Hydrophilic interaction chromatography with Fourier transform mass spectrometry of monosaccharide anhydrides.

A fast, selective, and sensitive method for the determination of three monosaccharide anhydrides (galactosan, mannosan, levoglucosan), based on hydrophilic interaction chromatography and Fourier transform mass spectrometry, was successfully developed. The simple experimental stationary phase and mass spectrometry performance screening allowed the selection of the best available chromatographic and mass spectrometry conditions. Thus, the chromatographic separation was performed on a highly selective stationary phase containing a zwitterionic phosphorylcholine group and the monosaccharide anhydrides were detected as [M+HCOO] adduct in the negative mode.

Online molecularly imprinted solid-phase extraction coupled to liquid chromatography-tandem mass spectrometry for the determination of hormones in water and sediment samples.

The molecularly imprinted SPE directly coupled to RP LC-MS/MS method has been developed and successfully validated for the determination of six hormones in water and sediment samples. The method is based on the use the home-made column filled with a molecularly imprinted sorbent (imprinted against estrogens) that was used under nonaqueous conditions. Thus, its high selectivity could be utilized resulting in low matrix components' coextraction.

The use of molecularly imprinted polymers for the multicomponent determination of endocrine-disrupting compounds in water and sediment.

The method employing molecularly imprinted polymers for the extraction and clean up of endocrine-disrupting compounds (estrogens, bisphenol A, and alkylphenols) from water and sediment is described. The identical extraction/clean-up and LC-MS/MS condition were used for the analysis of both types of samples. The method showed high recoveries ranging from 90 to 99% with excellent precision (intrabatch: 3.

Multi heart-cutting two-dimensional liquid chromatography-atmospheric pressure photoionization-tandem mass spectrometry method for the determination of endocrine disrupting compounds in water.

The multi-heart-cutting two-dimensional liquid chromatography-tandem mass spectrometry method using atmospheric pressure photoionization has been developed and successfully validated for the determination of nine endocrine disrupting compounds in river water. The method is based on the use of two different reverse-phase columns connected through a six-port two-position switching valve equipped with a 200 μl loop. An orthogonal separation was achieved by proper selection of stationary phases, mobile phases, and the use of a gradient elution in both dimensions.

On-line two-dimensional liquid chromatography-tandem mass spectrometric determination of estrogens in sediments.

The development of an on-line system for the simultaneous determination of α-estradiol, β-estradiol, estrone and 17α-ethynylestradiol in river sediments is described. The analytes were extracted from sediments by microwave-assisted extraction. A crude extract was directly analysed by a heart-cutting two dimensional high-performance liquid chromatography-ion trap-tandem mass spectrometry with an atmospheric pressure photoionization source operating in the positive mode.

Enhancing sensitivity of liquid chromatographic/ion-trap tandem mass spectrometric determination of estrogens by on-line pre-column derivatization.

A rapid and sensitive liquid chromatographic/ion-trap mass spectrometric method has been developed for the simultaneous determination of estriol, alpha-, beta-estradiol, 17alpha-ethynylestradiol and estrone. The substances were extracted from river water samples (typically 250 ml) and cleaned-up using two-stage solid-phase extraction (SPE). 12-(Difluoro-1,3,5-triazinyl)-benz[f]isoindolo-[1,2b][1,3]benzothiazolidine was applied as a derivatizing agent.

Combined isolation and purification procedures prior to the high-performance liquid chromatographic-ion-trap tandem mass spectrometric determination of estrogens and their conjugates in river sediments.

A fast and sensitive analytical procedure has been developed for the simultaneous separation and determination of alpha-estradiol, beta-estradiol, estriol, estrone and ethynylestradiol and their sulfate, glucuronide and acetate conjugates in river sediments. The procedure includes a microwave-assisted extraction (MAE) with aqueous methanol (25:75, v/v) at 100 degrees C in 10 min, a clean-up on Oasis WAX cartridge and a high-performance liquid chromatography-ion-trap tandem mass spectrometry (HPLC-IT-MS/MS) with electrospray ionization. The recovery for each compounds ranged from 83 to 107% and the repeatability represented as RSDs ranged from 4.

High-performance liquid chromatographic/ion-trap mass spectrometric speciation of aquatic mercury as its pyrrolidinedithiocarbamate complexes.

Mercury-pyrrolidinedithiocarbamate complexes are first time used for speciation of aquatic mercury with high-performance liquid chromatographic/ion trap-mass spectrometric method utilizing atmospheric pressure chemical ionization (APCI). The separation of the four mercury species was achieved in less than 5 min with a linear gradient profile of aqueous methanol from 70 up to 100% (v/v) in 4th min, isocratic elution at 100% up to 5th min and followed by a negative gradient to 70% in 6th min. The best separation was achieved on a reverse phase Zorbax Eclipse XDB C18 column (50 mm x 2.

High performance liquid chromatography/ion-trap mass spectrometry for separation and simultaneous determination of ethynylestradiol, gestodene, levonorgestrel, cyproterone acetate and desogestrel.

A fast and highly sensitive high performance liquid chromatographic/ion-trap mass spectrometric method (LC/MS) has been developed for simultaneous determination of ethynylestradiol (EE2), gestodene (GES), levonorgestrel (LNG), cyproterone acetate (CPA) and desogestrel (DES). Among three types of sorbents tested (C8, C18 and phenyl) from two suppliers, the best separation was achieved on reverse phase Zorbax SB-Phenyl column using aqueous methanol as a mobile phase. A linear gradient profile from 70 up to 100% (v/v) in 7th min, kept constant at 100% up to 10th min and followed by a negative gradient to 70% of methanol up to 12th min was used for elution.

Liquid chromatographic--cold vapour atomic fluorescence spectrometric determination of mercury species.

Solvent extraction, sonication, and microwave-assisted extractions in the presence of extraction agents (thioacetic acid, citric acid, cysteine, 2-mercaptoethanol, HCl + NaCl, etc.) were tested for the isolation of mercury species. A mixture of 6 M HCl and 0.

Determination of available phenolic compounds in soils by liquid chromatography with solid-phase extraction.

A fast, selective, and sensitive liquid chromatographic (LC) method was developed for determination of derivatives of benzoic and cinnamic acids (gallic, protocatechuic, 2,3,4-trihydroxybenzoic, 4-hydroxybenzoic, vanillic, caffeic, syringic, 4-coumaric, ferulic, sinapic, benzoic, 2-coumaric, cinnamic acids, and 4-hydroxybenzaldehyde and vanillin) in soil samples. The method for sample pretreatment is based on temperature-controlled extraction with water (pH 5.6) for 60 min.