title: Simultaneous in situ derivatization and ultrasound-assisted dispersive magnetic solid phase extraction for thiamine determination by spectrofluorimetry.
abstract: A simple and rapid method for the simultaneous in situ derivatizaion, preconcentration and extraction of thiamine (vitamin B1) as a model analyte was developed by a novel quantitative method, namely ultrasound-assisted dispersive magnetic solid phase extraction spectrofluorimetry (USA-DMSPE-FL) from different real samples. This method consists of sample preparation, in situ derivatization, exhaustive extraction and clean up by a single process. High extraction efficiency and in situ derivatization in a short period of time is the main advantages of this procedure. For this purpose, the reusable magnetic multi-wall carbon nanotube (MMWCNT) nanocomposite was used as an adsorbent for preconcentration and determination of thiamine. Thiamine was, simultaneously, in situ derivatized as thiochrome by potassium hexacyanoferrate (III) and adsorbed on MMWCNT in an ultrasonic water bath. The MMWCNTs were then collected using an external magnetic field. Subsequently, the extracted thiochrome was washed from the surface of the adsorbent and determined by spectrofluorimetry. The developed method, which has been analytically characterized under its optimal operating conditions, allows the detection of the analyte in the samples with method detection limits of 0.37 µg L(-1). The repeatability of the method, expressed as the relative standard deviation (RSD, n=6), varies between 2.0% and 4.8% in different real samples, while the enhancement factor is 197. The proposed procedure has been applied for the determination of thiamine in biological (serum and urine), pharmaceutical (multivitamin tablet and B complex syrup) and foodstuff samples (cereal, wheat flour, banana and honey) with the good recoveries in the range from 90% to 105%.
authors.affiliation: Department of Analytical Chemistry, University College of Science, University of Tehran, P.O. Box 14155-6455, Tehran, Iran. Electronic address: ghdaneshvartarigh@yahoo.com.
authors.forename: Ghazale Daneshvar
authors.initials: GD
authors.lastname: Tarigh
authors.affiliation: Department of Analytical Chemistry, University College of Science, University of Tehran, P.O. Box 14155-6455, Tehran, Iran. Electronic address: Shemiran@khayam.ut.ac.ir.
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Shemirani
mesh_terms: D000327:Adsorption; D002523:Edible Grain / Q000737:chemistry; D005433:Flour / Q000032:analysis; D005504:Food Analysis / Q000379:methods*; D006722:Honey / Q000032:analysis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008280:Magnetics; D028521:Musa / Q000737:chemistry; D053761:Nanocomposites / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry; D004364:Pharmaceutical Preparations / Q000737:chemistry; D015203:Reproducibility of Results; D012965:Sodium Chloride / Q000737:chemistry; D012972:Sodium Hydroxide / Q000737:chemistry; D052616:Solid Phase Extraction / Q000379:methods*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013607:Tablets / Q000737:chemistry; D013831:Thiamine / Q000032:analysis* / Q000302:isolation & purification; D014908:Triticum / Q000737:chemistry; D014465:Ultrasonics; D014803:Vitamin B Complex / Q000097:blood / Q000737:chemistry / Q000652:urine; D014815:Vitamins / Q000737:chemistry
chemical_list: D037742:Nanotubes, Carbon; D004364:Pharmaceutical Preparations; D013607:Tablets; D014815:Vitamins; D014803:Vitamin B Complex; D012965:Sodium Chloride; D012972:Sodium Hydroxide; D013831:Thiamine
keywords: Derivatization; Magnetic multi-wall carbon nanotube; Preconcentration; Thiamine (vitamin B(1)); Ultrasound solid phase extraction