Flow-injection extraction spectrophotometric determination of nickel using naphthazarin reagent.

Abstract

ABSTRACT            Attempts had been made to determine of nickel by using Naphthazarin (Naph) for the extraction and spectrophotometric method both manually and flow injection system. This was the first use of Naphthazarin (Naph) for the extraction and determination of nickel in the extracted samples. This method was successfully applied to detect nickel in nickel-based alloys, pig feeds or electroplanting solutions.            Two procedures had been developed for the determination of nickel, manual spectrophotometry and flow injection spectrophotometry. Nickel could be determined spectrophotometrically at 370 nm after extraction of the chelate into chloroform in the first procedure. The calibration graph was linear up to 50 mg per ml of nickel at 370 nm. The relative standard deviation for the determination of 50 mg per ml of nickel was 1.40 % (n=10). Nickel could be determined by flow injection spectrophotometry at 370 nm after extraction of the chelate into chloroform. The carrier stream was deionized water and the reagent streams were acetate buffer (pH 5) and 0.226 % (w/v) Naph solution. The sampling rate was 30 per h. The calibration graph was linear up to 100 mg per ml of nickel. The percent relative standard deviation was 1.75% (n=10) for 20 mg per ml of nickel. It was found that the reagents used in this work were most suitable for the flow injection systems. The system was successfully applied to determine nickel existing in nickel-based alloys and pig feeds.