Microsampling with a Solid-Phase Extraction Cartridge: Storage and Online Mass Spectrometry Analysis

Abstract

This study aims to introduce the concept of utilizing a solid-phase extraction (SPE) cartridge for remote biofluid collection, followed by direct sample analysis at a later time. For this, a dried matrix spot was prepared in a syringe, in the form of SPE cartridge for the first time to enable small biofluid collection (microsampling), storage, shipment, and online electrospray ionization (ESI) mass spectrometry (MS) analysis of the stored dried samples. The SPE sorbents were packed into an ESI syringe and the resultant cartridge was used for sampling small volumes (<20 μL) of different complex biological fluids including blood, plasma, serum, and urine. The collected sample was stored in the dry state within the confinement of the SPE sorbent at room temperature, and analyte stability (e.g., diazepam) was maintained for more than a year. Direct coupling of the SPE cartridge to MS provides excellent accuracy, precision, and sensitivity for analyzing illicit drugs present in the biofluid. The corresponding mechanism of wrong-way positive ion generation from highly basic elution solvents was explored. Without chromatography, our direct SPE-ESI-MS analysis technique afforded detection limits as low as 26 and 140 pg/mL for raw urine and untreated plasma, respectively. These promising results proved that the new syringe-based SPE cartridge can serve as a good alternative to conventional microsampling techniques in terms of analyte stability, ease of operation and versatility, and analytical sensitivity and speed.

High-Throughput Nanoliter Sampling and Direct Analysis of Biological Fluids Using Droplet Imbibition Mass Spectrometry

“…As mentioned before, the traditional methods for analyzing raw biological fluids require extra sample preparation, making the analysis process longer and tedious. , Diluting the biofluids for direct analysis can reduce matrix effects. However, dilution can decrease the sensitivity of the method especially when dealing with ultra-small volumes.…”

In-situ sampling of lipids in tissues using a porous membrane microprobe for direct mass spectrometry analysis

“…In the sampling step, the microprobe was inserted into a tissue sample or rolled on the surface of a tissue sample for about 30 ​s. Since the sampling process did not require reaching extraction equilibrium of the lipids between each phase [ 45 ], the sampling can be completed in a short time. After sampling, a washing step was applied to remove pieces tissues or cells.…”

Direct Analysis of Whole Blood by a Disposable Monolithic Column Mass Spectrometry Analysis Kit†

“…designed a solid‐phase extraction (SPE) cartridge for whole blood analysis. [ 19 ] The whole blood sample was transferred into the SPE cartridge for clean‐up as well as long time storage. Without chromatographic separation, the detection limits of direct MS analysis were as low as 26 and 140 pg/mL for raw urine and untreated plasma, respectively.…”

“…in the kit followed by rapid sample clean‐up in 30 s. The monolithic columns can also avoid analyte exposure to oxygen, moisture and sunlight, which helps the storage of the sample for laboratory analysis. [ 19 ] This method has been successfully applied to the quantitative analysis of procainamide hydrochloride in 2 μL rat blood, which is expected to become a cost‐effective and powerful tool for in vitro diagnostics.…”