title: Flow-injection and sequential-injection determinations of paracetamol in pharmaceutical preparations using nitrosation reaction.
abstract: A simple FI and two different SI systems have been investigated for the determination of paracetamol by employing a simple reagent for a nitrosation reaction. It is based on the on-line nitrosation of paracetamol with sodium nitrite in an acidic medium. The formed nitroso derivative species reacts further with sodium hydroxide to convert it to a more stable compound. The yellow product is continuously monitored at 430 nm. The FI system is very simple and cost effective for fast manual operation (60 injections/h; y = 0.268x + 44.314, r2 = 0.9910 for 400 - 1000 mg/l and y = 0.1687x + 145.72, r2 = 0.9970 for 1000 - 2500 mg/l). The two SI systems with different components and configurations are automated and optimized for the conditions for which no extra dilution is to be required for sample handling: one with a syringe pump and two selection valves (60 samples/h; y = 0.1488x - 4.7297, r2 = 0.9946 for 400 - 1000 mg/l and y = 0.0858x + 63.933, r2 = 0.9849 for 1000 - 2500 mg/l); the other is simpler and more cost-effective, with an autoburette and only one selection valve (15 samples/h; y = 0.0072x + 1.1467, r2 = 0.9977 for 200 - 1000 mg/l and y = 0.0028x + 5.4699, r2 = 0.9879 for 1000 - 2500 mg/l). They have all been applied to assay paracetamol in pharmaceutical preparations. The obtained results agree with those by the US Pharmacopeia method.
authors.affiliation: Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: Rodjana
authors.initials: R
authors.lastname: Burakham
authors.forename: Supunnee
authors.initials: S
authors.lastname: Duangthong
authors.forename: Lop
authors.initials: L
authors.lastname: Patimapornlert
authors.forename: Narong
authors.initials: N
authors.lastname: Lenghor
authors.forename: Suphaphorn
authors.initials: S
authors.lastname: Kasiwad
authors.forename: Lalida
authors.initials: L
authors.lastname: Srivichai
authors.forename: Somchai
authors.initials: S
authors.lastname: Lapanantnoppakhun
authors.forename: Jaroon
authors.initials: J
authors.lastname: Jakmunee
authors.forename: Kate
authors.initials: K
authors.lastname: Grudpan