Restek

Restek at AAFS 2025

From analyzing whole blood to separating delta 8 and delta 9, our forensic experts understand the importance of your analysis. We're here to help.

  • Need to separate delta-8 and delta-9-THC? Take advantage of our decades of experience with app notes, chromatograms, and more—all tailored for this analysis.
  • Analyzing whole blood? Our Resprep SPE products have the rugged and reproducible performance you need.
  • Performing analysis of oral fluid or urine? Restek Biphenyl LC columns feature increased sensitivity and faster run time compared to C18s.
Presentations Solutions Speak to an Expert Enter Raffle!

Solutions for Forensics Analysis

Learn from Restek's forensics team with this curated selection of articles, blog posts, and more. Want to learn more? Access our full resource hub.

Fast Analysis of Δ8-THC, Δ9-THC, and Isomeric Hydroxy and Carboxy Metabolites in Whole Blood by LC-MS/MS

Separate Δ8-THC, Δ9-THC, and their isomeric hydroxy and carboxy metabolites quickly and completely with this method for analyzing whole blood samples. Read Now→

The Advantage of 2.1 mm ID Columns for LC-MS/MS Analysis of Drugs of Abuse

Using an LC column with a biphenyl phase lends superior selectivity over a C18 for drugs of abuse (DOA) panels, but choosing the right column dimension is key to obtaining robust and accurate data. In this article, the advantage of narrow-bore LC columns is discussed and demonstrated for drugs of abuse. Read Now→

Fast, Definitive Data for Blood Alcohol Testing on Rtx-BAC Plus 1 and Rtx-BAC Plus 2 Columns (PDF)

Rtx-BAC Plus 1 and Rtx-BAC Plus 2 columns provide definitive data in a fast, two-minute analysis, so you can be certain of your results, maximize sample throughput, and get accurate, reliable results quickly, which is is critical for analyzing blood alcohol concentration (BAC). Read Now→

The Evolving Landscape of THC Drug Testing

In the US, different states have different laws for delta-9-THC products ranging from recreationally legal in some states to illegal in others. This opens the door for other isomers that exist in a legal gray area to be sold on the market for users to get psychoactive effects until the laws are introduced to regulate a specific isomer. A common isomer of delta-9-THC that also has psychoactive effects, is delta-8-THC. Read Now→

Reduce Downtime and Cost of Materials with Rugged Rxi-5Sil MS GC Columns

Restek's Rxi-5Sil MS columns produce consistent results for amphetamine—even after 400 injections of derivatizing reagent—resulting in less time and money spent on column maintenance and replacement. Read Now→

Method Development Guide for Novel Psychoactive Substances

The rise of novel psychoactive substances (NPS) has created a unique challenge for laboratories performing toxicology or seized drug analysis. In this article, consideration will be outlined, both practical and analytical, when working with NPS. Read Now→

New Pro EZGC Library Drugs of Abuse (and TMS-derivatives) on the Rxi-5Sil MS

Restek maintains Pro EZGC libraries of common drugs of abuse that may exist in samples to help customers effortlessly refine methods in less time. This can be especially helpful for resolving coelution between known and unknown compounds. Read Now→

 

Liquid Chromatography

Biphenyl Columns→
Increased sensitivity and faster run times compared to a C18 make biphenyl LC columns ideal for the analysis of whole blood samples.

FluoroPhenyl Columns→
Featuring multiple retention mechanisms, fluorophenyl LC columns can provide better separations than C18s.

Pro EZLC Chromatogram Modeler→
Develop and optimize drugs of abuse methods in minutes with this free and powerful software.

Restek LC column.

Gas Chromatography

Rxi-5Sil MS Columns→
Excellent general-purpose columns with high inertness and low-bleed—ideal for MS.

Rtx-BAC Plus Columns→
Baseline separate all blood alcohol compounds in blood, breath, or urine in under two minutes.

Topaz Inlet Liners→
Exceptional deactivation, reproducibility, and productivity.

Pro EZGC Chromatogram Modeler→
Develop and optimize GC methods in minutes with this free and powerful software.

Restek fused silica GC column.

Sample Preparation

SPE→
Remove phospholipids and proteins in a single, simple procedure with Resprep PLR SPE.

Resprep Sample Prep Products→
Get proven quality, superior cleanliness, and method-specific performance.

Restek Resprep PLR SPE products.

Reference Standards

Delta-8-THC→

Delta-9-THC→

BAC Resolution Control Standard n-P→

BAC Resolution Control Standard t-B→

Restek reference standard ampul.


Back to Top

Presentations

Advances in Sample Preparation Workflows for Oral Fluid Analysis

Wednesday, February 19 from 2:00-2:30 p.m., Exhibit Hall AB
Presenters: Samantha Herbick and Jared Burkhart

View Details

The analysis of drugs of abuse in oral fluids is a solution that is gaining popularity due to its less invasive collection technique as compared to blood or urine collection. However, there are some issues with the buffer used in the collection devices for oral fluid testing. It is often difficult to remove all of the surfactants from the buffer, which can cause matrix effects. Oftentimes solid phase extraction or lengthy extraction techniques are utilized. Finding a method that uses a simple sample preparation paired with accurate and robust quantitation of the analytes is important for laboratories running these tests. An LC-MS/MS method was developed for the quantitation of these compounds using a Raptor Biphenyl 50 x 2.1 mm, 2.7 µm analytical column equipped with a Raptor Biphenyl EXP 5 x 2 mm, 2.7 µm guard column. Samples were prepared in oral fluid and combined with Quantisal buffer. Samples were tested using three different sample preparation techniques: salt-assisted liquid-liquid extraction (SALLE); supported liquid extraction (SLE); and dilute and shoot. The results of these extraction techniques were investigated and compared using recovery, linearity, matrix effects, and accuracy and precision.

 

Comparison of Sample Preparation Techniques for the Analysis of Drugs of Abuse in Oral Fluids

Wednesday, February 19 from 7:30-9:00 p.m., L15
Presenter: Samantha Herbick

View Details

Testing for drugs in biological matrices is an important part of toxicology and workplace drug testing. The “gold standard” matrices that have been used for decades are blood and urine; however, the collection of these fluids is invasive. The analysis of drugs of abuse in oral fluids is gaining popularity due to its less invasive collection technique compared to blood or urine. However, there are some unique challenges associated with oral fluid testing. It can be difficult to remove all of the surfactants and preservatives present in the oral fluid collection device's buffer solution which can cause matrix effects and poor column lifetime. It is also difficult to get complete recovery for all of the analytes because of varying techniques to empty the sponge in the collection device. Oftentimes solid phase extraction or lengthy extraction techniques are utilized. Finding a method that uses a simple sample preparation paired with accurate and robust quantitation of the analytes is important for laboratories running these tests.

LC-MS/MS method was developed using a biphenyl stationary phase. Mobile phase A consisted of 0.1 % formic acid in water and mobile phase B consisted of 0.1% formic acid in methanol. The analytes were separated under gradient conditions with a total cycle time of 10 minutes. This method utilized both positive and negative ESI modes. Samples were prepared in oral fluid and combined with Quantisal buffer. Samples were tested using three different sample preparation techniques: salt-assisted liquid-liquid extraction (SALLE); supported liquid extraction (SLE); and dilute-and-shoot.

A total of 68 drugs of abuse and novel psychoactive substances were analyzed in oral fluid. The chromatographic method was able to separate all sets of isobars. Aliquots were tested using SALLE, SLE, and dilute-and-shoot. The results of these extraction techniques were investigated and compared using performance metrics such as recovery, linearity, matrix effects, and accuracy and precision. It was found that the SALLE sample preparation worked best for a broader list of analytes. The SLE approach worked well for most analytes, but the analyte's performance was highly dependent on the analyte's properties, such as polarity. Dilute and shoot is an easy and cheap technique, but it did not work as well as they other techniques to remove buffer surfactants, leading to issues with analyte performance and column lifetime downstream. It was also difficult to achieve certain limits of detection using the dilute and shoot method. Overall, this work demonstrates an accurate and robust chromatographic method, along with comparisons on the sample preparation techniques.

 

The Development of a Virtual Liquid Chromatography Method Development Tool

Friday, February 21 from 11:30 a.m.-1:00 p.m., B166
Presenter: Haley Berkland, MS

View Details

The development and optimization of liquid chromatography (LC) separations can be time-consuming and costly, often requiring several steps, including literature research, column selection, method scouting, method development, and method optimization. In an effort to eliminate these steps, an instrument-free, software modeling tool that gives users the ability to select compounds from a database and instantly model a separation on different column stationary phases was developed. Optimization of the model can be performed while maintaining critical pair separations by adjusting for instrument/system effects (e.g., dwell volume and extra column volume); mobile phase preferences; number of gradient steps; and more. The initial database consists of a Drugs of Abuse (DoA) library containing approximately 250 compounds with plans to continually expand the utility.

To build the chromatogram modeler, a DoA library containing approximately 250 compounds was created. Data was collected using a standard HPLC system coupled to a triple quadruple mass spectrometer (LC-MS/MS). Retention times were first collected using a fast/slow gradient; 30°C/60°C column temperature points; and ACN/MeOH mobile phases on a single column dimension (50 x 2.1 mm, 2.7 µm). Some additional data points outside of these runs were also collected for the development of a semiempirical correction factor that was used to improve modeling accuracy. To assess the accuracy of the modeler, experiments comparing compound retention time values between wet-lab and modeled data were conducted. After the initial DoA library was built, the modeler was evaluated over four increasingly more complex stages of verification. In the final, most complex stage, new compounds not previously part of the initial DoA library were added and then compared by testing two different column dimensions, two different columns lengths, two different mobile phases, two different stationary phases, three different gradients programs, and three different temperatures against modeled retention time values. Because the semi-empirical correction factor was developed using only the original library compounds, this stage assessed the viability of adding future compounds to existing libraries.

During software development, the acceptance criteria for retention time agreement between wet-lab and modeled values was set at +/- 15 seconds. This range was chosen because it represents a typical MRM window. In the most complex portion of the verification, 704 retention time data points were collected in total for the 25 compounds used in the evaluation. Only 13 data points exceeded the +/- 15 second window with no compounds missing acceptance criteria by more than five seconds, giving an overall pass rate of 98.2%.

An online chromatographic modeling tool was successfully developed that allows users to select columns and compounds for separation. A modeled chromatogram and instrument-ready conditions are automatically generated and can be further optimized by users.


Back to Top

CFOT4425-UNV