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An ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) based multiclass multi-residue method for the simultaneous analysis of 5 polyether ionophores, 4 tetracycline and 10 sulfonamides in animal and aquaculture fish tissues was developed and validated. Sample extraction and clean-up were based on a modified QuEChERS method. The method was validated using an in-house validation based on performance characteristics modified from Commission Decision 2002/657/EC. Both matrix effect and uncertainties associated with sample preparation and instrumental analysis were minimised by the use of matrix-matched calibrations. Recoveries of analytes were generally satisfactory and typically fell between 80% and 113%. The repeatability and intermediate reproducibility measured as relative standard deviations were in most cases less than 15% (n = 63). The decision limit (CCα) and detection capability (CCβ) ranged from 110.7 to 125.8 and 121.5 to 151.7 µg kg−1 for tetracyclines, 113.4 to 118.3 and 116.8 to 126.5 µg kg−1 for sulfonamides and 50.8 to 52.4 and 51.5 to 55.6 µg kg−1 for polyether ionophores, respectively. The method displayed its fitness for purpose through satisfactory results obtained in international proficiency testing schemes. The method was applied to animal and aquaculture fish tissues obtained from different sources in South Africa. Polyether ionophores were predominantly detected in samples in the range 4.26–290.10 µg/kg. Oxytetracycline was found in one porcine liver sample; however, none of the targeted analytes were present above the detection limit in the aquaculture samples. [ABSTRACT FROM AUTHOR]

Globally, tea is the second most consumed drink next to water as it is considered healthy with is medicinal properties. A total of 100 tea samples obtained from registered shops within South Africa were extracted using a validated QuEChERS extraction method followed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) analysis. The suitability of the analytical method for all the analyzed mycotoxins was determined based on the recoveries (which ranged from 100 to 117%), linearity (>0.99), precision (6–29%) among other satisfactory performance characteristics. The results revealed that three of the aflatoxins i.e., AFB 1 , AFB 2 , AFG 2 , ochratoxin A (OTA) and zearalelone (ZEA) were not detected in all the samples analyzed, nonetheless AFG 1 was detected at low concentrations (1.72–5.19 μg/kg), which were below the levels regulated in food by the EU Commission Regulation 1881/2006. The low contamination profile of mycotoxins in tea necessitates their continuous monitoring to ensure product safety. Nonetheless, since this is the first study of mycotoxin contamination of teas in South Africa, it is thus essential to conduct more studies on diverse kinds of tea for mycotoxins regulation in the country. • Rooibos a popular tea found in South Africa. • This study were subjected for 6 mycotoxins using UHPLC-MS/MS. • The low profile of mycotoxins in tea necessitates their continuous monitoring. • There is need for safety and quality control of teas in South Africa. [ABSTRACT FROM AUTHOR]

Background and Aims The thiol compounds, 3-mercaptohexan-1-ol ( 3MH) and 3-mercaptohexyl acetate ( 3MHA), are important, pleasant volatile thiols conferring fruity notes in wines. The analytical determination of these thiols in wine remains problematic due to their trace concentration and instability. The main aim of this study was to develop a liquid/liquid extraction and ultra-performance liquid chromatography tandem mass spectrometry ( UPLC- MS/ MS) method for the determination of 3MH and 3MHA concentration in Sauvignon Blanc wines. Methods and Results A novel sample preparation based on a liquid/liquid extraction was developed. Thiols were quantified by UPLC- MS/ MS after derivatisation with o-phthaldialdehyde. Good results were obtained with the method in terms of limit of detection and of quantification, accuracy and repeatability. Average concentration of 3MH in 18 South African wines was 1320 and of 3MHA 313 ng/L. Conclusions The analytical method described enables the liquid/liquid extraction of 3MH and 3MHA from wine, separates them by liquid chromatography and detects them by MS/ MS at a concentration lower than that of their sensory threshold. Significance of the Study The determination of the concentration of 3MH and 3MHA in Sauvignon Blanc wines could enable wine producers to predict the sensory attributes of the wine. [ABSTRACT FROM AUTHOR]

Senecio coronatus (known as izonkozonko and ubulibazi in Zulu) is commonly used in traditional medicine in South Africa as purification purgative and enemas for infants during weaning. We show for the first time that this species does not contain pyrrolizidine alkaloids and that reported cases of fatal hepatic sinusoidal obstruction syndrome in infants were caused by wrongly identified Senecio species containing large amounts of retrorsine-N-oxide. A validated ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the detection and quantitation of pyrrolizidine alkaloids is described. [ABSTRACT FROM AUTHOR]

Fungal species recovered from fermented foods and beverage from Nigeria and South Africa were studied to establish their toxigenic potential in producing an array of secondary metabolites including mycotoxins ( n = 49) that could compromise human and animal safety. In total, 385 fungal isolates were grown on solidified yeast extract sucrose agar. Their metabolites were extracted and analyzed via ultra-performance liquid chromatography tandem mass spectrometry. To examine the grouping of isolates and co-occurrence of metabolites, hierarchal clustering and pairwise association analysis was performed. Of the 385 fungal strains tested, over 41% were toxigenic producing different mycotoxins. A. flavus and A. parasiticus strains were the principal producers of aflatoxin B₁ (27⁻7406 µg/kg). Aflatoxin B₁ and cyclopiazonic acid had a positive association. Ochratoxin A was produced by 67% of the A. niger strains in the range of 28⁻1302 µg/kg. The sterigmatocystin producers found were A. versicolor ( n = 12), A. amstelodami ( n = 4), and A. sydowii ( n = 6). Apart from P. chrysogenum, none of the Penicillium spp. produced roquefortine C. Amongst the Fusarium strains tested, F. verticillioides produced fumonisin B₁ (range: 77⁻218 µg/kg) meanwhile low levels of deoxynivalenol were observed. The production of multiple metabolites by single fungal species was also evident.