Direct Potentiometric Determination of N-acetyl-L-cysteine (NAC) in Real Samples by Using “home made” Iodide ISE

Direct potentiometric method for determination of NAC in pharmaceuticals by using “home-made” iodide ISE is described. Iodide ISE membrane was made of AgI:Ag2S:PTFE = 1:1:2. Proposed method is very inexpensive, simple and reasonably fast method for determination of NAC in acetic buffer, pH = 5 without pretreatment of pharmaceuticals and determination is based on the reaction between NAC and Ag+ from electrode membrane. Described method has linear response range for NAC from 2×10−5 to 1×10−2 mol L−1 with limit of detection of 7.8×10−6 mol L−1. Found concentrations of NAC are in very good agreement with declared ones with standard deviation values in range 0.13-3.41%.