Two concentration methods for fast and routine determination of caffeine (using HPLC-UV detection) in surface, and wastewater are evaluated. Both methods are based on solid-phase extraction (SPE) concentration with octadecyl silica sorbents. A common “offline” SPE procedure shows that quantitative recovery of caffeine is obtained with 2mL of an elution mixture solvent methanolwater containing a...

Small-scale mining in the Philippines lacks research and technologies for application of an inexpensive environmentally sound treatment its wastewaters. Hence, laboratory-scale fixed-bed column tests were carried out to test evaluate sorbent adsorption performance Philippine Natural Bentonite (PNB) Zeolite (PNZ) against heavy metals present ball mill facilities within Baguio Mining District. Re...

the purpose of this study was to find a relatively inexpensive method for removal of arsenate and arsenite from drinking water. the capability of iranian natural clinoptilolites, relevant synthetic zeolites a and p and iron(п) modified of them was investigated for the uptake of arsenic anions from drinking water. data obtained from ion-exchange using batch (static) technique showed that among t...

The article investigates the sorption method of concentrating rare metals on various sorbents (brands “Purolight”: A-100, A-170, A-172 and BO-020) determines optimal conditions for their extraction. It is shown that extraction molybdenum sorbent “Purolight A-100” was 98%. proposed mechanism consists in formation complexes with functional phosphor basics sulfate groups sorbents. Sorption rhenium...

Tetrakis(4-carboxyphenyl)porphyrin (TCPP) has been loaded on aminopropyl-silica gel by physical adsorption and by direct immobilization through formation of an amide bond to obtain chelating sorbents. These sorbents have been studied for preconcentration and separation of vanadium prior to its determination by atomic absorption spectrometry. Several parameters, such as sorption capacity of the ...

In any biomedical and chemical context, a truthful description of chemical constitution requires coverage of both structure and purity. This qualification affects all drug molecules, regardless of development stage (early discovery to approved drug) and source (natural product or synthetic). Purity assessment is particularly critical in discovery programs and whenever chemistry is linked with b...