The increasing concentration of nitrite in water, river and lakes has caused critical hazards to public health and the environment. Nitrites are mostly used as preservatives. However, the continuous ingestion of these ions can have toxic effects on animal and human health. Nitrite can reacts irreversibly with hemoglobin to produce methemoglobin, so reducing blood capacity to oxygen traort. Nitrite also can harm the nervous system. Very larg amount of nitrite typically used for food preservation has been proved to be carcinogenic as it serves as a precursor to the formation of N-nitrosamins. Therefore, determination of nitrite is of great importance due to its harmful effects on human health, So sensitive , selective, and precise methods are required for determination of nitrite. Hollow fiber based liquid-liquid-liquid microextraction (HF-LLLME) followed by flow injection analysis and spectrophotometric detection was applied as a simple and sensitive method for determination of nitrite in water and food samples. Flow injection system, was a conventional HPLC system (without a chromatographic column) and spectrophotometric detector. The extraction of nitrite was carried out using isoamyl benzoate contains 4% surfactant (Aliquat 336) as the organic phase for filling the pores of the hollow fiber, and 0.25 M NaI solution as acceptor phase in the lumen of the fiber. the extracted nitrite ions in sample react with sulfanilic acid (SA) and phenol to form an azo dye,showing a maximum absorption at 440 nm. The factors affecting the HF-LLLME including type of organic solvent , concentration of surfactant , type and concentration of alt in the acceptor, extraction time and stirring rate were investigated and optimized. Moreover the interference of some anions and cations were also investigated, the enrichment factor was 75. The limit of detection was 0.6 µg/L. The method was applied to the determination of nitrite in various water and food samples.
