Modified silver nanoparticles-enhanced single drop microextraction of tartrazine in food samples coupled with diffuse reflectance Fourier transform infrared spectroscopic analysis

Abstract

The use of tartrazine as an ingredient in foodstuffs is a general practice; tartrazine is added for reasons such as enhancing the color of food and making it attractive and appetizing. Despite food safety standards set by various countries, the evidence of links between tartrazine and hazardous health effects has fostered the necessity to regularly monitor tartrazine levels. In the present work, a new method is demonstrated for the determination of tartrazine in food samples. Modified silver nanoparticles have been used for the extraction of tartrazine in a single drop prior to analysis by diffuse reflectance Fourier transform infrared (DRS-FTIR) spectroscopy. AgNPs were modified with a hydrophobic ligand, and tartrazine was extracted through a single drop microextraction (SDME) mode. The different parameters affecting the extraction efficiency were optimized. Under standard conditions, linear calibrations in the range of 1 to 160 ng mL⁻¹ were achieved with a correlation coefficient of 0.987. The LoD and LoQ were found to be 2.44 and 8.15 ng mL⁻¹, respectively. Good precision was evaluated, with a standard deviation of 0.14 ng mL⁻¹ and relative standard deviations of 1.76% (intraday) and 2.12% (interday) at 10 ng mL⁻¹ for 6 replicate measurements. The applicability of the method to marketed foodstuffs was demonstrated successfully, and recoveries in the range of 90% to 109% were obtained by spiking real samples.