GBZ/T 313.1-2018Determination of trimethyltin chloride (TMT) in urine -- Part 1: Gas chromatographic method (English PDF)

Foreword

This standard is formulated in accordance with the Law of the People's Republic GBZ/T 313 "Determination of Trimethyltin Chloride in Urine" is divided into two parts.

-- Part 1. Gas chromatography;

-- Part 2. Gas chromatography-mass spectrometry.

This part is the first part of GBZ/T 313.

This part is drafted in accordance with the rules given in GB/T 1.1-2009.

This section drafted by. Guangdong Provincial Occupational Disease Prevention and Control Institute, Shenzhen Occupational Disease Prevention and Control Institute, Shenzhen Luohu District Center for Disease Control and Prevention, Shenzhen Longgang District Center for Disease Control and Prevention.

1 Scope

This part of GBZ/T 313 specifies gas chromatography for the determination of trimethyltin chloride in urine.

This section applies to the determination of trimethyltin chloride in the urine of occupational contacts.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only the dated version applies to this article.

Pieces. For undated references, the latest edition (including all amendments) applies to this document.

General rules for biological monitoring of GBZ/T 295 occupational population WS/T 97 urinary creatinine spectrophotometric method WS/T 98 urinary creatinine by reversed-phase high performance liquid chromatography

3 Principle

Trimethyltin chloride in urine is derivatized with sodium tetraethylborate to trimethylethyltin, extracted with n-hexane, gas chromatograph the detector (sulfur filter) is detected and characterized by retention time and peak area is quantified.

4 Instruments

4.1 stoppered polyethylene plastic bottle, 50mL.

4.2 Centrifuge, 0r/min ~ 3000r/min.

4.3 Microinjector, 1µL, 10µL, 50µL, 100µL.

4.4 Plug glass tube. 15mL with PTFE sealing cap.

4.5 vortex oscillator.

4.6 Gas Chromatograph, Flame Photometric Detector (Sulfur Filter).

Instrument operation reference conditions.

- Column. 30 m × 0.32 mm × 0.25 µm diphenyl-95% dimethyl siloxane copolymer (HP-5);

- column temperature. initial temperature 50 ° C, maintained for 7.0 min, raised to.200 ° C at 20 ° C/min;

-- inlet temperature. 250 ° C;

--Detector temperature..200 ° C;

- hydrogen flow. 50mL/min;

-- Air flow. 60mL/min;

- carrier gas (nitrogen) flow rate. 1.0mL/min;

- Split ratio. 5.1.

5 Reagent

5.1 The experimental water is deionized water.

5.2 Trimethyltin chloride, excellent grade ( >99.8%).

5.3 sodium tetraethyl borate, excellent grade pure.

5.4 Tetrahydrofuran, analytically pure.

5.5 Sodium acetate, analytically pure.

5.6 Glacial acetic acid, analytically pure.

5.7 n-hexane, chromatographically pure.

5.8 Derivatizing agent. Weigh 0.1 g of sodium tetraethyl borate and dissolve it in 10 mL of tetrahydrofuran to prepare 1% sodium tetraethylborate-tetrahydrofuran.

The solution is stored in a refrigerator at 4 ° C in the dark and stable for 1 month.

5.9 Buffer (pH 4.0 ± 0.2). Add 0.6 g of sodium acetate to 120 mL of water, followed by 1.4 mL of glacial acetic acid.

5.10 Standard solution. Add a small amount of water to a 10mL volumetric flask. After weighing accurately, add a certain amount of trimethyltin chloride.

Weighing, add water to the scale; calculate the concentration of this solution from the difference of 2 weighings, which is the standard stock solution (concentration is about 5mg/mL), this solution is at 4°C it can be stored in the refrigerator for 6 months. Dilute to 50.0 µg/mL Trimethyltin chloride standard solution with water before use. Or purchase certified by the state and A standard solution substance that is awarded a standard substance certificate.

6 Sample collection, transportation and storage

A 50-mL random urine sample of workers exposed to trimethyltin chloride is collected in a polyethylene plastic bottle and transported at room temperature or refrigerated.

Store in a 4°C refrigerator and store samples for 15 days.

7 Analysis steps

7.1 Determine urinary creatinine concentration by WS/T 97 or WS/T 98.

7.2 Sample treatment. Shake the urine sample, pipette 5.0 mL of urine sample into 15 mL stoppered glass tube, and add 5.0 mL buffer solution and 0.2 mL respectively.

The derivatizing agent and 1.0 mL of n-hexane were shaken in a vortex shaker for 5 min. After standing or centrifuging, the upper organic phase was analyzed by 1.0 µL. If the concentration of trimethyltin chloride in the sample exceeds the measurement range, and it can be measured by diluting with n-hexane. The calculation is multiplied by the dilution factor.

7.3 Reagent blank treatment. replace the urine sample with 5.0mL water, and treat the sample as the reagent blank.

7.4 Preparation and determination of standard series solution. Add 5.0mL water to 15mL plugged glass tube, then add standard solution to make content for the standard solution of trimethyltin chloride from 0.0g to 2.5g, add 5.0mL buffer and 0.2mL derivative to each standard series solution.

The crude agent and 1.0 mL of n-hexane were shaken in a vortex shaker for 5 min, and the mixture was allowed to stand or centrifuged, and then the upper organic phase was analyzed by 1.0 µL. Reference Under the operating conditions of the instrument, the gas chromatograph was adjusted to the optimal measurement state, and 1.0 µL of n-hexane extract was separately injected to determine each standard series.

Solution. A standard curve is plotted against the corresponding peak area value for the corresponding trimethyltin chloride content (g) or a regression equation is calculated.

7.5 Sample determination. Determine the peak area of the sample and reagent blanks using the operating conditions of the standard series of solutions, from the standard curve or the regression the content of trimethyltin chloride (g).

8 Calculation

The concentration of trimethyltin chloride in urine is calculated according to formula (1).

kDV

In the formula.

C--the concentration of trimethyltin chloride in urine, in micrograms per gram of creatinine (g/g creatinine);

M--the content of trimethyltin chloride in urine (minus the reagent blank) in micrograms (g);

V -- the volume of the urine sample taken in milliliters (mL);

D--recovery of trimethyltin chloride in urine, %;

K--urinary creatinine concentration in grams per liter (g/L).

9 Description

9.1 The detection limit of this method is 0.007g, the lower limit of quantification is 0.035g, and the minimum detectable concentration is 1.4g/L (based on 5.0mL of urine sample).

The minimum quantitative concentration was 7.0 g/L (based on 5.0 mL of urine sample). The measurement range is from 0.007 µg to 2.500 µg, and the relative standard deviation is 0.6%.

9.2 The average recovery rate of this method is 96.7%.

9.3 This method can use other capillary columns with similar performance.

9.4 Dimethyltin dichloride and methyl tin trichloride coexisting with trimethyltin chloride in urine do not interfere with the determination.

9.5 There is no time limit for urine sample collection. Trimethyltin chloride is slowly and constantly excreted in urine. It can collect random urine from workers.

Line detection.

9.6 The quality assurance of the inspection is in accordance with GBZ/T 295.

9.7 The chromatogram is shown in Figure 1.

Note.

1--trimethylethyltin (5.687 min);

2-dimethyldiethyltin (8.681 min);

3--Triethylmethyltin (10.675 min).

Figure 1 Separation diagram of trimethyltin chloride derivative, dimethyltin dichloride derivative and methyltin trichloride derivative

8.681