Lunch vendor seminar, November 5, 2009 (12:45–14:00)
New approaches to solving emerging food safety issues
Sponsored by 
THE BENEFITS OF HIGH RESOLUTION MASS SPECTROMETRY IN SCREENING ANALYSIS OF MYCOTOXINS IN FOOD
Michal Godula, Ph.D.
Thermo Fisher Scientific CZ, Prague, Czech Republic
michal.godula@thermofisher.com
Screening of pesticides, mycotoxins and veterinary drugs is of great importance in regulated environments such as food and animal feed analysis. Due to the broad variability of physico-chemical properties of the screened residues it is critical to employ very simple sample preparation procedure to maintain the recovery of the broad range of analytes. This however unavoidably leads to the fact that final extracts injected into the chromatographic system contain significant amounts of coextracts. For the chromatographic analysis it is therefore necessary to use the system with high selectivity but still capability to identify potential unknowns.
Traditionally these types of screening experiments have been carried out using SRM scanning with triple quadrupole instruments. This approach has certain limitations: (I) no post acquisition re-interrogation of data (II) limited number of compounds per analysis (III) little possibility to scan for unknown compounds at high levels. Because of these limitations, there is currently a trend towards full scan MS experiments in residue analysis. Current screening approaches employ high performance ToF instruments, with mass accuracies of < 5ppm and resolutions max 15,000, coupled to Ultra High Performance Liquid Chromatography (U-HPLC). However, most of the techniques and instruments currently available suffer from either poor mass accuracy and its variability and more significantly from resolution not sufficient to separate analytes of interest from coeluting species. Especially the mass resolution plays an important role in the successful identification of the most of present residues in samples containing high amounts of matrix coextracts.
The presentation will focus on the main problems and issues related to the application of the screening MS techniques using accurate mass technology and will introduce the new system based on the proven OrbitrapTM technology. Mass spectrometers based on the unique performance of this type of mass analyser are routinely achieving mass resolution up to 100,000 and mass accuracy below 2 ppm. Those parameters significantly improve the efficiency and accuracy of the residue screening methods and allow successful screening of various residues at even very low concentration levels. This fact will be documented on practical examples from the field of the analysis of priority mycotoxins in the samples of food and feed.
HIGH SENSITIVITY MULTI-RESIDUE PESTICIDE ANALYSES IN FOODS USING THE TSQ QUANTUM GC-MS/MS
Richard J. Fussell and Michael T. Hetmanski
Food and Environmental Research Agency, Sand Hutton, York, YO41 1LZ, UK
E-mail: richard.fussell@fera.gsi.gov.uk
GC-MS/MS was evaluated for the multi-residue analysis of approximately 100 pesticides in various matrices. Samples were extracted and cleaned-up using the QuEChERS procedure1. The samples were extracted with acetonitrile in the presence of magnesium sulfate, sodium chloride, disodium hydrogen citrate and trisodium citrate. Extracts were then cleaned-up by dispersive SPE using magnesium sulfate, and PSA.
A TSQ Quantum GC-MS/MS system was used for this study. The system comprised a Trace GC Ultra gas chromatograph equipped with a TriPlus autosampler interfaced with a TSQ Quantum triple quadrupole MS/MS detector operated in EI mode.
The pesticides evaluated included captafol, captan, chlorothalonil, dichlofluanid, dicofol folpet and tolylfluanid. These compounds have caused analytical problems, especially with GC-MS analyses of sample extracts produced by the QuEChERS procedure. The use of PTV, backflush and H-SRM (Highly-Selective Reaction Monitoring) techniques were also evaluated. The data from the optimized GC-MS/MS methodology was also directly compared to data derived from analysis of the same samples by “conventional” methodology (e.g. acetone or ethyl acetate-based extraction and single quadrupole GC-MS); to assess detection and quantitation limits, reproducibility and robustness for both analytical approaches.
QUICK AND AUTOMATED SCREENING METHOD FOR PRIORITY BETA-AGONISTS IN URINE
Thorsten Bernsmann, Ph.D.
Chemisches Landes- und Staatliches Veterinäruntersuchungsamt Münster (CVUA), Postfach 1980, 48007 Münster, Germany
β-agonists are synthetically produced compounds that, in addition to their bronchodilatory and tocolytic effects, can promote live weight gain in the food producing animals. There have been documented cases when consumption of liver and meat from animals illegally treated with clenbuterol has resulted in serious human intoxication1. Due to their adverse effects, the use of clenbuterol and its analogues from the beta-agonists group has been banned by the European Union2 and other regulatory agencies worldwide. Monitoring programs have shown that β-agonists are still illegally used by food producers, moreover, newly developed analogues with modified structures are being continuously introduced in routine practice. There is a clear need for quick and simple screening methods to routinely and accurately control levels of β-agonists in samples of animal origin (urine, plasma, tissues).
The current CVUA screening method for β-agonists in urine employs column clean-up and reconcentration before LC/MS determination. This is both expensive due to the use of molecularly imprinted polymer columns during sample preparation and laborious due to the need of fully trained laboratory staff. The LC/MS analysis is typically performed using a high performance ToF instrument, with mass accuracies of < 5ppm and resolutions of about 10,000 to 15,000, coupled to Ultra High Performance Liquid Chromatography (U-HPLC). However, most of the currently available ToF instruments suffer from resolution not sufficient to separate analytes of interest from potential coeluting species. The mass resolution plays a major role in the successful identification of most present residues in samples containing high amounts of matrix coextracts.
This presentation will describe a newly developed method based on a fully automated sample preparation procedure using the online TurboflowTM chromatography clean-up step and screening of priority β-agonists performed on a new system based on the proven OrbitrapTM technology. Mass spectrometers based on the unique performance of this type of mass analyser are routinely achieving mass resolution up to 100,000 and mass accuracy below 2 ppm.
The unique parameters of the Orbitrap based mass spectrometer together with quick and automated sample preparation using TurboflowTM technology significantly improved the throughput and efficiency screening method for β-agonists in urine samples.
- Botsoglou, N.A., Fletouris D.J., Drug Residues in Food. Pharmacology, Food Safety and Analysis, Marcel Dekker: New York, 2001
- EU COUNCIL DIRECTIVE 96/22/EC of 29 April 1996, OJ L 125, 23.5.1996
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