title: Continuous ultrasound-assisted extraction coupled to a flow injection-flame atomic absorption spectrometric system for calcium determination in seafood samples.
abstract: Calcium was extracted on-line from solid seafood samples by a simple and rapid continuous ultrasound-assisted extraction system. This system is connected to a flow injection manifold, which allows the on-line flame atomic absorption spectrometric determination of calcium. This method enables the analysis of solid samples avoiding time-consuming traditional sample preparation methods and their inherent errors. The on-line manifold for calcium determination is the simplest possible, because a volume of 250 microL of acid extract is injected into an ultrapure water carrier stream. The acid extract was diluted on-line with lanthanum, which also acts as masking agent in order to avoid chemical interferences. The continuous monitoring of the calcium signal was accomplished by flame atomic absorption spectrometry. A Plackett-Burman experimental design was used for the optimisation of the continuous leaching procedure. The method allowed a total sampling frequency of 40 samples per hour, with a relative standard deviation for the complete procedure of 0.9% (for a sample containing 3414.35 mg/kg calcium (dry mass)). The limit of detection was found to be 44.4 mg/kg (dry mass) for 5 mg of sample. The analytical procedure was applied to real seafood samples.
authors.affiliation: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Moreno-Cid
authors.forename: M C
authors.initials: MC
authors.lastname: Yebra
mesh_terms: D002118:Calcium / Q000032:analysis*; D017022:Flow Injection Analysis; D007811:Lanthanum; D017942:Nitric Acid / Q000737:chemistry; D015203:Reproducibility of Results; D017747:Seafood / Q000032:analysis*; D012996:Solutions; D013054:Spectrophotometry, Atomic / Q000295:instrumentation / Q000379:methods*; D013997:Time Factors; D014465:Ultrasonics
chemical_list: D012996:Solutions; C028521:lanthanum chloride; D017942:Nitric Acid; D007811:Lanthanum; D002118:Calcium