Background:We evaluated a new, automated multicapillary zone electrophoresis (CE) instrument (Capillarys ® , 4.51 software version; Sebia) for human serum protein analysis. Methods: With the Capillarys ␤1-␤2؉® reagent set, proteins were separated at 7 kV for 4 min in 15.5 cm ؋ 25 m fused-silica capillaries (n ‫؍‬ 8) at 35.5°C in a pH 10 buffer with online detection at 200 nm. Serum samples with different electrophoretic patterns (n ‫؍‬ 265) or potential interference (n ‫؍‬ 69) were analyzed and compared with agarose gel electrophoresis (AGE; Hydrasys ® -Hyrys ® , Hydragel protein(e) 15/30 ® reagent set; Sebia). Results: CVs were <3.5% for albumin, <11% for ␣ 1 -globulin, <4.1% for ␣ 2 -globulin, <7.4% for ␤-globulin, and <5.8% for ␥-globulin (3 control levels); measured throughput was 60 samples/h. In patients without paraprotein (n ‫؍‬ 116), the median differences between CE and AGE were ؊5.4 g/L for albumin, 4.0 g/L for ␣ 1 -globulin, 0.7 g/L for ␣ 2 -globulin, 0.6 g/L for ␤-globulin (P <0.001 for all fractions), and ؊0.1 g/L for ␥-globulin (not significant). More samples had at least one ␥-migrating peak detected by CE (n ‫؍‬ 135 vs 130; paraprotein detection limit, ϳ0.5-0.7 g/L), but fewer were quantified (n ‫؍‬ 84 vs 91) because of ␥-to ␤-migration shifts. There was a 1.2 g/L median difference between CE and AGE for ␥-migrating paraprotein quantification (n ‫؍‬ 69; P <0.001). Several ultraviolet-absorbing substances (lipid

We here describe an ion-exchange high-performance liquid chromatography technique with electrochemical detection for rapid quantification of glutathione, homocysteine, cysteinylglycine, and methionine. The analytical validation of the technique showed within-assay and between-assay coefficients of variation between 3.1 and 4.3%, and 3.7 and 8.6%, respectively. Percentages of recovery for overload and dilution tests were between 87 and 120%. Detection limits were 1 micromol/L for methionine and 0.5 micromol/L for other compounds. There was no interference with any physiological and pharmacological substances possessing a thiol function. Aminothiol concentrations determined in 100 control subjects (50 women and 50 men) showed no age- or sex-rated differences for except for homocysteine which was increased (+ 28%) in oldest subjects of both sexes. In 60 patients at risk (30 with chronic renal failure, 30 with diabetes), homocysteine concentration was significantly increased. No variation in other aminothiols was observed in diabetic subjects. Methionine was decreased and cysteinylglycine was increased in patients with chronic renal failure. The present technique-rapid, easy to use, and reliable-appears suitable for routine application in the exploration of aminothiol metabolic pathways including mechanisms of hyperhomocysteinemia.

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