GBZ/T 318.2-2018Determination of trimethyltin chloride (TMT) in blood -- Part 2: Gas chromatographic-mass method (English PDF)

Foreword

This standard is formulated in accordance with the Law of the People's Republic GBZ/T 318 "Determination of Trimethyltin Chloride in Blood" is divided into two parts.

-- Part 1. Gas chromatography;

-- Part 2. Gas chromatography-mass spectrometry.

This part is the second part of GBZ/T 318.

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

This standard was drafted. 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 318 specifies the determination of trimethyltin chloride in the blood by gas chromatography-mass spectrometry.

This standard applies to the determination of trimethyltin chloride in the blood 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.

GBZ/T 295 General rules for occupational health biological monitoring

3 Principle

Trimethyltin chloride in the blood is derivatized with sodium tetraethylborate to trimethylethyltin, extracted with n-hexane, and detected by gas chromatography-mass spectrometry.

It was characterized by the retention time and the abundance ratio of the characteristic ions, and quantified by the ion abundance value (peak area) of the characteristic ions of 165 m/z.

4 Instruments

4.1 Heparin sodium anticoagulation blood collection tube, 5mL.

4.2 Centrifuge, 0 r/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 Chromatography-Mass Spectrometer.

Instrument operation reference conditions.

a) Chromatographic conditions.

- Column. 60 m × 0.32 mm × 1.0 µm diphenyl-95% dimethyl siloxane copolymer (HP-5MS);

- Column temperature. initial temperature 50 °C, rise to.200 °C at 20 °C/min, keep 1.0min;

-- vaporization chamber temperature. 250 ° C;

-- Column flow. 2.0 mL/min;

- Split ratio. 5. 1.

b) Mass spectrometry conditions.

--Ion source. electron bombarded ion source (EI);

--Ionization energy. 70eV;

--Ion source temperature. 230 °C;

-- Interface temperature. 260 ° C;

-- Scan mode. Select ion scan mode, select 165 m/z as quantitative ion, 151m/z, 165m/z, 179m/z and 194 m/z to identify ions;

-- Solvent delay time. 4.0 min.

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 Acetonitrile, chromatographically pure.

5.9 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.

5.10 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.

5.11 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

Use heparin sodium anticoagulant blood collection tube to collect 5 mL of blood sample of workers exposed to trimethyltin chloride, transport at room temperature or refrigerated, and place it at 4 ° C as soon as possible.

Stored in the box, the sample can be stored for 15d.

7 Analysis steps

7.1 Sample Handling. Remove the blood sample from the refrigerator, set it back to room temperature, and shake well. Accurately draw 1.0 mL of blood sample at 15 mL in a stoppered glass tube, add 2.0 mL of buffer solution, shake well, add 7.0 mL of acetonitrile, seal and shake for 1 min to fully precipitate the protein, then Centrifuge at 3000r/min for 1min, transfer the supernatant to another 15mL glass tube, add a small amount of acetonitrile to wash the precipitate, and combine the washing solution was placed in a 15 mL stoppered glass tube, and 0.2 mL of the derivatizing agent was added. After mixing, 1.0 mL of n-hexane was accurately added, and the mixture was shaken for 5 minutes after sealing.

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, n-hexane can be used.

Determined after dilution and multiplied by the dilution factor.

7.2 Reagent blank treatment. Replace the blood sample with 1.0mL water, and treat the sample as the reagent blank.

7.3 Preparation and determination of standard series of solutions. Add 1.0 mL of water to a 15 mL stoppered glass tube, and then add a standard solution to prepare the content.

For the standard solution of trimethyltin chloride from 0.0g to 2.5g, add 2.0mL of buffer solution to each standard series solution, shake and add Into 7.0mL of acetonitrile and 0.2mL of derivatizing agent, after mixing, accurately add 1.0mL of n-hexane, seal and shake for 5min, after standing or centrifugal layering A 1.0 µL analysis of the upper organic phase was taken. Adjust the gas chromatograph-mass spectrometer to the best measurement state according to the operating conditions of the instrument, and inject 1.0 µL respectively.

The n-hexane extract was used to determine each standard series of solutions. The ion abundance value (peak area) of the measured 165 m/z characteristic ion is corresponding to the trimethyltin chloride content (g) is plotted against a standard curve or a regression equation.

7.4 Sample determination. Determination of the ion abundance value of the sample and reagent blanks at 165 m/z using the operating conditions of the standard series of solutions (peak surface) Product), the content of trimethyltin chloride (g) is obtained from a standard curve or a regression equation.

8 Calculation

Calculate the concentration of trimethyltin chloride in the blood according to formula (1).

In the formula.

C--the concentration of trimethyltin chloride in the blood, in micrograms per liter (g/L);

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

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

D--Recovery of trimethyltin chloride in blood, %.

9 Description

9.1 The detection limit of this method is 0.003g, the lower limit of quantification is 0.015g, and the minimum detectable concentration is 3.0g/L (based on the blood sample 1.0mL).

The lowest quantitative concentration was 15.0 g/L (based on a blood sample of 1.0 mL). The measurement range is from 0.003 µg to 2.500 µg, and the relative standard deviation is 1.1%.

9.2 The average recovery rate of this method is 76.6%.

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 the blood do not interfere with the determination.

9.5 There is no time limit for the collection of blood samples. Since trimethyltin chloride is mainly distributed in red blood cells, it cannot be detected by plasma.

Whole blood sample testing should be used.

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

9.7 Chromatograms and mass spectra are shown in Figures 1 to 3.

Note.

1--trimethylethyltin (4.98 min);

2-dimethyldiethyltin (5.98 min);

3--Triethylmethyltin (6.98 min).

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

Figure 2 Mass spectrum of trimethyltin chloride

Figure 3 Mass spectrum of trimethyltintin derivative of trimethyltin chloride

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