Combined Protein and Alkaloid Research of Latex Reveals CmMLP1 Accompanied by Alkaloids with Cytotoxic Potential to Human Cervical Carcinoma Cells.

L. is a latex-bearing plant used in traditional folk medicine to treat human papillomavirus (HPV)-caused warts, papillae, and condylomas. Its latex and extracts are rich in many low-molecular compounds and proteins, but there is little or no information on their potential interaction.

Is a deuterated internal standard appropriate for the reliable determination of olmesartan in human plasma?

A right choice of the internal standard is one of the most challenging tasks during bioanalytical method development. Surprisingly, among the HPLC-MS methods for the determination of a cardiovascular drug olmesartan in plasma only structural analogues or similar compounds were used as internal standards. We have tried to answer the question whether the stable isotope labelled (deuterated) internal standard, as recommended by regulatory agencies, can be used for the reliable determination of olmesartan in human plasma.

Sensitive single quadrupole LC/MS method for determination of lapatinib in human plasma.

A sensitive liquid chromatographic-single quadrupole mass spectrometric method was developed and validated for the determination of lapatinib in human plasma. Following a liquid-liquid extraction with methyl t-butyl ether, lapatinib and isotope labelled lapatinib, used as an internal standard (IS), were separated from the endogenous compounds on a Zorbax SB-C18 (150 x 3 mm, 3.5 μm) column.

Determination of sunitinib in human plasma using liquid chromatography coupled with mass spectrometry.

An original method based on liquid chromatography with single quadrupole electrospray ionization mass spectrometry was developed for the determination of sunitinib in human plasma. The quantitation limit of the method at 0.10 ng/mL is comparable to that of tandem mass spectrometry assays.

Determination of fluoride as fluorosilane derivative using reversed-phase HPLC with UV detection for determination of total organic fluorine.

A quantitative method for fluoride determination using RP HPLC and UV detection was developed. The method is based on the reaction of fluoride with triphenylhydroxysilane in highly acidic conditions and extraction of the reaction product into n-heptane. Chromatographic conditions as well as the derivatization parameters were optimized.

Preconcentration and decomposition of perfluorinated carboxylic acids on an activated charcoal cartridge with sodium biphenyl reagent and its determination at microg L(-1) level on the basis of flow injection-fluorimetric detection of fluoride ion.

Perfluorinated surfactants of heptafluorobutylate and pentadecafluorooctanoate ions were adsorbed on an activated charcoal cartridge and decomposed with sodium biphenyl (SBP) reagent to form inorganic fluoride ion. The fluoride ion thus formed was determined by flow injection analysis (FIA) using quercetin-Zr complex as a fluorimetric reagent, where lambda(ex) and lambda(em) were 422 and 491 nm, respectively. The limit of detection for fluoride ion by the FIA system was developed to 1.

Flow-injection determination of total organic fluorine with off-line defluorination reaction on a solid sorbent bed.

Considering recent reports on widespread occurrence and concerns about perfluoroalkyl substances (PFAS) in environmental and biological systems, analysis of these compounds have gained much attention in recent years. Majority of analyte-specific methods are based on a LC/MS/MS or a GC/MS detection, however many environmental or biological studies would benefit from a total organic fluorine (TOF) determination. Presented work was aimed at developing a method for TOF determination.

On-line preconcentration techniques in determination of melatonin and its precursors/metabolites using micellar electrokinetic chromatography.

Determination of melatonin (MT) (N-acetyl-5-methoxytryptamine) and related indole compounds using standard capillary electrophoresis (CE) system with UV detection was investigated. Satisfactory separations of six analytes i.e.