric flask.
6.6 Colorimetric tube. 25 ml, 50 ml, ground, with a stopper.
6.7 Separating funnel. 1000 ml with Teflon cock.
6.8 Measuring cylinder. 1000 ml.
6.9 Commonly used laboratory utensils and equipment.
7 Samples
7.1 Collection of sample
With reference to the relevant provisions of HJ/T 91, USE the sampling bottle (6.3) to collect about 500 ml of water sample. ADD hydrochloric acid solution (5.2) to acid it to pH ≤ 2.
7.2 Preservation of samples
If the sample cannot be determined within 24 h, it shall be stored at 0 °C ~ 4 °C and determined within 3 days.
7.3 Preparation of samples
7.3.1 Preparation of oil and grease samples
TRANSFER the sample into a 1000 ml separatory funnel (6.7). MEASURE 50
ml of tetrachloroethylene (5.3) to rinse the sample bottle. TRANSFER all the rinsing solution into the separatory funnel (6.7). SHAKE it completely for 2 min. Frequently OPEN the cock for exhaust. LET it be standing for stratification. USE tweezers to take glass wool (5.9) and place it in a glass funnel (6.4). TAKE an appropriate amount of anhydrous sodium sulfate (5.7) to pave above the glass wool. OPEN the cock of the separatory funnel. MAKE the lower layer of organic phase extract pass the glass funnel (6.4) which contains anhydrous sodium sulfate (5.7) into a 50 ml colorimetric tube (6.6). USE an appropriate amount of tetrachloroethylene (5.3) to wet and rinse the glass funnel (6.4). COLLECT the rinsing solution into the extract. USE tetrachloroethylene (5.3) to make its volume reach to the mark. TRANSFER all the upper layer of aqueous phase into the measuring cylinder. MEASURE the volume of sample. TAKE record. Note. It may use automatic extraction instead of manual extraction. It may use aluminum silicate filter cotton instead of glass wool. Before use, the aluminum silicate filter cotton shall be placed in a muffle furnace at 550 °C to heat it for 4 h, cooled before use.
7.3.2 Preparation of petroleum specimens
7.3.2.1 Oscillation adsorption method
solution which is measured under the corresponding wavenumber;
A2930(I), A2960(I), A3030(I) - The absorbance of the isooctane standard solution which is measured under the corresponding wavenumber;
A2930(B), A2960(B), A3030(B) - The absorbance of the benzene standard
solution which is measured under the corresponding wavenumber.
Note 1. It may use pristane instead of isooctane, use toluene instead of benzene to determine the correction factor by the use of the same method. Note 2. At the time of exit-factory of infrared spectrophotometer or infrared oil detector, if the correction factor is set, it can directly check the correction factor according to 11.3.1.
8.2 Determination
8.2.1 Determination of oil and grease
TRANSFER the extract (7.3.1) into a 4 cm quartz cuvette. USE the
tetrachloroethylene as a reference. MEASURE the absorbance A2930, A2960, A3030 at 2930 cm-1, 2960 cm-1, 3030 cm-1, respectively.
8.2.2 Determination of petroleum
TRANSFER the extract (7.3.2) which was adsorbed by magnesium silicate into a 4 cm quartz cuvette. USE the tetrachloroethylene as a reference. MEASURE the absorbance A2930, A2960, A3030 at 2930 cm-1, 2960 cm-1, 3030 cm-1,
respectively.
8.3 Determination of blank specimen
According to the procedures same as the determination of specimen (8.2), DETERMINE the blank specimen (7.4).
9 Calculation and representation of results
9.1 Calculation
9.1.1 Calculation of concentration of oil and grease or petroleum
The concentration of oil and grease or petroleum in the sample is calculated according to formula (6).
retaining up to 3 significant digits.
10 Precision and accuracy
10.1 Precision
Six laboratories perform six repeated determinations on petroleum samples which have a prepared concentration of 0.20 mg/L, 1.00 mg/L, 4.00 mg/L, respectively. The inner-laboratory relative standard deviations are 2.4% ~ 13%, 0.8% ~ 4.7%, 0.8% ~ 3.6%. The inter-laboratory relative standard deviations are. 20%, 9.7%, and 5.9%, respectively. The repeatability limit r is 0.05 mg/L, 0.08 mg/L, 0.26 mg/L, respectively. The reproducibility limit R is 0.13 mg/L, 0.26 mg/L, 0.65 mg/L, respectively.
Six laboratories perform six repeated determinations on two different types of actual samples which contain industrial waste water that has a concentration of 0.94 mg/L and 1.84 mg/L and domestic sewage. The inner-laboratory relative standard deviation is 1.1% ~ 4.7% and 1.0% ~ 5.2%, respectively. The inter- laboratory relative standard deviation is 6.2% and 9.1%, respectively. The repeatability limit r is 0.09 mg/L and 0.17 mg/L, respectively. The reproducibility limits R is 0.18 mg/L and 0.50 mg/L, respectively.
10.2 Accuracy
Six laboratories perform the spiked analytical determination for the blank samples, respectively, the spiked amount is 0.10 mg, 0.50 mg, 2.00 mg,
respectively. MAKE six repeated determinations. The spiked recovery rate ranges 75% ~ 138%, 78% ~ 104%, 81% ~ 95%, respectively. The final value of the spiked recovery rate is 111% ± 44%, 94% ± 18%, 91% ± 11%, respectively. Six laboratories determine the spiked recovery rate of two different types of actual water samples of industrial wastewater and domestic sewage,
respectively. The spiked amount is 0.50 mg and 1.00 mg, respectively. MAKE six repeated determinations. The spiked recovery rate ranges 84% ~ 98%, 81% ~ 100%, respectively. The final values of the spiked recovery rate are. 92% ± 11%, 91% ± 15%, respectively.
11 Quality assurance and quality control
11.1 Quality inspection of tetrachloroethylene
Tetrachloroethylene shall be stored in the dark. Before use, it shall follow (5.3) to inspect and determine the quality of tetrachloroethylene, to confirm that is complies with requirements before use.