A novel, simple and low cost method for the determination of nitrite using headspace single-drop
microextraction and cuvetteless ultraviolet–visible micro-spectrophotometry is described. A Griess
reagent-containing aqueous microdrop exposed to the headspace was used as extractant of the volatile
nitrogen oxides generated from nitrite by direct acidification of the aqueous sample. Experimental param-
eters affecting the headspace single-drop microextraction performance such as composition and volume
of the extractant phase, sample volume, concentration of acetic acid, ionic strength, sample agitation,
temperature and microextraction time were systematically examined. Measurements were carried out at
540 nm under optimized conditions. A detection limit of 1.5 gL
−1
and an enrichment factor of 193 were
achieved. Intra-day repeatability and inter-day reproducibility, expressed as relative standard deviation,
were 3.5% (n = 7) and 10.6% (three consecutive days), respectively. The proposed method, characterized
by its enhanced sensitivity and selectivity in comparison with the standardized colorimetric assay, was
successfully applied to the analysis of several environmental water samples.