High-throughput assay of rotenone in olive oil using atmospheric pressure chemical ionization tandem mass spectrometry

Simple on-site extraction and GC-MS analysis of rotenone and degradation products for monitoring invasive fish eradication treatments in fresh and brackish waters

The introduction of invasive fish species to aquatic ecosystems has been demonstrated to cause disastrous ecological effects. Current conservation strategies regard rotenone-containing piscicide formulations, such as commercial product CFT Legumine, as a potentially viable alternative to the cumbersome traditional approaches to fish eradication. This consideration relies on the fast degradation of rotenone and its relatively rapid dissipation from the environment. Piscicide treatments in fragile aquatic ecosystems should thus monitor not only rotenone concentrations following application, but also other byproducts and degradation products. We present a methodology for the analysis of rotenoids in fresh and brackish waters that addresses two main challenges: the accurate determination of applied concentrations in different salinity concentrations by performing a simplified on-site solid-phase extraction, overcoming the fast degradation of rotenone in sample storage conditions, and the selective analysis of rotenoid byproducts and degradation products by gas chromatography coupled to mass spectrometry. Limits of quantification were below the ecological no-effect concentration of rotenone (2 µg/L) and average recoveries exceeded 80%. Accuracy (compared to expected values) and precision (deviation of replicates) ranged from 78 to 103% and 3 to 14%, respectively, across various rotenoid concentrations. These metrics are more than satisfactory for the intended application of this simplified procedure. The method was applied to piscicide-treated samples, revealing significant and fast degradation of parent rotenoids in storage conditions, as well as a non-negligible accumulation of rotenone in the particulate fraction of water that could impact the effectivity of eradication efforts.

Identification and assay of carbohydrates in olive drupes by cesium attachment electrospray tandem mass spectrometry (ESI-MS/MS)

Identification and assay of sugars in olive drupes during their ripening phase is evaluated by tandem mass spectrometry. Recent achievements have shown that the quality of an extra virgin olive oil can be directly correlated to the ripening degree of the drupes that is likely linked to their saccharides content. An innovation in this peculiar food chain is now proposed that considers a high throughput assessment of the carbohydrate content by a recently introduced protocol based on the gas-phase chemistry of sugar-cesium adducts by ESI-MS/MS.

Review: multistage mass spectrometry in quality, safety and origin of foods

Quality and safety control and the validation of origin are hot issues in the production of food and its distribution, and are of primary concern to food and agriculture organization. Modern mass spectrometry (MS) provides unique, reliable and affordable methodologies to approach with a high degree of scientificity any problem which may be posed in this field. In this review the contribution of mass spectrometry to food analysis is presented aiming at providing clues on the fundamental role of the basic principles of gas-phase ion chemistry in applied research fields. Applications in proteomics, allergonomics, glycomics, metabolomics, lipidomics, food safety and traceability have been surveyed. The high level of specificity and sensitivity of the MS approach allows the characterization of food components and contaminants present at ultra-trace levels, providing a distinctive and safe validation of the products.

Isotope dilution method for the assay of rotenone in olive oil and river waters by liquid chromatography/multiple reaction monitoring tandem mass spectrometry

A new approach for the assay of rotenone (1) by isotope dilution mass spectrometry is presented. The extreme toxicity of rotenone, a natural phytodrug with insecticidal and piscicidal activity, recently banned by national and international environmental protection agencies, calls for the development of sensitive and accurate methods of analyses. Accordingly, the proposed protocol is based on the availability of the labeled internal standard rotenone-d3 (3) which can be conveniently prepared by consecutive and specific mono-O-demethylation, and remethylation with methyl iodide-d3. The sensitivity of the method is confirmed by the very low limit of detection (LOD) and quantitation (LOQ) values achieved in the assay of 1 in two distinct fortified matrices, and is further supported by the observed accuracy values.

Persistence and effects of rotenone on oil quality in two Italian olive cultivars

The aims of this work are to assess the persistence of rotenone in oil and drupes of olive plants of cultivars Nocellara del Belice (NB) and Cassanese (CA), and to compare the quality of oils from rotenone-treated and untreated plants. Samples of drupes and oil were analyzed at 2, 12, 22 and 30 days after treatment. Rotenone levels in drupes of treated plants declined by about 50% after 22 days from treatment (0.037 mg kg(-1) in NB and 0.039 mg kg(-1) in CA), whereas the respective values in the oil were higher (0.209 mg kg(-1) in NB and 0.229 mg kg(-1) in CA) and had a lower decay half-life (4.02 days in NB and 4.71 days in CA). For both cultivars, no significant differences in oil physicochemical and nutritional parameters were found between the two treatments. The panel test of oils extracted after 22 days did not reveal significant differences in unpleasant aromatic notes nor defects between the two treatments. Our results confirm that serious doubts remain about the safety and healthiness of oils extracted from drupes treated with rotenone. This information could assess the real risk in the use of this product for plant protection in olive growing.

Assay of rotenone in river water by high-throughput tandem mass spectrometry and multiple-reaction monitoring methodology

The high-throughput analytical approach proposed for the assay of rotenone in lake and river waters presented here is based on atmospheric pressure chemical ionization (APCI) multiple-reaction monitoring (MRM) methodology whereby the analyte and internal standard solutions are directly analyzed, without any previous chromatographic separation. The very good accuracy is obtained by the critical choice of a reference compound that shows gas-phase chemistry similar to that of the analyte, by producing the same product ions selected for the MRM-based assay.