Alpha-benzilmonoxime has been used for the extraction and determination of cobalt at microgram amount. The reagent reacts with cobalt(II) in the pH range of 8.8 - 9.3 to form a yellow-color chelate, which is extracted in chloroform, toluene, and some other non-polar solvents. The chelate is stable in chloroform for about one day. Under the optimum conditions of the a-benzilmonoxime concentratio...

T HAS BEEN NOTED by several authors that in uropepsin determination a major proportion of the total activity is due to conversion of pepsinogen to pepsin, whereas a small proportion of the activity obtained is due to some system other than pepsin. As a result of this, in the quantitative determination of uropepsin some specimens give results which are erroneously high. Several methods for deter...

The pesticide diazinon was determined in its insecticidal formulations by square wave adsorptive stripping voltammetry. The method of its determination is based on the irreversible reduction reaction at the hanging mercury drop electrode. The optimal signal was detected at -1.05 V vs. Ag/AgCl in Britton-Robinson buffer at pH 4.4. Various parameters such as pH, buffer concentration, frequency, a...

We have established the optimal conditions for use of sodium borohydride as the reducing agent before the direct determination of mercury in water, urine, and blood by atomic absorption spectroscopy. We evaluated the effects of pH, temperature, and cupric sulfate concentration on the direct determination of both organic and inorganic compounds of mercury. Accurate and precise quantification of ...

A new chemically modified carbon paste electrode for cesium(I) ion determination based on potassium zinc hexacyanoferrate (PZHCF) as an ionophore was prepared. The electrode exhibits a Nernstian response for Cs(I) ions over a wide concentration range from 1 × 10 to 1 × 10 mol·L with a slope of 58 ± 0.5 mV·decade. It has a response time of about 35 s and can be used for a period of 3 months with...

In this study a sensitive, simple and accurate spectrophotometric method was suggested for determination of tamsulosin in bulk powder and pharmaceutical dosage form based on the formation of an ion-pair complex between the drug and bromocresol green in a buffer solution at pH 3.5. The formed yellow color complex was extracted with chloroform and measured at 415 nm. The optimum reaction conditio...

The electroreduction behaviour and determination of cefoperazone using a hanging mercury drop electrode were investigated. Cyclic voltammograms of cefoperazone recorded in universal Britton-Robinson buffers pH 3-6 exhibited a single irreversible cathodic peak. The process was adsorption-controlled. Britton-Robinson buffer 0.04 M pH 4.0 was selected as a supporting electrolyte for quantitative p...

A phenylboronate affinity gel has been investigated for use in the prepurification of urine before "high-performance" liquid chromatography and electrochemical determination of 5-S-L-cysteinyl-L-dopa. At pH 5.6 this naturally occurring 5-S-cysteinyldopa was adsorbed on a phenylboronate column and was quantitatively eluted with trichloroacetate, pH 3.0. This pretreatment of urine before "high-pe...

Silica gel, sequentially modified with polyhexamethylene guanidine and pyrocatechin-3,5-disulfonic acid (Tiron), was suggested for sorption separation and determination of Fe(III) and Fe(II). It was found that quantitative extraction of Fe(III) and its separation from Fe(II) were attained at pH 2.5-4.0, while quantitative extraction of Fe(II) was observed at pH 6.0-7.5. An intensive signal with...

The isoelectric point (pI) of a protein is a key characteristic that influences its overall electrostatic behaviour. The majority of conventional methods for the determination of the isoelectric point of a molecule rely on the use of spatial gradients in pH, although significant practical challenges are associated with such techniques, notably the difficulty in generating a stable and well cont...