A Selective Determination of Azide by Ion-Interaction Reversed-Phase HPLC

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Abstract
A method is presented for the analysis of sodium azide, based on the use of ion-interaction reversed-phase HPLC chromatography. A C-18 reversed-phase is the stationary phase and octylammonium ortho-phosphate at different pH values is the interaction reagent Spectrophotometric detection at 230 nm is employed. The analysis is free from interference by acetate, carbonate, chloride, fluoride, sulphite, hydrazine, hydroxylamine, nitrate, bromide, iodide, sulphide, thiocianate and nitrite. A good correlation (r2 = 0.9782) is obtained between peak area and concentration in the range between 1 and 250 ppb. Samples of tap water spiked with sodium azide (in the range within 25 and 250 ppb) gave per cent average recovery of 98%. The method sensitivity, expressed as signal to noise ratio equal to 3, is 50 ppb when the pH of the interaction reagent is equal to 3.0, 30 ppb for pH 6.4 and 10 ppb at pH 8.0.