Reverse flow injection analysis of trace amounts of nitrite using saffron as natural reagent

Monitoring and determination of nitrite ion is very important because of its environmental impacts and many agricultural and food industries applications and also as a precursor reagent in the formation of cancer in human bodies. Current study aided to propose and develop a new, safe, simple and inexpensive automatic method for the determination of nitrite ions by reverse Flow Injection Analysis (rFIA) which decreases effectively consuming of the reagents in the green analytical method. The method is based on the reaction of the nitrite ion with saffron as natural reagent in acidic media. The reaction process is monitored via visible photometer in the wavelength of 440 nm. The influences of chemical and instrumental variables in the special rFIA manifold were studied and optimized. In the optimal conditions, the calibration curve is linear in the concentration ranges of 3.0 to 15.0 ngml-1 with the sensitivity of 1.4 and 30.0 to 180.0 ngml-1 with the sensitivity of 0.36. RSD for repetitive determination of 100.0 ngml-1 nitrite ion were obtained as 1.8. In the optimum conditions more than 130 analyses per one hour can be analyzed by the developed method. This method was also applied for the determination of nitrite content in the tap and river water as real samples with satisfactory results.