An Inexpensive and Sensitive Method for Speciative Determination of Sn(IV), Sn(II), and Total Sn as Sn(IV) in Selected Beverages by Micellar Improved Spectrophotometry

Springer New York LLCIn the present study, an inexpensive, selective, and micellar sensitive spectrophotometric method for Sn(IV) was developed at 537 nm. The method is based on the formation of ternary complex of Sn(IV) with tartaric acid and Celestine blue in the presence of sodium dodecyl sulfate (SDS) and polyethylene glycol tert-octylphenyl ether (Triton X-114) at pH 3.5. The analytical variables affecting cloud point extraction (CPE) efficiency were optimized in detail. Under the optimized conditions, the calibration graph was linear in the range of 4–350 ?g L?1 with changing dye concentration for Sn(IV) ions. The limits of detection and quantification of the method were found to be 1.3 and 4.3 ?g L?1 for Sn(IV), respectively. Relative standard deviation (RSDs) for five replicate determinations at 20 and 100 ?g L?1 concentration levels were 4.4 and 1.5 %, respectively. Recovery values of spiked samples were obtained in range of 97.7–103.3 %. Matrix effect on the extraction efficiency were also investigated. The method was successfully applied to the determination of Sn(II), Sn(IV) and total Sn in some selected beverages before and after pretreatment with H2O2 in acidic media, prior to analysis. Validity of the method was controlled through the analysis of two certified reference materials. It has been observed that the results are highly compatible with the certified values. © 2014, Springer Science+Business Media New York.Altunay, N.; Department of Chemistry, University of CumhuriyetTurkey; email: [email protected]

Effects of sugarcane juice addition on the population dynamics of Escherichia coli and the presence of Shiga-toxigenic E. coli during the anaerobic codigestion of dairy cattle manure

ABSTRACT: The objective of this study was to evaluate the effects of the addition of sugarcane juice on the population dynamics of Escherichia coli and the presence of Shiga-toxigenic E. coli (STEC) during the anaerobic codigestion of dairy cattle manure. For the overall analyses at the end of a hydraulic retention time of 90 days, ten two-liter batch-type biodigesters were divided into two treatment groups: biodigester containing manure and water (MW) and the biodigester containing manure, water and sugarcane juice (MSC). For monitoring the population dynamics and presence of microorganisms, pH, and volatile acidity, tests were carried out every ten days, on 36 smaller-scale batch biodigesters made of one-liter plastic bottles (18 for each treatment). The reductions in E. coli population over time were significant in the MW (60 days) and MSC (20 days) biodigesters. Inactivation of STEC occurred in a shorter period (40 days in MW and <10 days in MSC). Significant differences were obtained between the two treatments, with the pH values being lower, the concentrations of volatile acids (VA) being higher, and the inactivation of E. coli and STEC being faster in the biodigester with sugarcane juice added. The amount of sugarcane juice applied (7%) suggests its suitability for the sanitization of dairy cattle manure for use as a biofertilizer, given the high reduction in the E. coli population and inactivation of STEC