A Sensitive and High-Throughput Lc/MS/MS Method Using a Silica Column and an Aqueous-Organic Mobile Phase for the Analysis of Fluoxetine and Norfluoxetine in Human Plasma

Simple means to alleviate sensitivity loss by trifluoroacetic acid (TFA) mobile phases in the hydrophilic interaction chromatography–electrospray tandem mass spectrometric (HILIC–ESI/MS/MS) bioanalysis of basic compounds

“…TFA is volatile and therefore can be used in LC-MS, and it has been used in the LC-MS analyses of peptides [4] as well as small molecules [5]. Our research group has also been using bare silica column operated under hydrophilic interaction chromatography (HILIC) mode with TFA-containing mobile phases for the LC-MS analyses of small molecules in biological matrices [6][7][8][9][10][11]. The major drawback of using TFA in LC-MS, however, is that TFA is known to suppress the ESI signals of analytes and reduce assay sensitivity [12,13].…”

Fast LC/MS in the analysis of small molecules

“…HILIC (described in greater detail in the gradient section in this review) has been employed for the analysis of polar analytes from plasma [80,140,141,142,143,144,145,146,147,148,149,150]. Using post-column infusion, Brown et al [148] demonstrate ion suppression does not occur in the region of analyte elution for samples prepared using protein precipitation in conjunction with a HILIC separation.…”

“…Fully automated 96-well methods have been put into operation for liquid-liquid extractions [22,165] and liquid-solid extractions [166]. Fully automated SPE is the most prevalent form of automation and has been used for the analysis of multiple species plasma and urine samples [80,142,143,144,145,167,168,169] and in conjunction with cassette-dosed pharmacokinetic animal studies [170]. Barbarin et al [171], use automated 96-well rat plasma protein precipitation on a monolith column at 3.5 mL min -1 for a 17-s injection-to-injection analysis.…”

Potential of HILIC‐MS in quantitative bioanalysis of drugs and drug metabolites

“…The chromatographic run time was 2.0 min per injection with a LOD of 0.05 ng/mL. Similar methodologies using different MRM were further extended for the determinations of tiapride [37], clonidine [38], fluoxetine, norfluoxetine [39], fluconazole [40], omeprazole, 5-OH omeprazole [41], loratadine (LOR), descarboethoxy-LOR [42], hydromorphone [43], levosulpiride [44], levofloxacin [45], carvedilol [46], and muraglitazar [47] in biological fluids where the analytes were extracted into an organic solvent by vortex-mixing and the organic layer was evaporated to dryness under nitrogen and then reconstituted. By LLE, the analytes are extracted through the partitioning between the aqueous and organic layers and the organic extracts need to be transferred for solvent evaporation and reconstitution.…”