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7.
(1) Qualitative target compound
Qualitatively based on the retention time of each component of the standard substance and the comparison of the standard mass spectrum
(2) Quantitative calculation
1.
According to the calibration curve formula (1), the mass concentration p, ng calculation formula (2) of each compound can be obtained
Where y i ——response value of target quantitative ion;
y IS ——Response value of internal standard compound quantitative ion;
p i ——the mass concentration of the target substance, ng/mL;
p IS ——the mass concentration of the internal standard compound, ng/mL;
a——The slope of the calibration curve;
b——The intercept of the calibration curve
2.
In the formula, w——(content of target compound, ug/kg;
P i ——the absolute mass of the target compound calculated from the calibration curve, ng;
m——weigh the mass of the sample, g;
wH 2 moisture content o-- sample,%
8.
(1) Blank analysis
At least one laboratory blank should be made for each batch of samples (no more than 20 samples), and the mass concentration of the target compound in the blank should be lower than the detection limit of the method, otherwise the cause should be found, and the laboratory blank test can be carried out only after passing the test.
(2) Curve calibration
A calibration curve should be drawn for each batch of samples
(3) Parallel sample determination
Analyze one parallel sample for every 10 samples or each batch (less than 20 samples/batch), and the relative deviation of the measurement result of a single parallel sample is generally not more than 30%
(4) Determination of the matrix spiked samples
Each batch of samples (up to 20 samples) should analyze 1 pair of matrix spiked samples
Nine, matters needing attention
(1) The solvents and reagents used in the test have a certain degree of toxicity, so the pretreatment process of the sample should be carried out in a fume hood, and the operator should do his own protection work
(2) The final mass concentration of the sample is calculated based on the mass of soil dry matter
(3) Instruments, equipment and utensils containing plastic materials cannot be used during the experiment
(4) Generally speaking, samples with a moisture content of not higher than 20% can be dried with anhydrous sodium sulfate.
Related Links: Determination of Soil Phthalate Esters by Gas Chromatography/Mass Spectrometry (2)