Analysis of ethanol in blood by Thermo Scientific Air Liquid Chromatography

Keywords: HS-GC, ethanol, blood

introduction

In recent years, with the increasing number of motor vehicles in China, the traffic accidents caused by driving motor vehicles have increased year by year. Among them, traffic accidents caused by drinking or drunk driving account for a large part, and most of them are vicious accidents. Hidden dangers for public safety. To this end, China’s "Road Traffic Safety Law" Article 91 stipulates that if a motorized vehicle is driven after drinking alcohol, and civil liability is pursued, and the drunk driving motor vehicle is restricted by the traffic control department of the public security organ to wake up and revoke the motor vehicle driving. The card is investigated for criminal responsibility according to law. According to the standard, it is determined not to be based on the conscious state of the actor, but to determine the alcohol content in the blood: the vehicle driver's blood alcohol content is greater than or equal to 20mg/100mL, less than 80mg/100m1. It belongs to drunk driving; if the blood alcohol content is greater than or equal to 80mg/100m1, it is drunk driving. At present, accurate detection of alcohol content in human blood is performed internationally by headspace chromatography. With the implementation of the new "Traffic Law", the detection of blood alcohol content in motorists is becoming more and more common. The legal and quantitative detection of blood alcohol content in gas chromatography is the only means of judicial identification. This paper is based on the "People's Republic of China Public Safety Industry Standards" (GA/T849-2009) developed by headspace gas chromatography for the determination of ethanol content in the blood [1]. The program has advanced detection methods, reasonable instrument configuration, simple operation and reliable results, which can be used for reference by public security departments and judicial appraisal centers at all levels.

Experimental part

Main equipment and reagents

Instrument: Trace GC 1310 Gas Chromatograph (ThermoFisher), Triplus 300 Headspace Autosampler.
Reagents: tert-butanol, ethanol;
Sample: human blood sample after drinking

Preparation of control solution and test solution

Control solution: draw 10.04mL or weigh 8.008g of absolute ethanol standard in a 100mL volumetric flask, add purified water to the scale, mix, get 8000mg/100mL ethanol stock solution, and dilute the stock solution to obtain a concentration of 400mg /100 mL of control stock solution. The control stock solution was diluted stepwise to obtain a series of concentration control working solutions at concentrations of 200 mg/100 mL, 100 mg/100 mL, 80 mg/100 mL, 20 mg/100 mL, and 10 mg/100 mL, respectively. Internal standard working solution: Accurately weigh 1.050g t-butanol standard (content not less than 99.5%) in a 500mL volumetric flask, add purified water to the scale, and mix to obtain 200mg/100mL t-butanol standard use solution.

Preparation of samples to be tested and spiked recovery samples

Pipette 0.50mL of whole blood to be tested, add them to the sample bottles, add 0.10mL of t-butanol standard use solution, seal and mix, and wait for injection. 0.494mL of whole blood to be tested, 3 parts in parallel, 6μL of ethanol standard solution of 2000mg/100mL, respectively, and 0.10mL of t-butanol standard use solution were added separately, and operated in parallel according to the above method.

Sample determination

Instrument conditions are shown in Table 1.

result

Linear relationship of methods

Take 0.5 mL of the series concentration standard solution under 2.2, add 0.1 mL of tert-butanol internal standard solution, seal and mix. The samples were injected from low concentration to high concentration, and the ethanol peak area and the internal standard t-butanol peak area ratio were plotted on the ordinate, and the ethanol concentration was plotted on the abscissa as a standard curve. The results showed that the target ethanol and the internal standard t-butanol peak shape (Fig. 1), and the ethanol showed a good linear relationship in the range of 10 mg/100 mL to 200 mg/100 mL (R2=0.9993, see Fig. 2).

Determination of method precision and recovery

Prepare 3 spiked samples according to the method of 2.3, mix and inject after sealing. The obtained sample is shown in Figure 3. The results are shown in Table 2. The recovery range is 91.32~115.40%, relative standard deviation (RSD, n=3). It is 2.55%. The recovery and precision data results are shown in Table 3.

Sample detection

Take two samples under 2.3 and put into the headspace to check the content of ethanol in the blood. The results of two parallel samples are 98.79mg/100mL and 102.18mg/100mL respectively. According to the standard, the average value is in the sample. Its alcohol content is 100.49mg/100mL, which can be designated as drunk driving.

in conclusion

The method according to the steps of GA/T842-2009, combined with Thermofisher's Triplus 300 and Trace 1310 gas chromatograph, detects the alcohol in the blood, and has been verified, the method is simple, rapid and accurate; Forensic Identification Center reference.

references

[1] GA/T842-2009 Method for testing blood alcohol content of public sector standards of the People's Republic of China

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