|
Abstract INTRODUCTION: Coated Blade Spray (CBS) is a technology that combines sample preparation and direct coupling to mass spectrometry (MS) on a single device. CBS is a coated stainless steel sheet with the shape of a small sword with an ultra-thin SPME coating that permits rapid enrichment of small molecules present in complex samples via free-concentration. As a substrate spray technology, it can generate instrumental signal on a mass spectrometer by supplying a small amount of organic solvent to the coated area of the device and then applying a strong electrical field to the non-coated area of the device, which in turn generates gaseous ions from a the tip of the CBS via electrospray ionization (ESI).
OBJECTIVES: In this work, we explore for the first time its application towards the determination of several controlled-substances/pain-management drugs in oral fluids. As a proof-of-concept, we investigate its applicability to large (>100 µL) and small (<20 µL) sample volumes of OF.
METHODS: Hydrophobic-Lipophilic Balance (HLB) particles were selected as the extraction phase and CBS devices. The CBS analytical protocol comprised three steps: 1.) Analyte-enrichment, by extracting from a 96-well plate containing the samples. 2.) Coating-cleaning, which involved immersing the CBS device in water for fast removal of any loosely attached; and 3.) Instrumental analysis, which is performed by applying 5 µL of a methanol/water onto the coated area. After 10 s, 4 kV were applied to the non-coated area of blade for 5 s, inducing electrospray ionization..
RESULTS: The optimized CBS-MS/MS method enabled outstanding limits of quantitation (≤ 5 ng/mL) for most of the target molecules (e.g. cocaine, fentanyl, EDDP, fluoxetine) in oral fluids. 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. As a proof-of-concept, the method was also examined for the analysis of droplets of oral fluid.
CONCLUSIONS: 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 each of the selected compounds over the range evaluated. Furthermore, it was proven that the methodology could also be applied to small sample volumes such as oral fluid droplets. Our work is currently focused on providing a fully automated platform that can aid in decreasing the total analysis time for 96 samples to under 10 min.
|
= Discovery stage.
= Translation stage.
= Clinically available.
