Rapid Screening & Confirmation of Analytes in Biofluids Using a Single Sample and Sampling Device

Description

There is a need for mass spectrometry based analytical workflows that facilitate rapid screening and quantitation of target analytes in biological fluids. In an ideal world, the same sample can be used for both screening and confirmation. However, in most cases, two independent samples and sample-prep workflows are needed to isolate the target analytes for the screening, quantitation and confirmation steps. 

In this poster video, we present a technology that can be used to capture target compounds from diverse biofluid samples and perform rapid screening and quantitation via direct-to-MS experiments. In addition, the same device can be used for confirmation of said analytes via LC-MS/MS without further sample preparation. This novel technology, known as “coated blade spray” (CBS), provides reliable and reproducible results and with a total analysis time under 5 minutes for the rapid screening protocol.

Additional Resources

• Download a PDF of the full presentation
• Want to know more about Restek coated blade spray (CBS) technology? Sign up today at  https://www.restek.com/cbs

Transcript

Hello, my name is German Gomez and I work at Restek in the research and development team, and I’m going to present my poster "Rapid Screening and Confirmation of Target Analytes in Biological Fluids Using a Single Sample and a Single Sampling Collection Device."

There is need for mass spectrometry-based analytical workflows that facilitate rapid screening and quantitation of target analytes in biological fluids. In an ideal world, the same sample can be used for both screening and confirmation. However, in most cases, two independent samples and sample-prep workflows are needed to isolate the target analytes for the screening, quantitation, and confirmation steps.

Herein, we present a technology that can be used to capture target compounds from diverse biofluid samples and perform rapid screening and quantitation via direct-to-MS experiments. In addition, the same device can be used for confirmation of said analytes via LC-MS/MS without further sample preparation. This novel technology, known as “coated blade spray” or CBS, provides reliable and reproducible results and with a total analysis time under 5 minutes for the rapid screening protocol.

So, what is Coated Blade Spray?

Coated blade spray is an SPME-based analytical technology that facilitates collection of analytes of interest from a sample and the direct interface to mass spectrometry systems via a substrate spray ionization. The device comprises a thin, flat sheet with a pointed tip and is manufactured of a conductive substrate such as stainless steel.

As an SPME device, the substrate is partially coated with an extraction phase comprised of polymeric particles and a binder. The function of the polymeric particles is to enrich the analytes of interest from the sample matrix, while collecting the least amount of interferences.

As a direct-to-MS technology, the device requires a pre-wetting of the extraction material so to elute the analytes collected on it. Subsequently, a differential potential is applied between the non-coated area of the substrate and the inlet of the MS system generating an electrospray at the tip of the CBS device.

CBS devices coated with HLB particles were used in this work, and the CBS analytical protocol comprised three steps: First, analyte enrichment, by extracting from a vial containing the sample of interest. Second, coating cleaning, which involved immersing the CBS device in a vial with water for fast removal of any loosely attached matrix components; and third, instrumental analysis, which is performed by applying 10 µL of methanol/water onto the coated area. After 10 seconds, 4 kV were applied to the non-coated area of blade for 5 seconds, inducing electrospray ionization.

For confirmatory purposes, after running the direct-to-MS analysis, the same CBS device was immersed on a vial containing 200 µL of a methanol/water solution for 5 minutes. One microliter of this solution was injected onto the LC-MS/MS system, and analytes were separated under 3 minutes with a Raptor Biphenyl 30 x 2.1 mm column with 1.8 µm particles.

As can be seen in figure 1, excellent linearity, precision, and accuracy were obtained for different drugs tested such as cocaine, methadone, PCP, and JHW-015 spiked in oral fluids from 1-200 ng/mL. As expected, CBS proved to be a great tool for rapid screening and quantitation of drugs of abuse in oral fluids. While rapid screening is ideal for most applications; confirmatory results with a gold-standard technique is ideal. To the best of our knowledge, this is first time that a device that was used for ultrafast screening can also be used for confirmatory purposes. Figure 2, for example, portrays the chromatogram of several analytes with diverse physicochemical properties that were extracted with the CBS devices from the oral fluid samples. It is important to highlight that, although is not presented in the slide, identical quantitation results were obtained with direct-to-MS approach and the traditional LC-tandem mass spectrometry approach.

In this work, we present the first sampling device that can be used for both rapid screening and quantitation and confirmation and quantitation without further sample preparation. The optimized direct-to-MS method demonstrated outstanding precision with relative standard deviation <10 %, limits of quantitation equal to or below 5 ng/mL and excellent linearity with correlation coefficients >0.99 for each of the selected compounds over the range evaluated between 1-200 ng/mL.

Thank you for watching my poster. If you would like more information about CBS please see the link below and follow us on twitter.