Ultrasound-assisted micro-solid-phase extraction using a MIL-53(Al)/Diaion SP-850 composite for trace determination of erythrosine in food and environmental samples

In this work, a dispersive microsolid phase extraction and determination of erythrosine from water, food and environmental samples was performed. A MIL-53(Al)/Diaion SP-850 composite was prepared and characterised by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller (BET). Micro-solid phase extraction parameters, such as pH, adsorbent amount, adsorption and desorption duration, sonication time, sample volume, eluent type and volume were investigated before the application of the method to real samples. Buffer pH 3.0 phosphate, 10 mg of adsorbent, 60 seconds for adsorption, 3 min for desorption, sample volume of 40 mL and 1 mL absolute ethanol were the optimum conditions resulted from this investigation. Along with the optimisation of the technique, the environmentally friendliness and environment sustainability of the method, namely, Analytical GREEnness Metric Approach (AGREE) and Analytical Greenness Metric for Sample Preparation (AGREEprep) and the Bluenness evaluation (BAGI) were evaluated demonstrating 0.68, 0.75, and 60.0 respective scores. Combining with UV–vis spectrophotometer, the developed ultrasonic-assisted dispersive micro-solid phase extraction method exhibited a linear range of 2.4–3000 µg L−1, low detection limit of 0.80 µg L−1 and a preconcentration factor (40). The method was applied for preconcentration and separation of erythrosine in food and environmental samples presented extraction recovery values ranging 91–102% with relative standard deviation of 4.2%.