Many fast UHPLC and traditional HPLC methods suffer under delays caused by the need to wash and equilibrate the column after the separation. Typically we see 20%–40% of the runtime used up by these essential steps within a gradient method. Here a solution utilizing a dual-gradient pump setup with column switching capabilities to overcome these delays without the need of redeveloping existing methods is offered. The Thermo Scientific™ Dionex™ UltiMate™ 3000 LC Dual System with the Viper Tandem Operation kit allows to sppeding up gradients in LC and UHPLC assays.

Chromatographic separation is required for simultaneous analysis of 25-hydroxyvitamin D3 (25OHD3) and its epimeric form 3-epi-25-hydroxyvitamin D3 (epi-25OHD3) in a liquid chromatography-mass spectrometry (LC-MS) method because both compounds have the same molecular formulas and the same fragmentation spectra. We developed an LC method that provides baseline separation between the two isobaric compounds. We coupled this chromatographic method to an MS method, which collects high-resolution MS/MS spectra for compound identification and quantitation.

This Technical Note describes the use of high-surface-area solid phase extraction (SPE) to extract seven human hormones from drinking water using the Dionex AutoTrace 280 SPE instrument. Extracts were subsequently quantified using high-performance liquid chromatography (HPLC) to determine the recovery.

Cyanobacteria, commonly referred to as blue-green algae, are photosynthetic prokaryotes that occur naturally in surface waters. They contribute significantly to primary production and nutrient cycling. Blooms of toxic cyanobacteria species in surface drinking water sources and recreational waters threaten human health. Gastrointestinal illness, skin irritation, and death following renal dialysis have been attributed to acute cyanotoxin exposure. We describe a simple and sensitive LC-MS method for definitive identification and quantitation of microcystins in water.

The Thermo Scientific Dionex UltiMate 3000 system is applied for the analysis of nicotinic acid and thiocyanate. The separation was performed on a Thermo Scientific Acclaim Mixed-Mode WAX-1 column, with UV detection at 210 nm.