strong sulfuric acid solutions, and can be measured by a fluorometer.1) Gotelli et al.2) and Shihabi et al.3) have used high-performance liquid chromatography (HPLC) to separate fluorescent derivatives, and have measured cortisol levels in serum and urine. Since the sulfuric acid-induced fluorescence is unstable, it is necessary to inject the reaction mixture into HPLC immediately after the for...

The triacylglyceride components of cottonseed oil were isolated and positively identified by a combination of high performance liquid chromatography (HPLC) and gas chromatography (GC). Both reversed-phase HPLC and capillary GC were capable of separating the oil into triacylglyceride peaks. These peaks were isolated by HPLC and their component acyl groups were converted to fatty acid methyl este...

In China, traditional Chinese medicines (TCMs) have been used in clinical applications for thousands of years. The successful hyphenation of high-Performance liquid chromatography (HPLC) and mass spectrometry (MS) has been applied widely in TCMs and biological samples analysis. Undoubtedly, HPLC/MS technique has facilitated the understanding of the treatment mechanism of TCMs. We reviewed more ...

A novel fast high-performance liquid chromatography (HPLC) method coupled with diode array detection (DAD) and time-of-flight mass spectrometry (TOF/MS) was developed for qualitative and quantitative analysis of Radix Astragali products. The potential of fast HPLC on 1.8-microm particles was compared with the performance of HPLC on conventional 5-microm particles columns. Significant advantages...

Technical improvements have been applied to reduce the time required for the determination of calcidiol and calcitriol in serum or plasma. The modifications include the use of Sep-Pak C18 cartridges for the extraction of calciol metabolites from serum instead of a classical liquid/liquid extraction, a considerable shortening of the HPLC purification time compared with our previously described m...

This work proposes a procedure to estimate the measurement uncertainty for the quantification of cefazolin by high-performance liquid chromatography (HPLC) and microbiological assay (bioassay). HPLC method was performed according to United States Pharmacopeia (USP) and bioassay according to Brazilian Pharmacopeia (FB). The quantification of cefazolin by high-performance liquid chromatography wa...

In this article, we describe a fast and specific method to measure 5FU with HPLC tandem-mass spectrometry. Reversed-phase HPLC was combined with electrospray ionization tandem mass spectrometry and detection was performed by multiple-reaction monitoring. Stable-isotope-labeled 5FU (1,3-15N2-5FU) was used as an internal standard. 5FU was measured within a single analytical run of 16 min with a l...

An analytical methodology was developed to quantitate the intracellular nucleotides including mono-, di-, and triphosphates and the diphosphocholine derivative of (-)-2', 3'-deoxy-3'-thiacytidine (3TC) in human peripheral blood mononuclear cells (PBMCs). The procedure includes the resolution of 3TC nucleotides by solid-phase extraction (SPE) on an anion-exchange cartridge, with subsequent enzym...

BACKGROUND Although high-performance liquid chromatography (HPLC) is the commonly used method for the analysis of retinol in biological samples, simple and rapid test kits are available. OBJECTIVES This study compared a rapid test kit (ICHECK Fluoro®) to HPLC for the assessment of serum retinol concentrations. METHODS For the analysis by HPLC, sample preparation included standard deproteini...

The HPLC/MS system, in which a monolithic silica capillary column is directly connected to an electronspray-ionization mass spectrometer, showed superior performance at high mobile phase linear velocity. A two-dimensional (2D) HPLC/MS system was established, using an ion-exchange particle-packed capillary column at the first dimension and a monolithic silica capillary column at the second dimen...