A Simple Spectrophotometric Determination of Phosphate in Sugarcane Juices, Water and Detergent Samples

Abstract

A simple spectrophotometric method is developed for the determination of phosphate in sugar cane juice, water and detergent samples. The method is based on the formation of phosphomolybdate with added molybdate followed by its reduction with sodium sulphide in aqueous sulfuric acid medium. The system obeys Lambert-Beer’s law at 715 nm in the concentration range 0.3-12.24 ppm. Molar absorptivity, correlation coefficient and Sandell’s sensitivity values were found to be 6.1x103mol-1cm-1, 0.999 and 0.0156 µg cm-2respectively. The results obtained were reproducible with acceptable standard deviation 3.7% and relative error 3.4%. For a comparison of the method phosphate present in various samples were also determined separately following an official method. The results of the developed method compare well with those of the official method.

Removal of chromate and phosphate anion from aqueous solutions using calix[4]aren receptors containing proton switchable units

“…3. An aqueous solution of Na 2 Cr 2 O 7 showed no extraction into a phase in the absence of the extractant: calix [4]arene derivatives (4)(5)(6)(7). The extraction data (Fig.…”

“…The dichromate and phosphate anion extraction experiments of calix [4]arene derivatives 4-7 were studied by liquid-liquid extraction experiments following the literature procedures [5,33]. An aqueous solution (10 mL) containing sodium dichromate and/or disodium hydrogen phosphate at a concentration of 1 × 10 −4 M was pipette into a vial, and a few drops of 0.01 M KOH/HCl solution were added in order to obtain the desired equilibrium pH and 10 mL of 1 × 10 −3 M calixarene ligand in CH 2 Cl 2 .…”

“…The mixture was shaken vigorously in a stoppered glass tube with a mechanical shaker for 2 min, and then magnetically stirred in a thermostated water bath at 25 • C for 1 h, and finally left standing for an additional 30 min. Then the concentration of dichromate or phosphate ion remaining in the aqueous phase was determined spectrophotometrically as described previously [5] and [30]. Blank experiments showed that no dichromate or phosphate extraction occurred in the absence of the calix [4]arene.…”

“…Many phosphorus compounds cause serious health problems. On the other hand, it plays an important role in biochemical processes and it is a key factor in the eutrophication of surface water [5,6]. Phosphorus exists in a wide variety of physicochemical parameter forms in natural waters, and they are highly mobile within aquatic ecosystem [7].…”

Qualidade tecnológica da cana-de-açúcar sob adubação com torta de filtro enriquecida com fosfato solúvel

“…Na cana-de-açúcar o fósforo assume grande importância no enraizamento e no perfilhamento e, portanto, na produtividade final e no rendimento de açúcar (Santos, 2009). A deficiência de fósforo também é problemática pois, segundo Mahadevaiah et al (2007), reduz a absorção de nitrogênio e dificulta a clarificação do caldo durante a fabricação do açúcar, elevando o custo de fabricação em virtude da necessidade de adição de fosfatos solúveis para atingir o teor ideal de P 2 O 5 , fundamental para uma clarificação eficiente.…”