Multidimensional high-performance liquid chromatography on Pinkerton ISRP and RP18 columns: direct serum injection to quantify creatinine.
A two-dimensional high-performance liquid chromatographic method for the determination of creatinine with direct serum injection without sample pretreatment has been developed. The column-switching technique allowed a switch from columns packed with internal surface reversed-phase (ISRP) material to columns of almost any other material, even if the eluents necessary in a particular case do not appear to be directly compatible. A Pinkerton ISRP column, which stands out because of its very good stability when loaded with undiluted serum samples, was used as precolumn. The creatinine-containing fraction was switched to a reversed-phase Shandon RP18 column and was focused there by alteration of the eluent from pH 6.5 to phosphoric acid-ion-pair reagent. The separation occurs via a pH gradient, with ultraviolet detection at 234 nm. This method stands out particularly for its good long-term stability, simple sample handling without pretreatment, high selectivity, a broad linearity (0.3-30 mg/dl creatinine), good reproducibility (inter-assay coefficient of variation less than 3%) and high recovery (97-100%) relative to values obtained with gas chromatography-mass spectrometry.
Puhlmann
A
A
Diagnostics Research Laboratory Systems, Boehringer Mannheim GmbH, Tutzing, Germany.
Dülffer
T
T
Kobold
U
U
D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D003404:Creatinine / Q000097:blood*; D006801:Humans; D012015:Reference Standards; D013056:Spectrophotometry, Ultraviolet
D003404:Creatinine