Introduction of a new nitrite-selective optical sensor for food analysis using a copper(II) schiff base complex

A copper(II) Schiff base complex, [Cu(cd4OMeSalMeen)], methyl2{[1methyl2(4methoxyphenolate)mehylidynenitrilo]ethyl}amino1cyclopentene dithiocarboxylate copper(II), was incorporated into triacetylcellulose membrane and applied as ionophore in order to develop an anionselective optical sensor for the analysis of nitrite by absorption spectrophotometry. At optimum pH 3.0, a linear calibration curve was observed for nitrite in the range of 0.50 to 7.00 mgL1 with a detection limit of 0.04 mgL1. The response time of the optode (t95%) was found to be 8–10 min, depending on the nitrite ion concentration. The proposed sensor was fully recovered in nitric acid solution (0.1 M) and had acceptable reproducibility (RSD=1.9%). The optode exhibited good selectivity toward nitrite ion according to hardsoft acid base (HSAB) principle and the formation constant was calculated. The application of the sensor for determination of nitrite content in meat products was quiet successful.