The reaction of aluminium(III) with Hydroxynaphtol Blue (HNB) in aqueous media at apparent pH 5.5 results in a red complex that is stable for at least 4 hr. Beer's Law is obeyed up to 1.6 microg/ml of aluminium(III) with an apparent molar absorptivity of 1.66 x 10(4) l.mol(-1). cm(-1) at 569 nm. This paper proposes procedures for aluminium(III) determination by ordinary and first-derivative spe...

We describe a method for the measurement of protein-bound malondialdehyde with the thiobarbituric acid reaction in human plasma using second-derivative spectrophotometry. Calibration was done by spectrum height measurement from the baseline at 532 nm. The data were compared with those obtained by using conventional absorbance and fluorimetric measurements. The results were linear from 0.2 to 80...

A simple chemometric-assisted UV-spectrophotometric method was used to study the compatibility of clindamycin hydrochloride (HC1) with two commonly used natural controlled-release polymers, alginate (Ag) and chitosan (Ch). Standard mixtures containing 1:1, 1:2, and 1:0.5 w/w drug-polymer ratios were prepared and UV scanned. A calibration model was developed with partial least square (PLS) regre...

The aim of the present work was to develop a simple and rapid method for determination of theophylline (THP) and guaifenesin (GU) in syrup without involving any preparation operations like separation or masking. A HPLC and two spectrophotometric methods based on the derivation of the main spectra are described for the determination of THP and GU in combined pharmaceutical syrup form. The first ...

Weakly charged cationic nanoparticles cause structural changes including local denaturing and compaction to DNA under mild conditions. The charged ligands bind to the phosphate backbone of DNA and the uncharged ligands penetrate the helix and disrupt base pairing. Mobility shifts in electrophoresis, molecular dynamics, and UV-vis spectrophotometry give clues to the details of the interactions.

The results of determination of trace quantites of selenium in various commercial natural fruit juices by three independent methods: atomic absorption spectrometry (AAS), spectrophotometry (UV-VIS) and spectrofluorometry (SF) were presented. The level of selenium in any of the analysed samples of fruit juices did not exceed the WHO recommended level of 0.010 mg/l for drinking water.

A biologically active vitamin D(3) metabolite ("peak V metabolite") more polar than 25-hydroxycholecalciferol has been isolated from chicken intestines in pure form as a mono(trimethylsilyl)ether derivative. The molecule has been identified as 1,25-dihydroxycholecalciferol by means of mass spectrometry, ultraviolet absorption spectrophotometry, and specific chemical reactions.

In this study, different derivative spectrophotometric methods are proposed for the simultaneous determination of chlorpheniramine maleate (CP), phenylephrine HCl (PE) and phenylpropanolamine HCl (PP) in their ternary mixtures and in pharmaceutical dosage forms. Spectra of single component and ternary mixtures of various concentrations and combinations from zero- to fourth-derivation were obtai...