Ultrasound-Assisted Matrix Solid-Phase Dispersion Coupled with Reversed-Phase Dispersive Liquid-Liquid Microextraction for Determination of Vitamin C in Various Matrices

For the first time, ultrasound-assisted matrix solid-phase dispersion (UA-MSPD) and reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) were coupled for determination of vitamin C in various matrices without any filtration and sample transfer from the original vessel. Samples were analyzed using a high-performance liquid chromatography (HPLC) instrument with ultraviolet absorption detector. Influential parameters of UA-MSPD and RP-DLLME such as sorbent, elution solvent and its volume, sample to sorbent ratio, ultrasonic time and amplitude, pH of aqueous phase and its volume, water-immiscible organic solvent and its volume, and centrifuging time were investigated and optimized. Under the optimized conditions, limit of detection and quantitation values were 0.84 and 2.5 ng/mL, respectively. Recovery data for several real samples were obtained in the range of 67.0-88.0% with relative standard deviation (RSD) less than 7.5%. The proposed method was successfully applied to quantitatively determination of vitamin C in several solid and semi-solid samples.