Sintered thin-layer chromatography

Monolithic Porous Polymer Layer for the Separation of Peptides and Proteins Using Thin-Layer Chromatography Coupled with MALDI-TOF-MS

Plates for thin-layer chromatography (TLC) with an attached layer of porous polymer monolith have been prepared and used for the separation of small molecules, peptides, and proteins. The 50-200-mum. thin poly(butyl methacrylate-co-ethylene dimethacrylate) layers were prepared in situ using UV-initiated polymerization. Precise control of the reaction conditions enables the preparation of monolithic layers with a well-defined porous structure that determines the chromatographic performance. Compared to conventional TLC and high-performance TLC using precoated layers based on silica, the small layer thickness and absence of any binder is expected to improve both retention characteristics and separation efficiency of the polymer-based monolithic thin-layer chromatographic plates. Spots of the separated compounds were first detected using typical UV imaging. Since the monolithic thin layers can be also prepared directly on the stainless steel MALDI carrier plate, the separation in TLC format can be coupled with MALDI-TOF-MS. Application of a conventional MALDI matrix facilitated desorption and ionization of peptides and proteins for molecular weight determination of the separated compounds.

Progress in densitometry for quantitation in planar chromatography

The principal methods for obtaining quantitative information from separations performed by planar chromatographic techniques are reviewed. Recent advances in obtaining structural information for sample identification of separated components are also discussed. Reasonable expectations concerning future developments in densitometry are made.

Evaluation of paraquat concentrations in paraquat poisoning

The toxicological significance of paraquat concentrations in paraquat poisonings was evaluated by means of multivariate analysis methods. Paraquat could be determined by a newly developed procedure, which involved thin-layer chromatography with flame ionization detector (TLC-FID) and solid-phase extraction with a disposable octadecylsilane cartridge. This new method proved to be simple, rapid and reliable for the analysis of paraquat in our seven cases of suicidal poisoning. The relationship between plasma paraquat concentration (C) and time from ingestion (T) could be best described by the following functions. The regression equation of fatal cases was ln[ln(C X 1000)] = 2.5453 - 0.2114 lnT. The regression equation of survivors was ln[ln(C X 1000)] = 2.1041 - 0.2826 lnT. The discriminant function (D) to separate the fatal and survival cases was D = 1.3114 - 0.1617 lnT - 0.5408 [ln(C X 1000)] (fatal cases: D less than 0, survivors: D greater than 0). The discriminant function was demonstrated to have a high reliability for the toxicological significance in our seven poisoned patients. The significant correlation between plasma paraquat concentration and urine paraquat concentration (C') in our cases was obtained. The regression equation was lnC' = 0.953 lnC + 1.409. This also indicated that urinary concentrations are 3.3 - 4.5 times greater than plasma concentrations. The multiple regression equation among plasma paraquat concentration, time from ingestion, and the ingested volume (V) of Gramoxone (trade name of paraquat), was lnC = 0.009V - 0.232T + 3.612. It is suggested that the determination of paraquat is of great value, and that these data are useful in assessing the severity and predicting the outcome of poisoning for forensic and clinical purposes.