New Extraction Approach Combined with HPLC-UV to Monitor Chloramphenicol in Milk and Chicken

A study co-authored by Fatemeh Mehrabi and Mehrorang Ghaedi of Yasouj University in Yasouj, Iran and published in the Journal of Chromatography A analyzed chloramphenicol (CAP) in milk and chicken samples using high performance liquid chromatography-ultraviolet (HPLC-UV), following syringe-to-syringe magnetic fluid phase microextraction using magnetic nanoparticles based on a deep eutectic solvent (DES) (1).

Fresh raw chicken breast, top view. Culinary cooking ingredients | Image Credit: © petrrgoskov - stock.adobe.com

Chloramphenicol (CAP) is a broad-spectrum antibiotic that is known to be toxic to humans in large doses. Its use in food-producing animals and as a veterinary drug has been banned in many countries due to its potential to cause aplastic anemia in humans. Even low levels of exposure to CAP in food can cause serious health effects, including damage to the bone marrow, which can lead to anemia, infections, and an increased risk of cancer. Due to its toxicity, strict monitoring and regulation are required to ensure that CAP is not present in food at harmful levels. Many countries ban CAP in the livestock production process, though some continue to use it illegally because of its cost-effectiveness. HPLC-UV is considered an efficient tool to monitor trace CAP levels in samples of food products such as milk and chicken because it is a low-cost and easily applicable method.

Although HPLC-UV was utilized in this study to deliver reliable results, much of the research focus was on developing a newer, greener, and viable extraction technique. Up to now, the best candidates for preconcentration and enrichment of hazardous drugs in food samples have been liquid-phase microextraction (LPME), solid-phase extraction (SPE), and solid-phase microextraction (SPME). Within these methods, the new approach of syringe-to-syringe magnetic fluid phase microextraction is considered difficult to automate, yet it is not only low-cost, high-performing, and effective, but also green and sustainable.

To achieve this extraction, the researchers used magnetic nanofluid containing magnetic nanoparticles based on a DES. Nanoparticles are often metallic, ceramic, or carbon in nature, commonly coated with a surfactant layer that is stabilized by a carrier liquid to create the nanofluid. Organic solvent or water-based nanofluids can be applied to solar water heating, engine and nuclear system cooling, drilling, and lubricating. DESs, frequently made by combining ammonium salts as hydrogen bond acceptors (HBA) and donors (HBD), pointed the way to a new, green solvent for this study.

DES can be used to extract chloramphenicol (CAP) from food samples for high performance liquid chromatography with ultraviolet detection (HPLC-UV) analysis. DES is a mixture of two or more components that form a liquid at room temperature with unique properties such as low toxicity, low cost, and high solubility. When mixed with a food sample containing CAP, DES can dissolve the compound and facilitate its separation from the food matrix. The extracted CAP can then be analyzed by HPLC-UV for quantification and detection purposes. This method is becoming popular due to its simplicity, efficiency, and ability to reduce sample preparation steps.

Upon preconcentration and enrichment of CAP in the milk and chicken samples studied, central composite design was additionally used to find the optimum conditions of effective factors, the optimum values of which were then used to evaluate figures of merit. The combined processes yielded low limits of detection (0.2 ng m/L) and quantitation (0.67 ng/mL), and a linear range with a coefficient of determination (R²) of 0.996. CAP relative recoveries in the samples had a range of 90.3% to 95.1%, with relative standard deviations lower than 4.2%.

Given the importance of detecting even trace amounts of CAP in food products derived from animals, HPLC-UV is gaining widespread interest for use in conjunction with these new and emerging extraction methods because of its capability for reproducible results.

Reference

(1) Mehrabi, F.; Ghaedi, M. Magnetic nanofluid based on green deep eutectic solvent for enrichment and determination of chloramphenicol in milk and chicken samples by high-performance liquid chromatography-ultraviolet: Optimization of microextraction. J. Chromatogr. A 2023, 1689, 463705. DOI: 10.1016/j.chroma.2022.463705