Determination of Phthalic Acid Esters in Soil by Gas Chromatography/Mass Spectrometry (1)

1.

This method is suitable for the determination of 11 phthalate esters in soil

Second, the principle of the method

The phthalates in the soil are extracted by organic solvents, and the extracts are separated by gas chromatography, measured by mass spectrometer, qualitatively by characteristic ions, and quantified by internal standard method

3.

Unless otherwise stated, the analysis is performed with superior grade pure chemical reagents that meet the national standards, and the experimental water is newly prepared ultrapure water

(1) Ethyl acetate : pesticide residue level

(2) Anhydrous sodium sulfate : pure class superior

(3) Phthalate standard solution: p=1000ug/mL, the solvent is ethyl acetate

(4) Internal standard: DEP-d4, DBP-d4, DEHP-d4, p=100ug/mL, and the solvent is methanol

(5) Solid phase glass cartridge: neutral alumina , 1g/6mL

Four, instruments and equipment

(1) EI source single quadrupole gas chromatography mass spectrometer

(2) Chromatographic column: HP-5MSUI, 30.

(3) Old rotary oscillator: 0～280 times/min

(4) Erlenmeyer flask: 250mL

(5) Balance: the accuracy is 0.

(6) Oven

Five, pre-treatment

(1) Sample preparation

" Determination of Organochlorine Pesticides in Soils and Sediments by Gas Chromatography (1) "

(2) Sample extraction

Weigh 10g fresh/lyophilized sample (adjust appropriately to predict the mass concentration range of the target substance), add an appropriate amount of anhydrous sodium sulfate , mix the sample well, transfer all to a 250mL conical flask, add internal standard (the mass concentration of the machine It is recommended to be consistent with the internal standard mass concentration in the standard series), add 20 mL of ethyl acetate , and shake in parallel on a shaker for 30 minutes
.
After shaking, filter the extract with filter paper.
If the sample solution is clean, no purification is required.
Pipette 1 mL of the extract for CC-MS analysis and determination
.

(3) Purification

If the color of the extracted liquid is darker after filtration, it needs to be purified by a glass-made neutral alumina solid phase extraction cartridge before it can be analyzed on the machine
.
Purification steps: Rinse the solid phase extraction cartridge with 10 mL of ethyl acetate, and discard the effluent
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Dry the solid phase extraction cartridge with nitrogen for 1 min
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Transfer the extract to the small column and collect the filtrate
.
If the extraction liquid flow rate is slow, appropriate vacuum filtration can be carried out to speed up the filtrate flow out
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The filtrate is concentrated to 1mL and is ready to be tested on the machine
.

(4) Determination of dry matter content

" Determination of Organochlorine Pesticides in Soils and Sediments by Gas Chromatography (1) "

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