Simple, rapid, inexpensive, and sensitive batch and flow injection spectrophotometric methods have been proposed for determination of paracetamol in some pharmaceutical preparations. The proposed methods are based on the coupling reaction between paracetamol and diazotized 4-aminoacetophenone (DAAPH) in a basic medium using sodium hydroxide to produce a pinkish-red azo dye with maximum absorptivity at 500 nm. The reaction conditions and other analytical parameters were studied and optimized for both batch and flow injection procedures. The calibration graphs resulting from measuring the absorbance were linear over the ranges 5.0 ­- 30 and 25 – 180 µg/ml of paracetamol with relative standard deviations 0.26% and 0.18%, and detection limits (0.30, 0.35) µg/ml for batch and flow injection methods respectively. The proposed methods were applied to the analysis of paracetamol in some commercial pharmaceutical preparations. The observed results have a reasonable agreement with those obtained by an HPLC method as a standard certified method from Awamedica company for drug in Erbil-Iraq which based on British pharmacopeia…

A simple, rapid, reproducible and sensitive spectrophotometric method fordetermination of Cobalt (Co2+) was investigated .The method was based on theinteraction of Co2+ with 1-(2-pyridylazo)2-naphthol (PAN), in the presence ofbuffer pH 6 (CH3COOH + CH3COONH4) to give a highly colored species of amolar ratio 1:2 (Co:PAN) .Beers law was obeyed in the range of (0.1-2.5)μg/ml with the molar absorptivity of 3.77x104 L.mol-.cm- at λ max 525 nm.The method was adapted to semi automated flow injection system .The molarabsorptivity was 0.16x104 L.mol-.cm- at λ max 525 nm .Beers law was obeyedin the range (0.3-10) μg/ml. The precision and accuracy studied to bothsystems. The method was applied successfully to the assay of Co2+ in realsample such as real water and waste water, and was well agreed with itscertified value.