Electrostatically in situ binding of zwitterionic glycine on the surface of MGO for determination of nitrite in various real samples.

Zwitterionic dispersive magnetic solid phase extraction (ZI-DMSPE) was developed through in situ binding of glycine on the magnetic graphene oxide, electrostatically. This highly selective sorbent was applied for the determination and preconcentration of trace levels of nitrite in soil, sausage, water samples (tap, mineral, and rain), and vegetables (potato, onion, spinach, radish, and lettuce) prior to its determination by UV-Vis spectrophotometry. The major advantage of the method is the analyte adsorption in both acidic and basic media. The sorbent was characterized by SEM, XRD, EDS, and FT-IR. Several parameters affecting ZI-DMSPE were optimized. Under the optimal conditions, LOD and RSD were obtained 17 ng L and 1.3% respectively. Preconcentration factor and sorption capacity of the proposed method were 666 and 238 mg g respectively. Accuracy was assessed by comparing results with those obtained by direct determination using ion chromatography and spiked real samples.