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J L Glajch

Publications and source records attributed to J L Glajch.

5 recordsLinked to original sources

Effect of column degradation on the reversed-phase high-performance liquid chromatographic separation of peptides and proteins.

Many reversed-phase separations of proteins and peptides are currently performed in acidic mobile phases, e.g., 0.1% trifluoroacteic acid in water (pH 2) with organic modifiers. Such conditions are known to promote the cleavage of the silane from the silica in bonded-phase columns, especially for monomeric stationary phases. The stability of some columns commonly used for proteins and peptides has been examined, and it has been shown by both chromatographic and elemental analysis that degradation occurs very rapidly with fresh, "totally covered" column materials. Despite the loss of over half of the bonded phase in some cases, certain columns still exhibit adequate chromatographic performance, although reproducibility can be affected. The implications of these results with respect to both bonded-phase synthesis and mechanistic interpretation of chromatographic data is discussed.

Chromatography, High Pressure Liquid↗

Separation of proteins on a polymeric fluorocarbon high-performance liquid chromatography column packing.

A rigid, inert fluorocarbon resin has been evaluated as an high-performance liquid chromatography packing for the separation of proteins and peptides. Samples are separated with gradient elution of the mobile phase from aqueous buffer to acetonitrile. The selectivity and retention of the fluorocarbon resin packing for proteins are similar to that of aliphatic hydrocarbon-bonded silica packings.

Animals↗

Pyrolysis gas chromatography of enzymes.

Pyrolysis gas chromatography (PGC) has been shown to be useful for differentiating enzymes. The enzymes alpha-chymotrypsin, lactate dehydrogenase, catalase, and urease were easily "fingerprinted" on a 1.8 m 0.5% Carbowax 20 M column. Also, in some cases, isoenzymes of lactate dehydrogenase could be distinguished. Based on the pyrolyses of the free aromatic amino acids, four major enzyme pyrolysis peaks were tentatively identified as organic compounds derived from tyrosine and tryptophan. The use of a nitrogen-selective detector in conjunction with the FID and measurement of peak retention times by computer on three different types of columns permitted confirmations of peak identity.

Acetylcholinesterase↗