title: Spectrophotometric determination of paracetamol with microwave assisted alkaline hydrolysis.
abstract: A novel and rapid spectrophotometric method for the determination of paracetamol is proposed in this paper. The proposed method is based on the microwave assisted alkaline hydrolysis of paracetamol to p-aminophenol that reacts with S2- in the presence of Fe3+ as oxidant to produce a methylene blue-like dye having an absorptivity maximum at 540 nm. The experiment showed that paracetamol could be hydrolysed quantitatively to p-aminophenol in only 1.5 min under radiation power 640 W using a microwave in NaOH medium. The system obeys Beer's law in the range of 0-3.0 x 10(-4) mol l(-1) paracetamol. The molar absorptivity and Sandell's sensitivity were found to be 3.2 x 10(-3) l mol(-1) cm(-1) and 0.047 microg cm(-2), respectively. The relative standard deviation (n=11) was 1.7% for 8.0 x 10(-5) mol l(-1) paracetamol. The method has been applied successfully to analysis of paracetamol in pharmaceutical preparation.
authors.affiliation: Department of Chemistry, School of Chemistry and Materials Science, Shaanxi Normal University, Xi'an 710062, PR China.
authors.forename: Chunli
authors.initials: C
authors.lastname: Xu
authors.forename: Baoxin
authors.initials: B
authors.lastname: Li
mesh_terms: D000082:Acetaminophen / Q000032:analysis*; D018712:Analgesics, Non-Narcotic / Q000032:analysis; D006868:Hydrolysis; D007501:Iron; D008872:Microwaves; D012972:Sodium Hydroxide; D013053:Spectrophotometry / Q000379:methods*; D013440:Sulfides
chemical_list: D018712:Analgesics, Non-Narcotic; D013440:Sulfides; D000082:Acetaminophen; D012972:Sodium Hydroxide; D007501:Iron