Solid-phase spectrophotometric determination of nickel in water and vegetable samples at sub-mug l(-1) level with o-carboxylphenyldiazoaminoazobenzene loaded XAD-4.
A highly sensitive and selective solid-phase spectrophotometric method for the determination of sub-mugl(-1) level nickel(II) is described. Nickel(II) was sorbed on a styrene-divinylbenzene-type resin Amberlite XAD-4 as a Ni(II)-o-carboxylphenyldiazoaminoazobenzene (o-CDAA) complex. At pH 9.0, resin phase absorbances at 588 and 800nm were measured directly with an apparent molar absorptivity of 2.95x10(7)gmol(-1)cm(-1). The linear range of the determination was 1.2-41mugg(-1) resin. The detection limit and the quantification limit were found to be 0.24 and 0.76mugg(-1) resin, respectively. The relative standard deviation of 10 replicate determinations of 1.0mug nickel(II) in 100ml sample was of 1.5%. The tolerance limit of coexistent ions was also investigated. Most of them are in tolerable amount. For practical analyses, 1ml acetylacetone used can eliminate the interferences caused by Cu and Fe. The procedure was validated by analysis a certified water reference material (GBW 08618 Beijing, China) and a tomato leaf certified reference material (GBW 08402 Beijing, China) with the results in agreement with the certified values. The method was applied to the determination of nickel(II) in water and vegetable samples with satisfactory results.
Liu
Yongwen
Y
School of Chemistry and Chemical Engineering of Lanzhou University, Lanzhou 73000, China; Department of Chemistry, Institute of Datong, Yanbei Normal Institute, Shanxi Datong University, Datong 037000, China.
Chang
Xijun
X
Wang
Sui
S
Guo
Yong
Y
Din
Bingjun
B
Meng
Shuangming
S