Solid waste. Determination of volatile halogenated hydrocarbons. 35 VOCs purge and trap/gas chromatography-mass spectrometry (1)

1.

This method is suitable for the determination of the content of volatile organic compounds in solid waste and solid waste leachate.

Second, the principle of the method

The volatile halogenated hydrocarbons in the sample are purged out with inert gas such as high-purity nitrogen and adsorbed in the trap tube.

3.

(1) Methanol : pesticide residue level

(2) Quartz sand: 40-100 mesh, burned in a muffle furnace at 400°C for 4 hours, placed in a desiccator to cool to room temperature, and transferred to a ground glass bottle for storage

(3) Extractant: ultrapure water; no VOCs interference, can be purchased or prepared in the laboratory

(4) Magnetic stirrer: wash with methanol and use after soaking in ultrapure water

(5) Mixed standard solution of volatile organic compounds: p=1000ug/mL, and the solvent is methanol

(6) Internal standard: fluorobenzene, 1,4-dichlorobenzene-d4, chlorobenzene -d _.

(7) Substitute: Toluene-d ₈ and p-bromofluorobenzene are mixed into a standard solution, p=1000ug/mL, the solvent is methanol , and other substances with similar properties can also be used

(8) for bromofluorobenzene : p = 10ug / mL, the solvent is methanol

Four, instruments and equipment

(1) Solution delivery pump

(2) Zero headspace device (with 0.

(3) Flip the oscillator

(4) Purge and trap instrument (with soil sample injection function)

(5) EI source single quadrupole gas-mass spectrometer
.

Five, pre-treatment

(1) Solid waste leachate

1.
Preparation of leaching solution

"Determination of 37 Volatile Organic Compounds/35 Volatile Halogenated Hydrocarbons in Solid Waste Headspace/Gas Chromatography-Mass Spectrometry (1)"

2.
Preparation for purge and trap analysis

Take 5mL of the extract in the purge and trap bottle of Yujing, add a certain amount of internal standard and substitute solution (the on-board mass concentration is recommended to be consistent with the mass concentration of substitute and internal standard in the standard series), and put it in the purge The trap is used for sampling and then connected to the GC-M3 for analysis
.

(2) Solid waste samples

1.
Low-content solid waste samples (samples with predicted content lower than 1000ug/kg)

Take out the frozen samples in the laboratory.
After returning to room temperature, put a magnetic stirrer into the purge and trap bottle, weigh 5g of the sample and place it in the bottle, quickly add 5.
0mL ultrapure water to the bottle and add A certain amount of internal standard and substitute solution (the recommended mass concentration on the machine is the same as the mass concentration of the substitute and internal standard in the standard series), immediately seal, oscillate on a shaker at a frequency of 150 times/min for 10 minutes, and wait to be purged Capture-CC/MS detection
.

2.
High-content solid waste samples (samples with predicted content higher than 1000ug/kg)

Weigh 5g of the sample and place it in a purge trap bottle, quickly add 10 mL of methanol, seal it, and vibrate on a shaker at a frequency of 150 times/min for 10 minutes
.
After standing and settling, pipette about 1 mL of the extract into a brown glass bottle and seal it.
If the extract cannot be analyzed in time, it should be stored at 4°C
.
Add 5g of quartz sand, 5mL of ultrapure water and 10-100uL of methanol extraction solution to a clean purge and trap bottle (to room temperature)
.
Add a certain amount of internal standard and substitute solution (the on-machine mass concentration is recommended to be consistent with the mass concentration of substitute and internal standard in the standard series), immediately seal, and oscillate on a shaker at a frequency of 150 times/min for 10 minutes, and wait for blowing Sweep and trap/GC-MS detection
.