Amino-functionalised chrysin as adsorbent in dispersive micro-solid phase extraction of selected heavy metal ions from stingless bee honey

Abstract

The study includes the preparation, characterisation, and application of a new adsorbent, 3-aminopropyltriethoxysilane modified chrysin (CHY-APTES), to extract Pb(II), Cr(III), and Cd(II) from stingless bee honey samples using dispersive micro-solid phase extraction (d-µ-SPE) and detected by graphite furnace atomic absorption spectrometer. Characterisation techniques of CHY-APTES including Brunauer-Emmett-Teller surface area analysis, Fourier transform infrared spectroscopy, scanning electron microscopy-energy dispersive x-ray imaging and point of zero charge determination. Several parameters were studied and optimised, such as a desorption time of 15 min, an adsorption time of 3 min, the use of nitric acid solution as the desorption solvent, 120 mg of adsorbent mass, solution pH adjusted to pH 5, and ethanol employed as the dispersive solvent. The results demonstrated good relative recoveries for Pb(II), Cr(III) and Cd(II) in the range of 74.76–116.34 %, 83.59–115.83 % and 89.03–117.66 %, respectively, with good precision at a relative standard deviation≤11.46%. For method sensitivity, the method showed acceptable detection limits (3 S/N) for Pb(II), Cr(III) and Cd(II) extracted from stingless bee honey samples at 43.6, 348.9 and 56.7 µg/kg, respectively. The preconcentration factors calculated for Pb(II), Cr(III), and Cd(II) were 111, 9.5, and 49, respectively. The newly developed CHY-APTES was successfully applied in d-µ-SPE for the first time. It was adequate in terms of analytical performance and simple in preparing stingless bee honey samples via dilution.