Ultrasound-assisted dispersive liquid–liquid microextraction of tetracycline drugs from egg supplements before flow injection analysis coupled to a liquid waveguide capillary cell

Abstract

A simple, rapid, and efficient ultrasound-assisted dispersive liquid-liquid microextraction (US-DLLME) method was developed for extraction of tetracycline residues from egg supplement samples, with subsequent determination by flow injection analysis (FIA) coupled to a liquid waveguide capillary cell (LWCC) and a controlled temperature heating bath. Tetracyclines react with diazotized p-sulfanilic acid, in a slightly alkaline medium, to form azo compounds that can be measured at 435 nm. The reaction sensitivity improved substantially (5.12-fold) using an in-line heating temperature of 45 °C. Multivariate methodology was used to optimize the factors affecting the extraction efficiency, considering the volumes of extraction and disperser solvents, sonication time, extraction time, and centrifugation time. Good linearity in the range 30-600 μg L(-1) was obtained for all the tetracyclines, with regression coefficients (r) higher than 0.9974. The limits of detection ranged from 6.4 to 11.1 μg L(-1), and the recoveries were in the range 85.7-96.4 %, with relative standard deviation lower than 9.8 %. Analyte recovery was improved by approximately 6 % when the microextraction was assisted by ultrasound. The results obtained with the proposed US-DLLME-FIA method were confirmed by a reference HPLC method and showed that the egg supplement samples analyzed were suitable for human consumption.

An overview of the main foodstuff sample preparation technologies for tetracycline residue determination

“…Dispersive liquid-liquid microextraction has also been combined with UAE to isolate tetracyclines from egg supplement samples, followed by spectrophotometric determination using flow analysis. The additional ultrasonication step increased the method extraction capacity by approximately 6% [51]. These works, among others, have demonstrated the versatility of UAE when it comes to increasing tetracycline recovery in different foodstuffs by coupling with several sample extraction processes.…”

“…Protein precipitation in milk and egg samples involves the use of organic solvents including acetonitrile [6,10,23,46,51], methanol [52][53][54][55] or acetone [56], as well as the combination of these solvents with acid compounds, such as trichloroacetic acid [46,[57][58][59][60][61], trifluoroacetic acid [62,63], glacial acetic acid [64][65][66], succinic acid [67,68], citric acid [23,69], formic acid [54,70], or perchloric acid [71]. Other authors have used McIlvaine-EDTA [6,[72][73][74][75][76][77][78][79], sodium citrate [10], oxalate [63], sodium succinate [80] and phosphate [81] buffers as deproteinizing agents for the treatment of these samples.…”

“…In doing so, the analytes in the aqueous sample are rapidly extracted into the fine droplets of the extraction solvent due to the increase in the contact surface between both phases (aqueous and organic). The extraction phase is separated from the cloudy mixture by centrifugation and the enriched analytes in the sedimented phase are determined by the most appropriate analytical technique [51,[140][141][142]. Fig.…”

“…Ultrasound-assisted dispersive liquid-liquid microextraction (US-DLLME) was employed toward the development of a method for extracting tetracycline drugs from egg supplement samples [51]. Residues were rapidly determined by spectrophotometric FIA using a liquid waveguide capillary cell (LWCC) in-line with a controlled temperature heating bath.…”

Adsorptive stripping voltammetric determination of Tetracycline in pharmaceutical capsule formulation using Poly(Malachite green) modified glassy carbon electrode

“…TC (Figure 1), which has significant effect on gram-positive and gram-negative bacteria, is widely used as an important antibiotic to control bacterial infections in both animal models and clinical studies [6,7]. This antibiotic molecule is found in some food products, such as milk [8] and egg [9]. In spite of its use for prevention and control of many bacterial diseases, tetracycline has gastrointestinal side effects, nausea, vomiting, and diarrhea [10].…”