Volatiles screening and quantitation – Blood alcohol screening

Blood alcohol screening

What is the level of alcohol in biological fluid? A fair question, both from forensic and law enforcement stand point.

Blood alcohol content (BAC) analysis is one of the most common preliminary tests in forensic science. However, for purposes of law enforcement, blood alcohol content is used to define the level of intoxication and a rough measure of impairment. It is generally performed via headspace gas chromatography (GC) with a flame ionization detector (FID), using a dual-columns/dual-detector configuration for compounds identification confirmation.

The content of alcohol in blood is most commonly expressed as grams per deciliter (g/dL). Find out how to determine blood alcohol levels using the TRACE 1310 GC, the new TriPlus 500 GC Headspace autosampler, and  Chromeleon CDS software solutions.


BAC Analysis workflow

Sample collection and processing

Sample collection

Blood is collected by a phlebotomist in two grey-top tubes that should contain a preservative and anticoagulant (grey top tubes are normally used in medicine for glucose-testing). Typically sodium fluoride is used as preservative. One tube is for the crime lab to test and the other is preserved for the subject’s independent testing purposes. At the crime lab, one tube is opened and the contents are poured into a clean container. A measured amount of blood and a type of alcohol (usually n-propanol) as internal standard are mixed together into a headspace vial, which is then crimp-sealed.

Sample processing

The number of samples run in a day by a forensic lab includes specimen and quality control standards can easily reach several hundreds. Sample preparation often accounts for more than twice the time spent on actual chromatography. Through headspace sampling, it is possible to automate and accelerate organic volatiles determinations to increase sample turnaround and lower the cost per analysis. It is paramount that the system will be able to run many unattended analyses and safely classify and store results.

TriPlus 500 GC Headspace Autosampler

The Thermo Scientific TriPlus 500 GC Headspace Autosampler: Designed for fast startup, high productivity, and maximum flexibility for any lab analyzing organic volatiles.

  • Superior sample integrity and traceability
  • End-to-end inertness of the sample path with direct column connection to the valve and loop manifold
  • Compact design easily upgradable from 12-vial basic configuration up to 240-vial capacity
  • Local control through the friendly GC touchscreen user interface further enhances the system's versatility

GC Headspace

Blood is a very complex biological matrix, which includes salts, proteins, lipids and other metabolites. As such, a direct analysis of blood would result in a very frequent contamination of the GC injector, leading to frequent stops in the working routines and as such very low efficiency. Headspace sampling technique facilitates the extraction of volatiles and provide a "clean" injection in the GC system leading to minimized instrument downtime and overall short time of analysis.

GC Headspace schematic

Typical screening for blood alcohol is done with static headspace extraction coupled with a gas chromatograph in a dual-column/dual-FID configuration. A short uncoated guard column connects, through a 3-port microfluidic connector, to two columns having different polarity, to combine quantitative determination to ID confirmation.


Achieve fast instrument setup for your analytical layout with the easy to install and swap Instant Connect modular injectors and detectors for the TRACE 1300 line of gas chromatography systems.

 Learn more


Additional resources

Consumables

Data Analysis

Simplify your analysis to just a few mouse clicks without sacrificing flexibility using Thermo Scientific Dionex Chromeleon 7.2 Chromatography Data System software. Quick, efficient peak integration with dynamic data linkage and traceability to maintain steady tracking of data at any point during processing.

Chromeleon Software benefits:

  • Dynamic linking of all data, from calibration plots to report tables and charts
  • Compliance ready data management
  • Complete multi-user chromatography management solution
  • Robust and secure file access and storage

Learn how to streamline your laboratory workflow with Operational Simplity and Intelligent Functionality. Chromeleon 7.2 CDS, is the first CDS to include quantitative mass spectrometry control and processing in a client/server environment.

Learn more


Additional resources

Sample collection and processing

Sample collection

Blood is collected by a phlebotomist in two grey-top tubes that should contain a preservative and anticoagulant (grey top tubes are normally used in medicine for glucose-testing). Typically sodium fluoride is used as preservative. One tube is for the crime lab to test and the other is preserved for the subject’s independent testing purposes. At the crime lab, one tube is opened and the contents are poured into a clean container. A measured amount of blood and a type of alcohol (usually n-propanol) as internal standard are mixed together into a headspace vial, which is then crimp-sealed.

Sample processing

The number of samples run in a day by a forensic lab includes specimen and quality control standards can easily reach several hundreds. Sample preparation often accounts for more than twice the time spent on actual chromatography. Through headspace sampling, it is possible to automate and accelerate organic volatiles determinations to increase sample turnaround and lower the cost per analysis. It is paramount that the system will be able to run many unattended analyses and safely classify and store results.

TriPlus 500 GC Headspace Autosampler

The Thermo Scientific TriPlus 500 GC Headspace Autosampler: Designed for fast startup, high productivity, and maximum flexibility for any lab analyzing organic volatiles.

  • Superior sample integrity and traceability
  • End-to-end inertness of the sample path with direct column connection to the valve and loop manifold
  • Compact design easily upgradable from 12-vial basic configuration up to 240-vial capacity
  • Local control through the friendly GC touchscreen user interface further enhances the system's versatility

GC Headspace

Blood is a very complex biological matrix, which includes salts, proteins, lipids and other metabolites. As such, a direct analysis of blood would result in a very frequent contamination of the GC injector, leading to frequent stops in the working routines and as such very low efficiency. Headspace sampling technique facilitates the extraction of volatiles and provide a "clean" injection in the GC system leading to minimized instrument downtime and overall short time of analysis.

GC Headspace schematic

Typical screening for blood alcohol is done with static headspace extraction coupled with a gas chromatograph in a dual-column/dual-FID configuration. A short uncoated guard column connects, through a 3-port microfluidic connector, to two columns having different polarity, to combine quantitative determination to ID confirmation.


Achieve fast instrument setup for your analytical layout with the easy to install and swap Instant Connect modular injectors and detectors for the TRACE 1300 line of gas chromatography systems.

 Learn more


Additional resources

Consumables

Data Analysis

Simplify your analysis to just a few mouse clicks without sacrificing flexibility using Thermo Scientific Dionex Chromeleon 7.2 Chromatography Data System software. Quick, efficient peak integration with dynamic data linkage and traceability to maintain steady tracking of data at any point during processing.

Chromeleon Software benefits:

  • Dynamic linking of all data, from calibration plots to report tables and charts
  • Compliance ready data management
  • Complete multi-user chromatography management solution
  • Robust and secure file access and storage

Learn how to streamline your laboratory workflow with Operational Simplity and Intelligent Functionality. Chromeleon 7.2 CDS, is the first CDS to include quantitative mass spectrometry control and processing in a client/server environment.

Learn more


Additional resources