Micellar electrokinetic capillary chromatography determination of guanidino compounds in serum of uremic patients by using pyridoin as derivatizing reagent

An analytical procedure has been developed for the determination of 5 guanidino compounds; guanidine (g),guanidinoacetic acid (gaa),guanidinopropionic acid (gpa),guanidinobutyric acid (gba),and guanidinosuccinic acid (gsa) by micellar electrokinetic capillary chromatography (mekc) within 5 min. using pyridoin as derivatizing reagent. sodium dodecyl sulfate (sds) (0.03 m) was used as a micellar medium in sodium tetraborate (0.1 m) buffer at ph 9. uncoated fused silica capillary was used with effective length 39 cm and 75 μm id. applied voltage was 25.2 kv and photo diode array detection was at 228 nm. linear calibrations were obtained from 0.70 to 122 μmol/l and limits of detection (lods) were within 0.023-0.032 μmol/l. the derivatization and separation were repeatable with relative standard deviation (rsds) within 1.2-3.1 %. serum of healthy volunteers and uremic patients was analyzed and amounts found in uremic patients were g 1.71-2.64,gaa 4.56-6.61,gpa 1.15-1.94,gba 1.25-1.98,and gsa 6.81-8.56 μmol/l with rsd (n=4) within 1.2-3.3 %. the amount of guanidino compounds in uremic patients was found higher than healthy volunteers.