a simple, sensitive and rapid method for determination of trace amounts of nitrite ion in real samples is reported. the reaction is initiated by adding known volumes of a nitrite ion solution of identified concentration to acidic solutions of thionine which causes decolorizaiton of reagent with time. the absorbance changes is then monitored spectrophotometrically at lmax = 602nm at 25 °c. calib...

a column of alumina modified with sodium dodecyl sulfate (sds) and dimethylglyoxime (dmg) was prepared for the preconcentration of trace nickel from water samples for flame atomic absorption spectrometry (faas) determinations. under optimized conditions (ph=7.0; flow rate: 20 mlmin-1) nickel was retained on the column. the nickel collected on the column was eluted with 5 ml of 1 m nitric acid. ...

a partial least squares (pls) calibration model was developed for the simultaneous spectrophotometricdetermination of pb (ιι), cu (ιι) and ni (ιι) using xylenol orange as a chromogenic reagent. the parameterscontrolling behavior of the system were investigated and optimum conditions were selected. the calibrationgraphs were linear in the ranges of 0.0–9.091, 0.0–2.719 and 0.0–2.381 ppm for lead...

a simple, accurate and precise hptlc- densitometry method for the simultaneousdetermination of abacavir, lamivudine and zidovudine in pharmaceutical tablet has beendeveloped. separation of tablet components was performed on aluminum backed hptlc plates(silica gel 60 f254 20×20 cm with 0.2 mm thickness, camag, muttenz, switzerland ) usingmethanol : chloroform : acetonitrile (4 : 8 : 3 v/v). good...

in previous years, identification of fetal cells in maternal blood circulation has caused a new revolution in non-invasive method of prenatal diagnosis. low number of fetal cells in maternal blood and long-term survival after pregnancy limited the use of fetal cells in diagnostic and clinical applications. with the discovery of cell-free fetal dna (cffdna) in plasma of pregnant women, access to...

three antituberculosis medications are investigated in this work consist of rifampicin, isoniazid and pyrazinamide. the ultra violet (uv) spectra of these compounds are overlapped, thus use of suitable chemometric methods are helpful for simultaneous spectrophotometric determination of them. a generalized version of net analyte signal standard addition method (gnassam) was used for determinatio...

in the present work, an adsorptive stripping voltammetric method using a hanging mercurydrop electrode (hmde) was described in order to determine the ultra trace of thiosemicarbazidein different real samples. the method is based on accumulation of thiosemicarbazide on mercuryelectrode. the potential was scanned to the negative direction and the differential pulse strippingvoltammograms were rec...

a new and simple method followed by atomic absorption spectrometry has been developedfor indirect determination of ascorbic acid (aa). the proposed method was based on the oxidationof aa to dehydroascorbic acid with cu2+cation(200mgl-1)in an ammonium thiocyanatesolution atph2.4. aa reduces cu2+to cu+followed by the precipitation of cu+ with scn-. then, the excess ofcu2+in the solution was measu...

this study was intended to evaluate the quality of 30 honey samples, in terms of physicochemical properties such as moisture content, electrical conductivity, ash content, reducing sugars and sucrose, free acidity, ph, diastase activity, and hydroxymethylfurfural (hmf) content. moreover, three methods recommended by the international honey commission for the determination of hmf, including 1) h...

A rapid, simple and sensitive high-performance liquid chromatography method was developed for determination of ciprofloxacin in plasma by means of ultraviolet detection. Ofloxacin was used as an internal standard and separation carried on a Novapak C18 column using a mobile phase of 0.01 M phosphate buffer (pH =2.6): methanol (82: 18 v/v). Extraction of drug was performed from plasma by liquid-...