A rapid and sensitive voltammetric determination of sulphur in biodiesel in samples no treated and treated with TMAH

A simple and fast method to determine water content in biodiesel by electrochemical impedance spectroscopy

“…Regarding the fuel purity, biodiesel contaminants are a major concern. The contaminants include metals [7][8][9], water [10], fatty acid methyl esters [11], sulphur [12], mono-,di-and triacylglycerides and free and total glycerol [13], methanol and ethanol [14], as well as iodine [15]. An important quality parameter for commercialization of biodiesel is the water content.…”

“…There are many established analytical methods for determining the quality parameters of biodiesel to ensure the good performance of the fuel and engines [7][8][9][10][11][12][13][14][15]. For water content analysis, the Karl Fisher method is the most widely adopted, but requires a sophisticated titrator, expensive reagents and qualified personnel to operate the equipment [19,20].…”

Voltammetric determination of sulfur in biodiesel microemulsion using a silver solid amalgam electrode

“…Despite being a complex reaction medium, the detection limits obtained were in the order of 10 −7 mol L −1 , with the smallest LOD being obtained for the LSAdSV technique (0.26 μmol L −1 or 9.5 × 10 −3 mg kg −1 ). Although the LOD is slightly larger than the method described in the literature, 19 the use of hazardous solvents to solubilize the biodiesel samples was not needed in this work. In addition, the LOD found is suitable for determining the sulfur present in the biodiesel, since the LOD obtained is about 5000 times lower than the maximum tolerated limit of the element in the sample.…”

“…[14][15][16][17][18] However, only one method was found in the literature that uses electrochemical techniques to quantify sulfur in biodiesel samples. Viégas, et al 19 developed a voltammetric method using square-wave cathodic adsorptive stripping voltammetry (SW-AdCSV) and a glassy carbon electrode modied with mercury lm. Although the authors achieved low detection limits (3.29 Â 10 À10 mol L À1 ), a pretreatment had to be performed to solubilize the biodiesel sample using tetramethylammonium hydroxide (TMAH) at 90 C. However, TMAH has high toxicity and its dermal exposure can be fatal.…”

The search for organic compounds with TMAH thermochemolysis: From Earth analyses to space exploration experiments

“…Since TMAH is one of the most popular thermochemolysis reagents [14], the studies about TMAH thermochemolysis have been reviewed for its application on the analyses of humic acids [52,84,90,102,103], humic-like substances [104e107], fatty acids [82,88,102,108], phenolic compounds [16,19,81,109], amino acids [64,110], aromatic and aliphatic compounds [29,111], and carbamates [112]. In addition, TMAH is not only a thermochemolysis reagent but is also used as an effective silicon etching solvent [113e115], for dissolution of E. crypticus [116], as a strong base catalyst for transesterification [117], as an extraction solvent for mercury [42,118e121], and Sulfur atom detection [17,122], as a dispersant [123], as a balance-fluid in the fabrication of functionalized-porosity layered-ceramics processes [124], as a digestion solvent for biological samples [125,126], for pH adjustment of solutions [127,128], and for extraction of different halogen elements in soils, such as fluorine [129], chloride [130,131], bromine [132,133], and iodine [134e137]. The detection of iodine can be useful for two main types of applications; the first, measurements of the concentration and distribution of iodine in soils [138e140], and the transference of iodine in different forms between soils and plants [141e146], as well as foods [147,148], have been combined with characterization by inductively coupled...…”