title: Fully automated spectrophotometric procedure for simultaneous determination of calcium and magnesium in biodiesel.
abstract: An easily performed stepwise injection (SWIA) procedure based on on-line dilution of biodiesel samples and the formation of color-forming calcium (II) and magnesium (II) complexes with Eriochrome Black T (EBT) in an organic medium followed by spectrophotometric determination is presented. A sample of biodiesel was placed at the bottom of a mixing chamber connected to an automatic SWIA manifold. Isopropyl alcohol was used as the diluent under bubbling. The solution was submitted for on-line spectrophotometric simultaneous determination of calcium and magnesium based on the classic least-square method. The linear ranges were from 2 to 20 μg g(-1) and from 1.2 to 12 μg g(-1), and the detection limits, calculated as 3 s for a blank test (n=5), were found to be 0.6 μg g(-1) for calcium and 0.4 μg g(-1) for magnesium. The sample throughput was 30 h(-1). The method was successfully applied to the analysis of biodiesel samples.
authors: Institute of Chemistry, Saint Petersburg State University, RU-198504 Saint Petersburg, Russia. Electronic address: andrey.shishov.rus@gmail.com.
authors: Andrey Y
authors: AY
authors: Shishov
authors: Institute of Chemistry, Saint Petersburg State University, RU-198504 Saint Petersburg, Russia.
authors: Larisa S
authors: LS
authors: Nikolaeva
authors: Institute of Chemistry, Saint Petersburg State University, RU-198504 Saint Petersburg, Russia.
authors: Leonid N
authors: LN
authors: Moskvin
authors: Institute of Chemistry, Saint Petersburg State University, RU-198504 Saint Petersburg, Russia.
authors: Andrey V
authors: AV
authors: Bulatov
mesh_terms: D019840:2-Propanol / Q000737:chemistry; D001391:Azo Compounds / Q000737:chemistry; D056804:Biofuels / Q000032:analysis*; D002118:Calcium / Q000032:analysis* / Q000737:chemistry; D004983:Ethanolamines / Q000737:chemistry; D016018:Least-Squares Analysis; D008274:Magnesium / Q000032:analysis* / Q000737:chemistry; D013053:Spectrophotometry / Q000379:methods
chemical_list: D001391:Azo Compounds; D056804:Biofuels; D004983:Ethanolamines; C009546:triethanolamine; D008274:Magnesium; C014527:Eriochrome Black T; D019840:2-Propanol; D002118:Calcium
keywords: Biodiesel; Biofuel; Calcium; Determination; Magnesium; Metal; SWIA; Spectrophotometric