Document Type : Original Article
Department of Chemistry, College of Science, University of Basrah, Basrah 61001, Iraq
A new and simple method for the selective and sensitive determination of trace amounts of nitrite in soil samples is developed by a combination of cloud point extraction (CPE) and spectrophotometry technique. The procedure is based on the Griess reaction on 3,3`-dimethyl benzidine with nitrite in the presence of 1-naphthol in acidic media to form a yellow diazo dye, which shows absorption at lambda max 455 nm. The formation of colored diazo dye is followed by extraction into the Triton X-114-rich phase. CPE method parameters such as surfactant amount, temperature, and incubation time are evaluated and optimized. The results showed a very good linear range of 10-1250 µgL-1, with good regression coefficients (R2) ≥ 0.9997 and a preconcentration factor of 12.5. The limit of detection (LOD) describes as 3SDblank/m, and the limit of quantification (LOQ) describes as 10SDblank/m, where ‘m’ is the slope of the calibration curve and they are equal to 7.50 and 22.71 µgL-1 respectively. The recommended method can apply to determine the ultra-trace amount of nitrite in soil samples.