Gas Chromatographic Method for the Analysis of Organic Acids in the Bio-Catalytic Conversion Process.

An analytical method for the quantification of acrylic acid (AA), 1,3-propanediol (1,3-PD) and 3-hydroxypropionic acid (3-HP) in the bio-catalytic conversion process has been developed by gas chromatography. A simple liquid-liquid extraction (LLE) procedure was used in the sample preparation. Organic acid additives such as trifluoroacetic acid were used to improve the extraction efficiency in the LLE procedure.

Gas chromatographic method for the determination of residual monomers, 2-(acryloyloxy)ethyl isocyanate and 2-(methacryloyloxy)ethyl isocyanate, as curing agents in an ultraviolet curable adhesive.

A gas chromatographic method is described for the determination of residual 2-(acryloyloxy)ethyl isocyanate (AOI) and 2-(methacryloyloxy)ethyl isocyanate (MOI) as curing agents in an ultraviolet curable adhesive. Pre-column derivatization was employed in the determination of AOI and MOI as a means of enhancing the response of the flame ionization detector. Urethane derivatives of AOI and MOI were derived using methanol for 30 min at room temperature.

Chiral recognition of N-phthaloyl, N-tetrachlorophthaloyl, and N-naphthaloyl α-amino acids and their esters on polysaccharide-derived chiral stationary phases.

Enantiomeric separations of N-phthaloyl (N-PHT), N-tetrachlorophthaloyl (N-TCPHT), and N-naphthaloyl (N-NPHT) α-amino acids and their esters were examined on several kinds of polysaccharide-derived chiral stationary phases (CSPs). Resolution capability of CSPs was greater Chiralcel OF than the others for N-PHT and N-NPHT α-amino acids and their esters. In N-TCPHT α-amino acids and their esters, good enantioselectivities showed Chiralcel OG for N-TCPHT α-amino acids, Chiralpak AD for N-TCPHT α-amino acid methyl esters, and Chiralcel OD for N-TCPHT α-amino acid ethyl esters, respectively.

High-performance liquid chromatographic method of photoactive compounds based on diazonaphthoquinone for positive photoresists.

An analytical method for the compositional and quantitative analysis of photoactive compounds (PACs) in positive photoresist (Posi PR) has been developed by high-performance liquid chromatography (HPLC). Under optimum HPLC conditions, various types of PACs consisting of a mixture of isomers were satisfactorily separated with no interference. This method was applied to the quantitative analysis of PACs in Posi PR.

LC-MS/MS method for the quantification of myo- and chiro-inositol as the urinary biomarkers of insulin resistance in human urine.

A simple LC-MS/MS method has been developed and validated for the quantification of endogenous myo- and chiro-inositol in human urine. myo- and chiro-Inositol were completely resolved from other carbohydrates and there were no interference peaks in human urine. The correlation coefficient (n = 3) was greater than 0.

Analysis of polymer additives in high-temperature liquid chromatography.

A high-temperature liquid chromatographic technique is employed for the separation of commercially available polymer additives to enhance the resolution and speed. Separation efficiencies and elution behaviors for seven phthalate plasticizers and five antioxidants are evaluated at elevated column temperatures and with a thermal gradient. Diamondbond C18 (octadecylsilica), Zirchrom PS (zirconia-based polystyrene), and Zirchrom PBD (zirconia-based polybutadiene) columns are selected for the study because of their thermal stability.

Liquid chromatographic enantiomer separation of racemic amine using chiral crown ether stationary phase.

Direct enantioseparation of racemic amine, amino-thiophene-2-yl-acetonitrile (TAN), on chiral crown ether stationary phase [Crownpak CR (+)] is described in this study. The elution behavior and the effect of acid additives on resolution of racemic amine, TAN, is intensely investigated. Moreover, the chiral recognition mechanism in this specific system is proposed based on computational methods with the density functional theory.

Enantiomer separation of a novel aminothiazolecarboxamide fungicide using polysaccharide-derived chiral stationary phases.

The direct enantioseparation of a novel aminothiazolecarboxamide fungicide, ethaboxam, on polysaccharide-derived chiral stationary phases (CSPs) is described. Good resolution is achieved with several polysaccharide-derived CSPs. Chiralcel OD (OD-H) and Chiralpak AS are excellent for direct enantiomer separation of ethaboxam.

Liquid chromatographic determination of novel aminithiazolecarboxamide fungicide residues in soil and crops using online solid-phase extraction.

A simple and convenient liquid chromatographic method has been developed and applied to the analysis of the novel aminothiazolecarboxamide fungicide, ethaboxam, in soil and crops. After the isolation and concentration of analyte from soil and crops, clean-up and separation of sample solutions are performed by high-performance liquid chromatography with online solid-phase extraction. Good linearity (r2 > 0.

Reversed-phase liquid chromatographic method for the analysis of aminoglycoside antibiotics using pre-column derivatization with phenylisocyanate.

A pre-column derivatization liquid chromatographic method has been developed for the analysis of aminoglycoside antibiotics using phenylisocyanate as a derivatization reagent. Derivatives including kanamycin, neomycin and gentamicin were formed by reaction of the analytes with phenylisocyanate in the presence of triethylamine. Phenylisocyanato groups were attached to corresponding amino groups of aminoglycoside and their molecular mass was confirmed by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS).

Determination of melagatran in rabbit plasma by high-performance liquid chromatography with automated column switching.

Melagatran is an active thrombin inhibitor showing oral and parenteral bioavailability for antithrombotic therapy. A simple and convenient liquid chromatographic method has been developed and applied to the analysis of melagatran in rabbit plasma. The clean-up and separation of the sample solutions were performed by automated on-line column switching HPLC.

Enantiomeric discrimination of pyrethroic acid esters on polysaccharide derived chiral stationary phases.

Enantiomeric separation of pyrethroic acid methyl and ethyl esters was examined on cellulose-based chiral stationary phases (CSPs): chiralcel OD (cellulose tris(3,5-dimethylphenyl carbamate)) and chiralcel OF (cellulose tris(4-chlorophenyl carbamate)). The good resolution of pyrethroic acid esters was achieved on chiralcel OD and OF. Separation factors ranged from 1.

Comparison of reversed-phase liquid chromatographic methods for the separation of new quinolones.

Reversed-phase high-performance liquid chromatography is widely used in the analysis of drug substances and their metabolites. The interaction of quinolones with residual silanol in a silica-based C18 stationary phase causes peak broadening and bad peak shapes and makes it hard to resolve the peak separations. This unusual interaction is studied and finally can be removed by masking the residual silanol of a silica-based C18 stationary phase, then good peak separation is achieved.