Determination of active vitamin B12 (cobalamin) in dietary supplements and ingredients by reversed-phase liquid chromatography: Single-laboratory validation.

Vitamin B12 dietary supplement can be critical to the alleviation strategies against micronutrient malnutrition and food insecurity. An HPLC-DAD method has been developed and validated, per AOAC SMPR 2016.017 (Standard Method Performance Requirements), for the quantitation of four bioactive forms of vitamin B12 (adenosylcobalamin, cyanocobalamin, hydroxocobalamin, methylcobalamin) from dietary ingredients and supplements.

Analysis of polynuclear aromatic hydrocarbons in olive oil after solid-phase extraction using a dual-layer sorbent cartridge followed by high-performance liquid chromatography with fluorescence detection.

A simple and easy direct solid-phase extraction (SPE) method was developed for the analysis of polynuclear aromatic hydrocarbons (PAHs) in olive oil using a dual-layer cartridge containing activated Florisil and a mixture of octadecyl (C18)-bonded and zirconia-coated silicas. Undiluted olive oil was applied directly to the SPE cartridge, and the sample was eluted with acetonitrile solvent. Background in the extract was found to be low enough for either gas chromatography-mass spectrometry (GC-MS) or high-performance liquid chromatography with fluorescence detection (HPLC-FLD) analysis.

In vitro evaluation of new biocompatible coatings for solid-phase microextraction: implications for drug analysis and in vivo sampling applications.

A new line of solid-phase microextraction (SPME) coatings suitable for use with liquid chromatography applications was recently developed to address the limitations of the currently available coatings. The proposed coatings were immobilized on the metal fiber core and consisted of a mixture of proprietary biocompatible binder and various types of coated silica (octadecyl, polar embedded and cyano) particles. The aim of this research was to perform in vitro assessment of these new SPME fibers in order to evaluate their suitability for drug analysis and in vivo SPME applications.

Evaluation of a solid-phase extraction dual-layer carbon/primary secondary amine for clean-up of fatty acid matrix components from food extracts in multiresidue pesticide analysis.

The use of dual-layer solid-phase extraction (SPE), a primary-secondary amine (PSA) in combination with graphitized carbon black (GCB), was evaluated for sample clean-up during multiresidue pesticide screening of agricultural and food products. The retention of fatty acids by the PSA sorbent was quantified and the effect of the elution solvent on the retention of fatty acid on the SPE cartridge was evaluated. The use of stronger elution solvents to elute certain pesticides from graphitized carbon was shown to interfere with the capacity of PSA to bind fatty acids.