Gingival matrix collagen in chronic periodontitis.

The isolation and characterization of cyanogen bromide peptides derived from the human gingival collagen of patients with chronic periodontitis revealed the presence of both Type I and Type III collagens in this tissue. The amount of TYPE III collagen, however, was found to be lower than that in normal gingival tissue. In addition, a non-collagenous protein fraction, accounting for approximately 20% of the insoluble matrix, was relatively rich in acidic, hydrophobic, and hydroxy-containing amino acids.

Determination of paracetamol and its metabolites in urine by high-performance liquid chromatography using ion-pair systems.

Paracetamol (P) and its four main metabolites, the sulphate (S), glucuronide (G), cysteine (C) and mercapturic acid (M) conjugates, are separated on ODS/TMS silica using a standard eluent, water-methanol-formic acid (86:14:0.1, v/v/v), in the order S, G, P, C, M. On addition of the ion-paring cations dioctylammonium (DOA) and tetrabutylammonium (TBA), the retention of S is vastly increased while those of G and M are substantially increased and that is C is reduced.

Determination of paracetamol and its metabolites in urine by high-performance liquid chromatography using reversed-phase bonded supports.

Paracetamol and its four main metabolites, the sulphate (S), glucuronide (G), cysteine (C) and mercapturic acid (M) conjugates, are readily separated in a synthetic mixture using slightly acidic aqueous alcoholic eluents (e.g. water-methanol-formic acid, 85:15:0.

Separation of catecholamines and their metabolites by adsorption, ion-pair and soap chromatography.

The separation of catecholamines and their metabolites has been carried out by high-performance liquid chromatography using three systems: liquid-solid adsorption, ion-pair partition, and soap chromatography. In the last newly developed technique a reversed-phase packing is used in conjunction with an aqueous organic eluent containing a detergent. The detergent is chosen so that its ion can form ion-pairs with ions of the solutes.

Separation of tetracyclines by high-speed liquid chromatography.

The separation of tetracycline and its four commoninpurities has been studied by high-speed liquid chromatography. A preliminary study of the effectiveness of ion-exchange, adsorption, liquid-liquid partition and reversed-phase ion-pair chromatography indicated that only the last method showed promise. By developing special hydrocarbon-bonded stationary phases a rapid and complete resolution of all five tetracyclines has been obtained within 10 min.