A simplified method for the determination of several fish drugs in edible fish and shrimp by high-performance liquid chromatography

Determination of tetracycline, oxytetracycline and chlortetracycline residues in seafood products of Saudi Arabia using high performance liquid chromatography-Photo diode array detection

Residues of oxytetracycline, tetracycline and chlortetracycline in seafood products of Saudi Arabia were detected by using a simple, sensitive and rapid method via HPLC-PDA. The protein precipitation method that was used for sample extraction demonstrated high recoveries of OTC, TC and CTC. The limits of detection were 0.015 µg/g and 0.025,0.062 µg/g for all TCs in fish and shellfish, respectively. The limits of quantitation were 0.125 µg/g and 0.175 µg/g for all TCs in fish and shellfish, respectively. The method was precise and accurate since the RSD was less than 2%, while the % recovery was 95-105%. This study determined the occurrence of OTC, TC and CTC in seafood products that are sold in KSA's markets. The overall occurrence of these three medications in 249 seafood products was 24%(n = 60), while 15%(n = 37) exceeded the MRL. Thus, our recommendations are to enhance the monitoring of food production prior to marketing and to educate people regarding the proper disposal of antibiotics.

Residues of oxytetracycline in cultured rainbow trout

Nowadays, antibiotics are widely used in aquatic animals to control and treatment of infections or as food supplement for growth increase and animal output. With increasing use of veterinary drugs in food production, there is global consideration about the consumption of antimicrobial residues in aquatic foods and their effects on human health. This study was aimed to evaluate the Oxytetracycline (OTC) residues in Rainbow trout meat in Shahre-kord (Iran) markets before and after frying. After randomized collection of 50 samples of fish in Shahre-kord markets in a six months period were examined. The prepared samples were examined for OTC residues using HPLC analytical method before and after frying. Results showed that 3 (6%) of the samples before frying and 12 (24%) after frying were having lower than Maximum residual limits (MRLs) in Codex alimentarius. However, mean OTC residues before and after frying samples were above MRLs. The mean amounts of OTC were 2260 +/- 1090 and 1110 +/- 930 ng g(-1) before and after frying, respectively. These findings show that the frying of fish reduces OTC residual. Nevertheless, the usage of OTC should be reduced to an acceptable level in fishery industry.

A 5-kg time-resolved luminescence photometer with multiple excitation sources

A luminescence photometer was developed based on lanthanide-sensitized luminescence to detect environmental pollutants and residues in foods including, in particular, two classes of antibiotics: tetracyclines and fluoroquinolones. Multiple excitation sources, a xenon flashlamp and ultraviolet light-emitting diodes (UV LEDs), were used to their advantages. A photomultiplier tube module, gated to reject time-domain interferences, was used as a photodetector. Using danofloxacin as a model analyte, luminescence signal was linear in more than three decades (0.5-2000 ng/mL) with R(2) > 0.998 in each decade. This photometer achieved a limit of detection of 2.0 ng/mL with 1.3% average relative standard deviation. It is field deployable at 4.6 kg and 15 W power consumption.

Analytical strategies to determine antibiotic residues in fish

The accelerated growth of aquaculture has resulted in a series of harmful effects to human health. The widespread and unrestricted use of antibiotics in this industry, to prevent bacterial infections, leads to remaining amounts in the aquatic environment. This has resulted in the emergence of antibiotic-resistant bacteria in aquaculture environments, in the increase in antibiotic resistance in fish pathogens as well as in the transfer of these resistance determinants to human pathogens. Moreover, the use of large amounts of antibiotics may lead to the presence of residual antibiotics in fish tissue and fish products. Fluoroquinolones, tetracyclines, penicillins, sulphonamides and other antibiotics, exhibiting activity against both Gram-positive and Gram-negative bacteria, are widely used for the treatment and prevention of diseases in fish. An extended and comprehensive review on the recent analytical methodologies concerning antibiotic residues in fish reported in the literature is provided in the present article. Emphasis is given on sample preparation regarding isolation and purification, chromatographic conditions and method validation according to legislation. Results of published assays are comparatively presented and criticised.

Analysis of sulphonamide residues in edible animal products: A review

The methods of analysis for sulphonamide residues in edible animal products are reviewed. Sulphonamides are widely used for therapeutic and prophylactic purposes in both humans and animals, sometimes as growth promoters as additives in animal feed. As a result of their widespread use, there is concern about whether the levels used of these drugs can generate serious problems in human health, e.g., allergic or toxic reactions. Several methods for the determination of sulphonamides have been reported in the literature and this review considers high-performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC/MS), gas chromatography (GC), thin-layer chromatography (TLC), high-performance capillary electrophoresis (HPCE), enzyme-linked immunosorbant assay (ELISA), biosensor immunoassay (BIA) and microbiological methods. Specific aspects of analysing sulphonamides, such as sample handling, chromatographic conditions and detection methods are discussed. Methods for drug residue monitoring should be accurate, simple, economical in both time and cost, and capable of detecting residues below the maximum residue limits (MRL). The current sulphonamide detection technologies are based on chromatographic methods or bacteriological growth inhibition. The instrumental methods such as HPLC and GC are both sensitive and specific, but are laborious and expensive. Because of the labour-intensive processes, only a few cases of GC methods applied to residue analysis have been published. These methods are suitable for confirmation but not for screening of large numbers of samples. Microbiological methods do not require highly specialized and expensive equipment. They also use highly homogeneous cell populations for testing and thus result in better assay precision. Although HPCE has powerful separation ability, the precision is poor and the instrument still needs to be improved. To date, this technique has not been widely applied to routine analysis. Currently, TLC has been almost replaced by other instrumental analysis. A rapid, sensitive and specific assay is required to detect positive samples in routine analysis, which can then be confirmed for the presence of sulphonamides by HPLC. Immunochemical methods such as ELISA can be simple, rapid and cost-effective, with enough sensitivity and specificity to detect small molecules. This review can be considered as a basis for further research aimed at identifying the most efficient approaches.

A simplified LC–DAD method with an RP-C12 column for routine monitoring of three sulfonamides in edible calf and pig tissue

Use of an RP-C(12) analytical column with a mobile phase at pH 4.5 enabled excellent chromatographic separation and quantification of sulfadiazine (SDZ), sulfamerazine (SMR), and sulfamethazine (SMZ) in edible calf and pig tissue (muscle and liver). Tissue samples were extracted with acetonitrile, centrifuged without further clean-up, and analyzed by LC-DAD. The proposed conditions are useful for a rapid and reliable screening of the SDZ, SMR, and SMZ content of calf and pig tissue at concentrations lower than the maximum residue level (MRL) (LOQ between 27 and 55 ppb). Separation of some possible SMZ metabolites should be further investigated.

Electrocatalytic Tetracycline Oxidation at a Mixed-Valent Ruthenium Oxide−Ruthenium Cyanide-Modified Glassy Carbon Electrode and Determination of Tetracyclines by Liquid Chromatography with Electrochemical Detection

Mixed-valent films of ruthenium oxide-ruthenium cyanide were electrodeposited onto glassy carbon and characterized for the electrocatalytic oxidation of tetracycline. The currents produced by tetracycline were higher than from previously reported electrode modifications or pretreatments. In H(2)SO(4) pH 1.0 + 0.5 M K(2)SO(4), the second-order rate constant for the reaction between tetracycline and the Ru(III/IV) couple of ruthenium oxide was 3 x 10(5) +/- 1 x 10(5) mol(-1) cm(3) s(-1), and the rate of charge diffusion through the films was 4.5 x 10(-7) +/- 3.5 x 10(-7) cm(2) s(-1). Reaction was localized at the film-solution interface. When used as detectors in liquid chromatography (in H(3)PO(4) pH 2.5 + 0.1 M KH(2)PO(4) + 20% CH(3)CN, E = 1.10 V vs SCE), the electrodes gave limits of detection (>3 S/N) of 0.1 ppm for tetracycline and oxytetracycline and 0.5 ppm for doxycycline and chlorotetracycline. These limits were suitable for FDA and Codex Alimentarius guidelines for tetracyclines in food. Recoveries of the four tetracyclines from sea and freshwater shrimp were in the range 73-111%, which was higher or similar to the previously reported recoveries from shrimp.

Determination of quinolones and fluoroquinolones in fish tissue and seafood by high-performance liquid chromatography with electrospray ionisation tandem mass spectrometric detection

A reversed-phase high-performance liquid chromatographic method with tandem mass-spectrometric detection was developed and validated for the simultaneous analysis of eight quinolones and fluoroquinolones (oxolinic acid, flumequine, piromidic acid, enrofloxacin, ciprofloxacin, danofloxacin, sarafloxacin and orbifloxacin) in trout tissue, prawns and abalone. The analytes were extracted from homogenised tissue using acetonitrile and the extracts subjected to an automated two-stage solid-phase extraction process involving polymeric reversed-phase and anion-exchange cartridges. Good recoveries were obtained for all analytes and the limit of quantification was 5 microg/kg (10 microg/kg for ciprofloxacin). The limit of detection was 1-3 microg/kg, depending on the analyte and matrix. Confirmation of the identity of a residue was achieved by further tandem mass-spectrometric analysis. A procedure for estimating the uncertainty associated with the measurement is presented.

Analysis of quinolone residues in edible animal products

A comprehensive review on the analysis of quinolone antibacterials is presented. The review covers most of the methods described for the determination of quinolone residues in edible animal products. Sample handling, chromatographic conditions and detection methods have been discussed. A summary of the most relevant information about the analytical procedures has been included.