Spectrophotometric determination of cyanide by flow injection analysis

The flow injection technique is shown to provide fast, reliable, and sensitive determination of cyanide. Spectrophotometric detection in the ultraviolet region at 267 nm was used for measuring the absorbance of tetracyanonickelate (II) complex ion. The nickel carrier stream and the sample solutions were buffered at pH 10 (ammoniacal buffer). The method has a detection limit of 0.2 ppm cyanide. At a sampling rate of 90 samples per hour, with 60 ..mu..l sample injections, high reproducibility of measurements was achieved, with about 1% relative standard deviation. The effect of sample volume, flow rate, coil length, and anions interference on the FIA-spectrophotometric signals are reported.