Assay of ochratoxin A in grape by high-pressure liquid chromatography coupled on line with an ESI-mass spectrometry.
In this paper, we propose a method for detection of ochratoxin A (OTA) in grapes by using nano-reversed-phase high-performance liquid chromatography-electrospray ionization-mass spectrometry (nano-RP-HPLC-ESI-MS). The method is rapid, highly sensitive and reproducible. OTA is extracted preferably from the entire acinus, rather than must; using chloroform at long incubation time period, lyophilized, resolubilized in acetonitrile (AcCN) and injected onto a reversed phase capillary or analytical column. Capillary columns are the method of choice because it requires a reduced amount of injected sample and consequently the chloroform necessary for OTA extraction, which is a toxic agent. This method gives a detection limit of femtog/ml, without resorting to an immunoaffinity clean-up or concentration, which makes it by far superior to any other method reported. Moreover, by using MS as a detection method it is possible, in the case of a complex matrix, to measure its molecular mass and to confirm the presence of OTA by MS-MS, which cannot be done by fluorescent detection. The method has a high sample extraction throughput (24/h) and has adequate precision (between batch C.V. <8%) and sensitivity (limit of detection (LOD)=1 pg/g; limits of quantification (LOQ)=2 pg/g) for OTA measured.
Timperio
Anna Maria
AM
Department of Environmental Sciences, University of Tuscia, 01100 Viterbo, Italy.
Magro
Paolo
P
Chilosi
Gabriele
G
Zolla
Lello
L
D002846:Chromatography, Affinity / Q000379:methods; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D036103:Nanotechnology; D009793:Ochratoxins / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D027843:Vitis / Q000737:chemistry*
D009793:Ochratoxins; C025589:ochratoxin A