A novel automated multi-cycle magnetic solid-phase extraction coupled to LC-MS/MS to study the disorders of six functional B vitamins in patients with gastroenterology and hyperhomocysteinemia.

B vitamins are essential for human life and their disorders can cause a variety of diseases. Solid-phase extraction (SPE) coupled to LC-MS/MS is a preferred technique for determining multiple B vitamins, however, their complexity in real biological matrices makes it hard to achieve satisfactory recovery and accuracy when simultaneous detection. In this study, a novel automated multi-cycle magnetic SPE (MSPE) coupled to the LC-MS/MS method was established using a mixed-mode anion exchange magnetic adsorbent for the simultaneous extraction of six functional B vitamins, including methylmalonic acid, riboflavin, pantothenic acid, 4-pyridoxic acid, folic acid, and 5-methyltetrahydrofolate.

Simple and fast determination of tetrodotoxin in human plasma based on hydrophilic-interaction/ion-exchange mixed-mode solid phase extraction combined with liquid chromatography-tandem mass spectroscopy.

In this study, we developed and validated a simple, fast and sensitive LC-MS/MS method for the measurement of tetrodotoxin (TTX) in human plasma. Three HILIC-type solid phase extraction (SPE) carriers (PSA, silica, Siphila i HILIX) with different stationary phase functional groups were compared. The Siphila i HILIX SPE plate containing multi-carboxyl groups was finally selected due to obviously better extraction recovery of TTX (about 80% of recovery from plasma samples) than the other two and no significant matrix effects were observed, which was speculated to have mixed-mode synergistic effects of hydrophilic interaction and ion exchange.

Development and validation of a ligand-binding assay for quantification of the F(ab') antivenom of Daboia russelii siamensis in human serum and its application to a phase I clinical study.

Daboia russelii siamensis accounts for most of snakebite mortalities in China, yet, specific treatment against the venom toxins is absent in clinical practice. The F(ab') antivenom of Daboia russelii siamensis is manufactured and approved for the clinical trial in China. To satisfy the need for clinical pharmacokinetic research, this study aimed to develop a ligand binding assay (LBA) for the quantification of F(ab') antivenom of Daboia russelii siamensis in human serum.

Liquid chromatography-tandem mass spectrometric assay for TPN171 in human plasma.

A simple, rapid and accurate method for quantitative analysis of a highly selective phosphodiesterase-5 inhibitor (PDE5), TPN171 by high performance liquid chromatography and tandem mass spectrometry in human plasma was proposed and validated successfully using D-TPN171 as internal standards (ISTD). An aliquot of 100 μL of plasma was mixed with internal standard and was precipitated with acetonitrile. Gradient elution was performed on a ACQUITY HSS T3 column (50 × 2.