پديدآورندگان :
Rahimi Afshin Afshinrahimi89@yahoo.com Department of Chemistry, University of Guilan, University Campus 2, Rasht, Iran / Research Laboratory, SumTech Co. (Newsaad Hygienic and Cosmetics), Pardis St., Sanaat 1 BLV., 1st Intrance, Rasht Industrial City, Iran; , Zanjanchi Mohammad Ali Department of Chemistry, University of Guilan, University Campus 2, Rasht, Iran / Department of Chemistry, Faculty of Science, University of Guilan, Rasht, Iran , Bakhtiari Sadjad Research Laboratory, SumTech Co. (Newsaad Hygienic and Cosmetics), Pardis St., Sanaat 1 BLV., 1st Intrance, Rasht Industrial City, Iran , Dehsaraei Mohammad Department of Chemistry, Faculty of Science, University of Guilan, Rasht, Iran / Research Laboratory, SumTech Co. (Newsaad Hygienic and Cosmetics), Pardis St., Sanaat 1 BLV., 1st Intrance, Rasht Industrial City, Iran
كليدواژه :
Ultrasound assisted extraction , Magnetic solid phase extraction , Three dimensional graphen , caffeine
چكيده فارسي :
A simple and efficient extraction method composed of ultrasound assisted extraction (UAE)-Magnetic solid phase extraction (MSPE) combined with gas chromatography system was applied for extraction and determination of caffeine in food samples. Three dimensional graphen-Fe3O4 nanoparticles was successfully synthesized and used as adsorbent in MSPE step. The properties and morphology of synthesized adsorbent were characterized by Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), VSM, XRD, Raman spectroscopy, BET and BJH methods. The influence of main parameters affecting the extraction efficiency such as temperature, ultrasound time, the amount of nanoparticles (adsorbent), pH, amount of salt concentration and desorption condition were investigated and optimized. Under the optimized experimental conditions, the figure of merit results showed excellent linear dynamic range (0.5-500 µg mL-1), with determination coefficient (R2) higher than 0.996 and limits of detection (LOD) of 0.1 µg mL-1 (S/N = 3). Intra- and inter-day relative standard deviations (RSDs) were less than 5.9 and 7.1 % (n = 5), respectively. The method was successfully applied for determination of caffeine in different food samples including teas (green, black, oolong and tea bag), coffees (coffee bean, espresso, cacao powder and Nescafe coffee) and chocolate (white chocolate, 52 and 72% dark chocolate).
