A hydrophobic deep eutectic solvent‐based vortex‐assisted dispersive liquid–liquid microextraction combined with HPLC for the determination of nitrite in water and biological samples

Abstract

In recent years, hydrophobic deep eutectic solvents as new generation of green solvents have attracted wide attention in liquid microextraction technique. In this article, four hydrophobic deep eutectic solvents composed of trioctylmethylammonium chloride and oleic acid were designed and prepared firstly. Combined with high‐performance liquid chromatography, these deep eutectic solvents were used as an extraction solvent in vortex‐assisted dispersive liquid–liquid microextraction for the selective enrichment and indirect determination of trace nitrite from real water and biological samples. This method is based on the diazotization‐coupling reaction of nitrite with p‐nitroaniline and diphenylamine in acidic water, and then the nitrite is quantified indirectly by measuring the obtained azo compounds. Some factors influencing the extraction efficiency, including the reaction and extraction conditions, were investigated. Under the optimized conditions, the method has a linear range of 1–300 μg/L with a correlation coefficient of 0.9924, limit of detection of 0.2 μg/L, limit of quantitation of 1 μg/L, intraday and interday relative standard deviations of 4.0 and 6.0%. This method was successfully applied in determination of nitrite from three environmental water and two biological samples with the recovery in the range of 90.5–115.2%. In addition, these results were well agreement with those obtained by the conventional Griess method.

Microextraction Techniques with Deep Eutectic Solvents

“…After the optimization of certain factors, the LOD and LOQ were 0.2 and 1 µg/L. The method was applied to tap water, lake water, well water, human urine, and saliva samples spiked with specific quantities, with recoveries (%) ranging between 90.5 and 115.2 [115]. Faraji used DESs in a VA-DLLME for the simultaneous determination of two auxins (indole-3-acetic acid (IAA) and 1-naphthaleneacetic acid (NAA)) in tap water, apple juice, orange juice, and banana juice, followed by HPLC.…”

Green and enhanced extraction of coumarins from Cortex Fraxini by ultrasound‐assisted deep eutectic solvent extraction

“…DESs were prepared by using the heating method. Accurately weighed raw materials were added in a glass flask and stirred in a water bath at 80 • C to generate homogeneous liquid, and a proper amount of water was added during DES preparation as reported [18][19][20][21][22]. The produced DESs contain 17 groups, and the whole list of the abbreviations of prepared DESs is displayed in Table 1.…”

Combining ultrasound‐assisted extraction and vortex‐assisted liquid–liquid microextraction for the sensitive assessment of aflatoxins in aquaculture fish species

“…On other occasions, the extraction solvent dispersion is achieved by pulling in and pushing out the mixture of aqueous sample solution and extraction solvent repeatedly in a glass syringe (air‐assisted dispersive liquid–liquid microextraction) . DLLME extractive capabilities can be also increased by fast shaking using a vortex (vortex‐assisted liquid–liquid microextraction [VALLME]), which leads to a fast extracting solving dispersion and a fast mass transfer from the aqueous phase to the organic extractant . Advantages of VALLME are mainly the low price of the shaking device (vortex are widely available) in comparison to ultrasound and microwaves apparatus.…”