Capillary ion analysis of lithium concentrations in biological fluids and tissues of Poecilia (teleost)

Capillary ion analysis (CLA) is a form. of capillary electrophoresis that u ses the differential electrophoretic mobility of ions to perform a separati on of an ionic mixture. Application of this technique for detection of lith ium concentrations in plasma and tissues of Poecilia was the purpose of thi s investigation. CIA was performed using a 75 mu m ID x 60 cm length fused- silica capillary and a run electrolyte of 67.7 mg hydroxyisobutyric acid (H IBA), 52.8 mg 18-crown-6-ether and 64 mu L UV-CAT-1 reagent (4-methylbenzyl amine) in a volume of 100 mL water (18 M Omega) with a voltage of 20 kV usi ng ultraviolet absorption detection at 214 nm. Migration times were: potass ium, 2.98 min; calcium, 3.48 min; sodium, 3.60 min; barium (internal standa rd), 4.15 min and lithium, 4.26 min. Lithium and barium migration times wer e stable and reproducible. Correlation coefficients (r) between peak area r atios of lithium/barium for concentrations ranging from 0.1 to 2.0 mM were from 0.976 to 0.996. Coefficients of variation (CV) for lithium concentrati ons ranged from 4.07 to 15.71% between days and 4.38 to 7.76% within-day. A pplication of this methodology for determination of lithium concentrations in the plasma, brains and livers of fish dosed with lithium for 23 days are presented. CLA is applicable to analysis of lithium concentrations in biol ogical fluids and tissues of fish.