Search

A solvent sublation-spectrophotometric method lor the determination of nickel(II) is proposed. Solvent sublation is used here to concentrate trace nickel(II) using 1-(2-pyridylazo)-2-naphthol (PAN) as a collector. At pH 3 to 11 a red complex of nickel(II) formed with PAN can be floated with the aid of small nitrogen bubbles, then dissolved in benzene. The main factors affecting the solvent sublation of nickel(II) were determined by an orthogonal experimental method. This method permits the determination of nickel(II) in the range 0- 1 jag/ml and can be applied to samples of drinking water with good results.

A rapid and accurate method for the direct simultaneous determination of nitrate and nitrite is proposed. The method is applied to the determination of nitrate and nitrite in rainwater and wastewater without preliminary separation. The determinations are performed by a CPA matrix method with ultraviolet spectrophotometric detection. The results obtained are in agreement with those obtained by conventional methods for the determination of nitrate and nitrite.

A sensitive and precise method for the determination of microgram amounts of zinc (II) has been developed. The ion associate of the anionic zinc (II)-thiocyanate complex with malachite green (MG) can be floated with the aid of small nitrogen bubbles, then dissolved in toluene. The formation of the ion associate takes place over a wide pH range (3-7). The method permits the determination of zinc (II) in the range 0–1.1 jig/ml and can be applied to samples of drinking water with good results.