Method validation and risk assessment for sulfonamides and tetracyclines in bees' honey from Egypt, Libya and Saudi Arabia

Several studies worldwide have reported contamination of bees' honey by antibiotics, which may pose a hazard to consumers' health. The present study was thus established to: (1) introduce a validated multi-residue method for determining sulfonamides (SAs) and tetracyclines (TCs) in honey; and (2) characterize the potential risk due to the exposure to SAs and TCs in honey samples from Egypt, Libya, and Saudi Arabia. SAs and TCs were simultaneously extracted using solid-phase extraction and matrix solid phase dispersion methods. SAs and TCs were screened using HPLC-MS/MS and HPLC-DAD. The results confirmed detection limits for SAs and TCs by HPLC-MS/MS of 0.01 and 0.02-0.04 (ng g^-1), respectively. The limits were 2.5-5.6 and 12.0-21.0 (ng g^-1) for SAs and TCs by HPLC-DAD, respectively. The obtained accuracy rates were in the ranges of 83.07-86.93% and 86.90-91.19%, respectively, for SAs and TCs, with precision rates lower than 9.54%. Concerning the occurrence of antibiotics, the positive samples constituted 57.6%, 75%, and 77.7% of the Egyptian, Saudi Arabian, and Libyan samples, respectively. Notably, SAs antibiotics were the most prevalent in the Egyptian and Saudi Arabian samples; in contrast, TCs were the most dominant in Libya. Calculated parameters of risk assessment, concerning the aggregated exposure to SAs and TCs, showed no potential adverse effects from the exposure to contaminated honey in studied countries.

A chitosan solution-based vortex-forced matrix solid phase dispersion method for the extraction and determination of four bioactive constituents from Ligustri Lucidi Fructus by high performance liquid chromatography

A simple and efficient sample preparation method to extract four bioactive compounds (echinacoside, specnuezhenide, oleuropein and nuezhenoside G13) from Ligustri Lucidi Fructus was established by vortex-forced matrix solid phase dispersion (VFMSPD) method. Chitosan solution was applied as green eluent in this procedure and Celite AZO was employed as dispersant. High performance liquid chromatography (HPLC) equipped with ultraviolet (UV) detector was used to analyze the target analytes. The best result of the investigation was obtained with Celite AZO as dispersant, sample/ dispersant ratio as 1:1, grinding for 2 min, 1 mL high-viscosity chitosan solution (0.5 mg mL^-1) used as the elution reagent and vortex mixing for 1.5 min. The method exhibit a good linearity for the analytes (r² > 0.999). The absolute recoveries of the four target compounds in Ligustri Lucidi Fructus ranged from 90.7% to 98.8% and the relative recoveries of the target compounds ranged from 99.2% to 102% (RSD ≤ 3.4%), which were obtained by the final optimization method. Consequently, the newly developed chitosan solution-based vortex-forced matrix solid phase dispersion (MSPD) combined with HPLC could be efficiently applied to extract and analyze the target compounds in Ligustri Lucidi Fructus samples.

Rapid Detection of the Antibiotic Sulfamethazine in Pig Body Fluids by Paper Spray Mass Spectrometry

We report herein a practical method for nonlethal detection of the antibiotic sulfamethazine in pig body fluids via the combination of simple extraction and paper spray mass spectrometry (PS-MS). This method requires minimal sample preparation while still providing high sensitivities and accuracies in complex matrices including pig whole blood (LOD = 7.9 μg/L; recovery = 95.4-103.7%), pig serum (LOD = 11.5 μg/L; recovery = 103.2-106.2%), and synthetic urine (LOD = 11.2 μg/L; recovery = 99.1-103.2%). Given a known correlation between the level of sulfamethazine in body fluids and edible tissues, this method shows great promise as a practical and nonlethal solution for rapid testing of the drug, which can substantially aid managerial decision in the livestock industry.

Simplified miniaturized ultrasound-assisted matrix solid phase dispersion extraction and high performance liquid chromatographic determination of seven flavonoids in citrus fruit juice and human fluid samples: hesperetin and naringenin as biomarkers

In the present study, for the first time, a simplified miniaturized ultrasound-assisted matrix solid-phase dispersion (SM-USA-MSPD) method with a different application for liquid matrices was developed to extract different flavonoids (hesperidin, diosmin, eriocitrin, narirutin, naringin, hesperetin and naringenin) from citrus fruit juice and human fluid samples prior to their determination using high performance liquid chromatography (HPLC). Different effective parameters were studied and under the optimum conditions (including sample volume: 150μL; solid phase: silica-based C18, 200mg; eluting solvent: methanol, 500μL; pH: 4; and sonication: 6min; at room temperature), limits of detection and limits of quantification were ranged from 23.3 to 46.8ngmL(-1) and 74.8 to 141.5ngmL(-1), respectively. Once optimized, analytical performance of the method was studied in terms of linearity (0.074-198.5μgmL(-1), r(2)>0.991), accuracy (recovery=84.6-101.5%), and precision (repeatability: intra-day precision<5.9%, and inter-day precision<7.2%). At the end, SM-USA-MSPD method was successfully applied to estimate the levels of hesperetin and naringenin in plasma and urinary excretion -after ingestion of orange, grapefruit and lime juices- and the obtained results confirmed that these compounds could be used as good biomarkers of citrus fruit juice intake.