Quantification of N-acetylcysteine in pharmaceuticals using cobalt phthalocyanine modified graphite electrodes

• Published in: Talanta (Oxford) Vol. 83; no. 5; pp. 1701 - 1706
• Main Authors: Silva, Iranaldo Santos da, Araújo, Marcelo Fernando Antão, Ferreira, Henrique Augusto, Varela, Jaldyr de Jesus Gomes, Tanaka, Sônia Maria Carvalho Neiva, Tanaka, Auro Atsushi, Angnes, Lúcio
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.02.2011; Elsevier
• Subjects: Acetylcysteine - analysis; Acetylcysteine - chemistry; Analytical chemistry; Chemistry; Cobalt phthalocyanine; Electrochemical methods; Electrochemistry - methods; Electrodes; Exact sciences and technology; General, instrumentation; Graphite - chemistry; Indoles - chemistry; N-acetylcysteine; OPG–CoPc; Organometallic Compounds - chemistry; Pharmaceutical Preparations - chemistry; Pharmaceuticals; Voltammetry; Voltammetry; Cobalt phthalocyanine; N-acetylcysteine; OPG–CoPc; Pharmaceuticals; Drug; Use; Method; Chemical sensor; Cobalt; Cyclic voltammetry; Phthalocyanine; Repeatability; Sensitivity; Detection limit; Quality control; Graphite; OPG-CoPc; Amperometry; Peak; Titration; Detection; Quantitative analysis; Flow injection
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2010.11.070

Flow injection analysis (FIA) with amperometric detection was employed for the quantification of N-acetylcysteine (NAC) in pharmaceutical formulations, utilizing an ordinary pyrolytic graphite (OPG) electrode modified with cobalt phthalocyanine (CoPc). Cyclic voltammetry was used in preliminary studies to establish the best conditions for NAC analysis. In FIA-amperometric experiments the OPG–CoPc electrode exhibited sharp and reproducible current peaks over a wide linear working range (5.0×10−5–1.0×10−3molL−1) in 0.1molL−1 NaOH solution. High sensitivity (130mAmol−1cm2) and a low detection limit (9.0×10−7molL−1) were achieved using the sensor. The repeatability (R.S.D.%) for 13 successive flow injections of a solution containing 5.0×10−4molL−1 NAC was 1.1%. The new procedure was applied in analyses of commercial pharmaceutical products and the results were in excellent agreement with those obtained using the official titrimetric method. The proposed amperometric method is highly suitable for quality control analyses of NAC in pharmaceuticals since it is rapid, precise and requires much less work than the recommended titrimetric method.