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ASMS 2020

ASMS 2020 Reboot

Restek at ASMS 2019
Restek at ASMS 2019

RESTEK TECHNICAL POSTERS:

FRIDAY, JUNE 5
An Alternate Workflow Using Automated In-Line Pigment Removal for the Analysis of Multiresidue Pesticides in Spinach by LC-MS/MS
Sharon Lupo (presenter), Randy Romesberg, Xiaoning Lu
Restek Corporation
For more information, email Sharon Lupo.
Download a PDF of the full presentation.
Play VideoWatch Video | Read abstract

Trueness and precision of the procedure were evaluated by spiking 63 representative pesticides into spinach at 0.005 mg/kg and 0.05 mg/kg. Pesticides with average recoveries (n=6) within 70-120% and RSD values ≤20% for LQC and HQC levels were 86% and 100%, respectively. Calibration curves were prepared in both solvent and matrix at eight levels ranging from 0.0025 – 0.1 mg/kg and injected in duplicate. Matrix effects were determined by dividing the slope of the matrix-matched calibration curve with that of the solvent calibration curve. Low to moderate matrix effects (<50%) were calculated for 95% of the analytes. Performance of the new ILSP workflow was also benchmarked against a traditional QuEChERS extraction and cleanup procedure utilizing AOAC formulated salts and dispersive solid phase extraction (dSPE) sorbents. The results of the new ILSP workflow were comparable to those of QuEChERS while the extraction and cleanup steps of the new workflow required 80% less time and resulted in significantly less pigments reaching the MS source.

Rapid Screening and Confirmation of Target Analytes in Biological Fluids Using a Single Sample and a Single Sampling Collection Device
German Gómez-Ríos (presenter), Shane Stevens, David Bell, Gary Stidsen
Restek Corporation
For more information, email German Gómez-Ríos.
Download a PDF of the full presentation.
Play VideoWatch Video | Read abstract

Coated Blade Spray (CBS) is a technology that allows for analyte collection and direct-to-MS interface from a single device. Essentially, CBS is a coated, stainless-steel sheet with the shape of a small sword which, thanks to its ultrathin coating, permits rapid enrichment of small molecules present in complex samples and ionization via ESI mechanism. In this research, we demonstrate the screening (via direct-to-MS/MS), quantitation, and confirmation (via LC-MS/MS) capabilities of CBS towards the determination of several pain management and controlled substances in urine, blood, oral fluid, and plasma samples.

The CBS-MS/MS analytical protocol was comprised of three steps: (1) analyte enrichment by extracting from a 96-well plate containing the biological fluid (≤ 200 µL); (2) coating cleaning, which involved immersing the CBS device in water for fast removal of any loosely attached matrix components; and (3) instrumental analysis via direct-to-MS/MS first, and, subsequently, via LC-MS/MS. The optimized CBS-MS/MS method demonstrated outstanding precision (RSD<10 %), LOQs equal to or below 5 ng/mL, and excellent linearity (R2 > 0.99) for most of the target molecules (e.g., cocaine, fentanyl, EDDP, fluoxetine) over the range evaluated. Furthermore, it was proven that the methodology could also be applied to small sample volumes such as biofluid droplets. A comparison between the CBS-MS/MS method and the confirmatory test (via LC-MS/MS) showed good agreement (R2 ≥ 0.95) between both approaches for all analytes.

LC-MS/MS Analysis of Glyphosate and Other Polar Contaminants in Food with a Novel Ion-Exchange/HILIC Column
Xiaoning Lu (presenter), Dan Li, Connor Flannery
Restek Corporation
For more information, email Xiaoning Lu.
Download a PDF of the full presentation.
Play VideoWatch Video | Read abstract

One of the major challenges in the direct HPLC analysis of underivatized glyphosate and its metabolites is their minimum retentions on a reversed-phase (e.g., C18) or HILIC (e.g., silica and diol) column. The hybrid ion exchange (IEX)/HILIC column offers different separation mechanisms, i.e., ion exchange and HILIC interactions with ionic polar analytes. It shows high retention and selectivity for glyphosate, AMPA (glyphosate’s metabolite), and glufosinate as well as other polar analytes (see the attached Fig.1). On a relatively short (3 cm) column and under the simple LC-MS conditions, these structurally related polar compounds are well separated, with a retention k’ for glyphosate, AMPA, and glufosinate being about 30, 4, and 16, respectively. Also noted is the symmetric peak shapes for all of the 18 ionic polar analytes, which can be difficult to achieve by other methods.

With the column, a LC-MS/MS method has been developed for the simultaneous detection of glyphosate, AMPA, and glufosinate as well as other polar contaminants in various food matrices, including baby cereal, spinach, strawberry, tea, and wheat. Each analyte was monitored in the negative mode with at least two MRM transitions. The food samples were extracted with the QuPPe methods and directly injected for analysis. It was observed that a small (2.1 mm id x 5 mm L) guard helped in reducing the matrix effects. For a small injection volume (10 µL or less), the limits of detection (LOD) for glyphosate, AMPA, and glufosinate in the spiked food matrices are in the low ppb range, which is lower than the regulated safety residual level of glyphosate in USA and Europe. Further experiments showed the feasibility of achieving a LOD of 20 ppt with a 500 µL injection of water samples.

Analysis of the California List of Pesticides and Mycotoxins in Cannabis Edibles
Nathaly Reyes Garcés (presenter), Colton Myers, Ashlee Gerardi
Restek Corporation
For more information, email Nathaly Reyes Garcés.
Download a PDF of the full presentation.
Play VideoWatch Video | Read abstract

This work describes an effective workflow for the simultaneous analysis of the California list of pesticides and mycotoxins in brownies with only 3 mL of solvent consumed per sample using both LC-MS/MS and GC-MS/MS for instrumental analysis. Multiple experimental parameters were evaluated and valuable lessons were learned over the course of the sample preparation optimization. For instance, it was found that the addition of acetic acid to the extraction solvent enhanced the recovery of daminozide by approximately five-fold. In addition, enhancements in recovery values of about 20% were observed for several analytes by performing a two-step extraction compared to a typical single-step extraction. The use of internal standards and matrix-matched calibration was imperative to obtain a reliable methodology. Overall, the proposed workflow provided excellent results in terms of linearity, accuracy, precision, and limits of quantitation (LOQs).

Coated Blade Spray-Tandem Mass Spectrometry for Rapid Screening and Quantitation of Target Drugs in Oral Fluids and Plasma Samples
German Gómez-Ríos (presenter), Shane Stevens, David Bell, Gary Stidsen
Restek Corporation
For more information, email German Gómez-Ríos.
Download a PDF of the full presentation.
Play VideoWatch Video | Read abstract

In this work, we present a thorough examination of the fundamental parameters behind the operation of CBS, including the following: analyte extraction (e.g., coating chemistry, coating thickness, extraction time); analyte elution (e.g., elution time, elution solvent); and ionization conditions (e.g., applied voltage, distance to the MS inlet). As a proof-of-concept, plasma and oral fluid samples were selected as matrices under study. A panel of substances with different physicochemical properties were selected as target compounds to enable a better understanding of each of the steps in the analytical workflow. Our results demonstrated that best extraction times must be selected on the basis of signal-to-noise ratios rather than mere instrumental signal as when compared to SPME coupled to LC-MS. Likewise, the selection of the extraction, elution, and ionization conditions must be done with an awareness of possible synergies among them. Design of the experiments proved to be fundamental to understand best conditions for specific analyte-matrix pair.

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