The effect of room temperature ionic liquid (RTIL) on the formation of the fluorescence ternary complex oxalate-sodium morin-5-sulfonate (NaMSA)-Aluminium(III) has been studied. In weakly acidic medium and in the presence of RTIL, 1-Butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6), total complex formation is achieved as compared with the formation of the binary complex of NaMSA-Aluminium(III). The fluorescence characteristics of the system allowed the establishment of a very sensitive method for the spectrofluorimetric determination of oxalate ion. The ternary complex formed its highest fluorescence signal at 513 nm and excitation at 420 nm. In these conditions, the method produces a detection limit of 0.57 ng mL(-1). The procedure has been satisfactorily applied to the determination of oxalate ion in a vegetal tissue (spinach leaves).
The concentration of homocysteine (Hcy) rises rapidly after the collection of blood. This feature requires blood to be collected into the anticoagulants EDTA or heparin and the plasma to then be immediately separated; alternatively, the blood may be kept on ice and centrifuged within 1 hour. The use of chemical preservatives has been proposed as a means of stabilising Hcy levels in whole blood after collection. The objective of this study was to determine whether the commonly available fluoride-oxalate (Fl-Ox) and sodium citrate (Na-Cit) containers could stabilise Hcy levels in blood. Our results showed that when blood was collected into potassium EDTA (K-EDTA) tubes, Hcy levels rose from initial levels, on standing at room temperature (approximately 25 degrees C), by an average of 21% after 3 hours and 32% after 5 hours. The initial Hcy levels of blood collected into Fl-Ox and Na-Cit containers, however, were lower, at averages of 89% and 91%, respectively, compared to that of the same samples when collected into K-EDTA tubes. Hcy in these samples subsequently rose on standing, and after 5 hours was, on the average, 10 and 13% higher, respectively, compared with the initial levels in K-EDTA tubes. We conclude that Fl-Ox and Na-Cit do not stabilise Hcy in blood after collection and should not be used as preservatives.
The present study has synthesized poly(4,4'-cyclohexylidene bisphenol oxalate) by the condensation of oxalyl chloride with 4,4'-cyclohexylidene bisphenol, where its efficacy was tested for the solid-phase extraction of DNA. The synthesized polymer in the form of a white powder was characterized by FTIR, TGA-DTG, SEM, and BET analysis. The study utilized solid-phase application of the resulting polymer to extract DNA. The analysis of results provided the information that the extraction efficiency is a strong dependent of polymer amount and binding buffer type. Among the three types of buffers tested, the GuHCl buffer produced the most satisfactory results in terms of yield and efficiency of extraction. Moreover, the absorbance ratio of A260/A280 in all of the samples varied from 1.682 to 1.491, thereby confirming the capability of poly(4,4'-cyclohexylidene bisphenol oxalate) to elute pure DNA. The results demonstrated an increased DNA binding capacity with respect to increased percentage of the polymer. The study has concluded that poly(bisphenol Z oxalate) can be applied as one of the potential candidates for the high efficiency extraction of DNA by means of a simple, cost-effective, and environmentally friendly approach compared to the other traditional solid-phase methods.
Acid content is one of the important quality attributes in determining the maturity index of agricultural product, particularly fruits. Despite the fact that much research on the measurement of acidity in fruits through non-destructive spectroscopy analysis at NIR wavelengths between 700 to 1,000 nm has been conducted, the same response towards individual acids is not well known. This paper presents NIR spectroscopy analysis on aqueous citric, tartaric, malic and oxalic solutions through quantitative analysis by selecting a set of wavelengths that can best be used to measure the pH of the solutions. The aquaphotomics study of the acid solutions has generated R² above 0.9 for the measurement of all acids. The most important wavelengths for pH are located at 918-925 nm and 990-996 nm, while at 975 nm for water.