Soil and sediments. Determination of 36 volatile organic compounds and 35 volatile halogenated hydrocarbons. Headspace gas chromatography-mass spectrometry (2)

Six, analysis and testing

(1) Instrument conditions (for reference only, can be adjusted appropriately according to the actual instrument)

1.

Furnace valve temperature: 140℃

Sample bottle standby flow rate: 20mL/min

Heating box temperature: 75℃

Quantitative loop temperature: 100℃

Transmission line temperature: 110℃

Sample bottle balance: 30min

Injection duration: 0.

GC cycle time: 42min

Sample bottle volume: 20mL

Vial shaking: Level 5, 71 times/min, acceleration at 260cm/s

Filling pressure: 15psi

2.

Injection port: temperature is 250℃, column flow rate is 1.

3.

Ion source: EI, ion source temperature 230°C, ionization energy 70eV, SIM scanning

According to the performance of the instrument and the relevant standard limit requirements, the data can also be collected in a full scan mode
.
The full scan parameter is 35-280amu .
The grouping situation can be adjusted according to the separation of each peak and the number of description points of each peak (generally more than 10)
.

Under the above conditions, use mass spectrometry to perform qualitative analysis and determine the retention time of each compound
.
See Table 8-1 for details .

Table 8-13 Retention time of 6 kinds of VOCs and qualitative and quantitative reference ions

(2) Calibration curve

Add 2g of pure quartz sand and 10mL matrix modifier to the headspace bottle, and then take an appropriate amount of standard solution in the above headspace bottle to prepare a standard series of more than 5 points that meets the detection limit of the instrument, the linear range and the actual sample mass concentration (Such as 5.
0ug/L, 10.
0ug/L, 20.
0ug/L, 50.
0ug/L, 80.
0ug/L), add appropriate amount of internal standards and substitutes (such as 40ug/L), configure into a standard series
.
Quantification by internal standard method
.
Refer to Table 8-1 and Table 8-2 for the retention time qualitative and quantitative ions under reference instrument conditions
.

Table 8-2 Retention time and qualitative and quantitative reference ions of 35 volatile halogenated hydrocarbons

Related Links: Determination of 36 Volatile Organic Compounds and 35 Volatile Halogenated Hydrocarbons in Soils and Sediments Headspace Gas Chromatography-Mass Spectrometry (1)