Vg. Rodriguez et al., SIMULTANEOUS DETERMINATION OF COBALT AND NICKEL BY REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH DIETHYLDITHIOCARBAMIC ACID, Journal of chromatography, 673(2), 1994, pp. 291-294
The reagent diethyldithiocarbamic acid has been examined for the high-
performance liquid chromatographic separation of cobalt(II) and nickel
(II) chelates on reversed-phase HPLC columns (150 x 3.9 mm) packed wit
h Nova-Pak C-18, 4 mu m. The metal-diethyldithiocarbamic chelates were
preconcentrated by solvent extraction. An aliquot of sample containin
g copper, cobalt and nickel in a mixture was transferred to a well-sto
ppered test tube to which was added reagent [diethyldithiocarbamic aci
d 0.5% in ethanol-water (1:1), pH 10] and 10 ml organic solvent (dieth
yl ether). After shaking with mechanical shaker for 5 min, the organic
layer was separated and 0.1 ml transferred to another tube containing
methanol (1 ml). The methanolic solution (15 mu l) was injected, on t
he reversed-phase HPLC column. The complexes are eluted with methanol-
water (75:25) at a flow-rate of 0.5 ml min(-1). The detection is carri
ed out with a UV detector at 260 nm. The method shows several advantag
es: short analysis time, minimized sample preparation, minimized effec
t of interfering ions, a low detection limit (50 ppb for nickel and 5
ppb for cobalt) and good reproducibility, making it suitable for many
types of samples, including alloys.