How will it affect drunk driving testing?, National standard for alcohol testing released
Recently, the national standard for the testing of ethanol, methanol, n-propanol, acetone, isopropanol, and n-butanol in blood and urine has been officially released and will be implemented from March 1, 2024. The "Gold Standard" for alcohol testing has been upgraded after years of practical testing, and its release has received widespread attention. Whether it is due to traffic accidents, drunk accidents, abnormal deaths, or health factors, the results of alcohol testing will be more accurate and fair.
As the drafter of this national standard, Liu Wei, the director of the Forensic Toxicology Laboratory at the Institute of Forensic Appraisal Science, said, "Technical standards are a process of continuous improvement and evolution. The inheritance and transformation of national standards not only aim to further unify and regulate, but also strive to improve their universal applicability."
So, what is the principle of alcohol detection in the national standard? How to ensure the scientific, rigorous, and accurate results? Liu Wei explained that compared to previous public safety industry standards, a major improvement in this national standard is the expansion of alcohol detection methods. The original industry standard only relied on gas chromatography analysis, while the national standard added a combination of chromatography and mass spectrometry technology, which not only added qualitative judgment methods, but also expanded the scope and application areas of the standard, making the detection results more scientific.
"Especially in the field of criminal investigation, suspect 'blood or urine samples usually have complex chemical components, such as alcohol, drugs, drugs, etc. The chromatography/mass spectrometry technology can analyze and identify compounds from the perspective of structural information. The characterization of different types of compounds is helpful to judge suspect' behavior patterns, such as whether they are under the influence of alcohol or poisons, and these evidence clues often play a key role in practice." Liu Wei said.
The national standard also specifies the rigidity requirements for the "double column system". Because different compounds may exhibit the same retention time on a chromatographic column with the same properties, it may lead to misjudgment of the results.
Liu Wei once accepted a judicial appraisal of a major traffic accident, and both personal and physical evidence showed that the driver who caused the accident did not drink alcohol, except for the alcohol test results which showed that his blood contained a certain concentration of ethanol. The investigating authority shall send the blood sample to the Judicial Appraisal Science Research Institute for re appraisal. After using two different chromatographic columns for detection, Liu Wei found that the ethanol component in the driver's blood sample was actually a compound called sevoflurane. The chromatographic behavior of this compound on a certain chromatographic column is similar to that of ethanol, but it will be exposed in its original form on another chromatographic column.
Originally, the driver underwent craniotomy surgery after a car accident, and one of the anesthetic drugs was sevoflurane. The appraisal of this case highlights the importance of dual column testing. "Especially for drivers' alcohol testing, the identification results have a great impact. Even a one in ten thousand chance of misjudgment is a disaster for the parties involved, and what we need to do is to avoid tragedies caused by misjudgment." Liu Wei said.
Accuracy is a prerequisite for fairness, and it is crucial for alcohol testing, judicial appraisal, and the quality of appraisal is even more so. Liu Wei stated that sample management is one of the effective means of quality control. For a long time, the Judicial Appraisal Science Research Institute has adopted a "dual sample" management model for samples. One sample is used for the current practice, and the other is sealed for review. This mechanism ensures standardized identification procedures, thereby ensuring the accuracy and impartiality of identification results.
Every progress in standard development is an inheritance of the work of predecessors and an exploration of the future. Starting from the public safety industry standard for alcohol testing in 1995, it has been involved in local standards, ministerial technical specifications, industry standards for drunk driving, drug driving, etc. in road traffic, and has been a participant and leader in today's national standard. Liu Wei said, "From sample collection and storage, to testing and analysis, and finally to data interpretation, every step of alcohol testing has clear standards. It is not a constraint, but a guide. Let us know how to maintain objectivity and fairness when facing complex practical problems, and how to use scientific methods to find answers. Along the way, we must adhere to the bottom line, be clear in our minds, and have accuracy in our hands."
