GBZ/T 300.96-2018Determination of toxic substances in workplace air -- Part 96: Sevoflurane, isoflurane and enflurane (English PDF)

4.1 Principle

The vaporous sevoflurane, isoflurane and enflurane in the air are collected by activated carbon tube, desorbed by dichloromethane, and injected through gas chromatography column.

The hydrogen flame ionization detector detects and quantifies the retention time, and the peak area or peak height is quantified.

4.2 Instrument

4.2.1 Activated carbon tube, solvent desorption type, containing 100mg/50mg activated carbon.

4.2.2 Air sampler, flow rate from 0mL/min to 500mL/min.

4.2.3 Solvent desorption bottle, 2mL.

4.2.4 Microinjector, 10 µL, 100 µL.

4.2.5 Gas chromatograph with hydrogen flame ionization detector, instrument operation reference conditions.

a) Column. 30m × 0.32mm × 1.0µm, 100% dimethylsiloxane;

b) column temperature. initial temperature 40 ° C, kept for 3 min, heated to 180 ° C at 60 ° C/min;

c) gasification chamber temperature. 250 ° C;

d) detection chamber temperature. 300 ° C;

e) carrier gas (nitrogen) flow rate. 2.0mL/min;

f) Split ratio. 20.1.

4.3 Reagents

4.3.1 Dichloromethane, chromatographic identification of interference-free peaks.

4.3.2 sevoflurane, the mass of 1 L liquid at 1.5 ° C is 1.524 mg.

4.3.3 Isoflurane, the mass of 1L liquid is 1.502mg at 20 °C.

4.3.4 Enflurane, at 20 ° C, the mass of 1 L liquid is 1.526 mg.

4.3.5 Standard solution. Add methylene chloride to the volumetric flask. After weighing accurately, add a certain amount of sevoflurane, isoflurane and/or enfluoride.

The alkane was weighed accurately and made up to volume with dichloromethane. The concentration of the solution was calculated from the difference in weighing and was a standard solution of sevoflurane, isoflurane and enflurane.

Or formulated with a nationally recognized standard solution.

4.4 Sample collection, transportation and storage

4.4.1 On-site sampling shall be performed in accordance with GBZ 159.

4.4.2 Short-time sampling. At the sampling point, a 15 min air sample was collected with an activated carbon tube at a flow rate of 300 mL/min.

4.4.3 Long-term sampling. At the sampling point, an air sample of 2h to 8h is collected with an activated carbon tube at a flow rate of 50 mL/min.

4.4.4 Immediately after sampling, the ends of the activated carbon tube are closed and transported and stored in a clean container. The sample can be stored for 10 days at room temperature.

4.4.5 Sample blank. At the sampling point, open both ends of the activated carbon tube and immediately close it, then transport, store and measure with the sample.

Not less than 2 sample blanks per batch.

4.5 Analysis steps

4.5.1 Sample treatment. Put the activated carbon in the front and back sections into two solvent desorption bottles, add 1.0mL of dichloromethane each, and block the solution.

Soak for 30min, shake it from time to time, and sample solution for measurement.

4.5.2 Preparation of standard curve. Take 4 to 7 volumetric flasks and dilute the standard solution with dichloromethane to 0.0g/mL~300.0g/mL.

The standard range of sevoflurane, isoflurane and enflurane. Adjust the gas chromatograph to the best measurement state according to the operating conditions of the instrument.

Inject 1.0 L and measure the peak height or peak area of each concentration of the standard series. Measured peak height or peak area versus corresponding sevoflurane, isofluoride the alkane and enflurane concentrations (g/mL) are plotted against a standard curve or a regression equation, and the correlation coefficient should be >=0.999.

4.5.3 Sample determination. The peak height or peak area value measured by measuring the sample solution and the sample blank solution using the operating conditions of the standard series.

The concentration of sevoflurane, isoflurane and enflurane in the sample solution (g/mL) was obtained from a standard curve or a regression equation. If the concentration of the analyte in the sample solution Exceeding the measurement range, it is measured by diluting with dichloromethane, and the calculation is multiplied by the dilution factor.

4.6 Calculation

4.6.1 Convert the sample volume to the standard sample volume according to the method and requirements of GBZ 159.

4.6.2 Calculate the concentrations of sevoflurane, isoflurane and enflurane in air according to formula (1).

Vcc

21 )( = ...(1)

In the formula.

C - concentration of sevoflurane, isoflurane and enflurane in air, in milligrams per cubic meter (mg/m3);

C1, c2-- measured concentration of sevoflurane, isoflurane and enflurane in the sample solution before and after (minus sample blank), the unit is micro Grams per milliliter (g/mL);

v -- the volume of the sample solution in milliliters (mL);

V0 -- standard sampling volume in liters (L).

D -- desorption efficiency, %.

4.6.3 The time-weighted average contact concentration (CTWA) in air is calculated in accordance with GBZ 159.

4.7 Description

4.7.1 This method is developed in accordance with the methods and requirements of GBZ/T 210.4. The detection limit, the lower limit of quantification, the scope of quantitative determination, and the most Low detection concentration, minimum quantitative concentration (based on the collection of 4.5L air sample), relative standard deviation, breakthrough capacity (100mg activated carbon), the performance indicators of the average sampling efficiency and the average desorption efficiency are shown in Table 2. The desorption efficiency of each batch of activated carbon tubes should be determined.

Table 2 Performance indicators of the method

Performance

Chemical material

Heptafluoroalkane isoflurane Detection limit/(g/mL) 0.66 0.75 0.71 Lower limit of quantitation/(g/mL) 2.2 2.5 2.4 Quantitative measurement range/(g/mL) 2.2 ~ 300 2.5 ~ 300 2.4 ~ 300 Minimum detectable concentration/(mg/m3) 0.2 0.2 0.2 Minimum quantitative concentration/(mg/m3) 0.5 0.6 0.6 Relative standard deviation /% 1.2 to 4.6 0.9 to 4.1 0.9 to 4.5 Penetration capacity/mg 3.7 3.4 3.4 Average sampling efficiency /% 100 100 100 Average desorption efficiency /% >95 >95 >95

4.7.2 This method can also be measured using equivalent other GC columns. Constant temperature measurement or temperature programmed measurement can be selected according to the measurement requirements.

4.7.3 See Figure 1 for the chromatographic separation of this method. Ethanol, which may coexist in the on-site air, does not interfere with the measurement.

Min0 0.5 1 1.5 2 2.5 3 3.5 4 pA Description.

1--sevoflurane;

2--ethanol;

3--isoflurane;

4--enflurane;

5--dichloromethane.

Figure 1 Chromatographic separation of sevoflurane, isoflurane, enflurane and coexisting materials