This Technical Overview demonstrates and discusses the influence of the injection parameters Feed Speed and Overfeed Volume on chromatographic separation. These parameters were introduced with the Agilent 1260 Infinity II Supercritical Fluid Chromatography (SFC) Multisampler. The influence on the isocratic separation of closely eluting compounds, shown for different injection volumes commonly u...

Phenylalanine, tyrosine, and tryptophan are isolated and quantified by "high-pressure" liquid chromatography, with fluorescence detection. An isocratic mobile phase and reversed-phase column are used to provide rapid and reproducible measurement of these amino acids in as little as 1 to 2 microL of human plasma.

A new flow-dependent separation selectivity (FDSS) effect was discovered in isocratic HPLC. Significant changes in chromatographic selectivity were achieved by simple variation of the mobile phase flow rate. The FDSS effect was observed for a core-shell stationary phase using silica particles as a core and a Zr-based metal-organic framework (UiO-66) as a shell.

Several extraction steps involved while analyzing metformin in plasma necessitates the need to develop a simple less tedious RP-HPLC method for analysis human saliva.Blank saliva (2 mL) was spiked with 2 mL solution (12.5 µg mL-1) of and 1 (0.5 caffeine as internal standard (IS). The mixture vortex mixed centrifuged at 3000 rpm 10 minutes. A portion resultant injected into HPLC machine (Agilent...

With so many options for method parameters to adjust during development, identifying a starting point can be intimidating. Starting with scouting gradients simplify the process, and yield rich results that inform subsequent development steps. In this installment, we discuss how design gradients, use resulting data make decisions about next steps (including whether isocratic or gradient elution)...