Abstract
The construction and characteristic performance of
s-benzylthiuronium (
s-BT)–PVC membrane sensor responsive for cetylpyridinium chloride (CPC) are described. The sensor is based on the use of
s-BT–tetraphenylborate (TPB) ion pair as electroactive material in PVC matrix in presence of dioctylphthalate as solvent mediator. The membrane sensor shows a fast, stable and near Nernstian response for CPC over the concentration range of 6
×
10
−6–1
×
10
−3
M at 25
°C and pH range 6–12 with cationic slope of 57.0
±
0.4. The lower detection limit is 4
×
0
−6
M and the response time is 10–30
s. Selectivity coefficients for CPC relative to a number of different species were investigated, which there is negligible intereferences are caused by most of investigated cations, anions, and some organic compounds. The determination of 2.0–350.0
μg/ml of CPC in aqueous solutions shows an average recovery of 98.8%and a mean relative standard deviation of 1.87% at 64.0
μg/ml. The determination of CPC in mouthwash pharmaceutical solution gave results that compare favorably with those obtained by the British pharmacopoeia method. The
s-benzylthiuronium electrode has been utilized as an end point indicator electrode for some precipitation titration reactions involving CPC as titrant.