Determination of Vitamin B12 and cobalt in egg yolk using vortex assisted switchable solvent based liquid phase microextraction prior to slotted quartz tube flame atomic absorption spectrometry

• Published in: Food chemistry 2019-07, Vol.286, p.500-505
• Main Authors: Tekin, Zeynep, Erarpat, Sezin, Şahin, Ayşe, Selali Chormey, Dotse, Bakırdere, Sezgin
• Format: Article
• Language: English
• Subjects: Cobalt; Cobalt - analysis; Egg yolk; Egg Yolk - chemistry; Limit of Detection; Liquid Phase Microextraction - methods; Quartz - chemistry; Semicarbazones - chemistry; Slotted quartz tube; Solvents - chemistry; Spectrophotometry, Atomic - methods; Switchable solvent; Vitamin B 12 - analysis; Vitamin B12; Water Pollutants, Chemical - analysis
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2019.02.036

•This study proposed an environmentally friendly and low cost determination method for cobalt.•Cobalt in the Vitamin B12 was determined with the help of a microextraction technique.•The spiking experiment gave high recovery results for egg yolk and Vitamin B12.•Slotted quartz tube was used to increase sensitivity of the FAAS system. A switchable solvent based liquid phase microextraction (SS-LPME) has been proposed for the determination of cobalt in egg yolk and Vitamin B12 at trace levels. N,N-Dimethylbenzylamide (DMBA) was used as a switchable solvent and converted to protonated DMBA form by the addition of dry ice. Cobalt was complexed with 1,5-diphenylcarbazone (DPC) and extracted into the DMBA phase. After the extraction, HNO3 was added to increase nebulization efficiency of the DMBA phase. Slotted quartz tube (SQT) was combined with FAAS to enhance the detection power of the system when compared to the conventional FAAS. Under the optimum conditions, limit of detection values were recorded as 75 µg L−1 for FAAS, 33 µg L−1 for SQT-FAAS, 7.6 µg L−1 for SS-LPME-FAAS, and 2.3 µg L−1 for SS-LPME-SQT-FAAS. The developed method was applied for the determination of cobalt in egg yolk and Vitamin B12 and the recovery results were found in the range of 105–114% with 0.30–7.6 standard deviation values (n = 3).