RAFA 2009: Bruker Seminar

EU projects represented at RAFA 2009:

Lunch vendor seminar, November 5, 2009 (12:45–14:00)

Rapid Methods for Food Control Based on Proven ESI-(UHR)-TOF Technology (micrOTOF, maXis) and New Generation of High-Sensitivity Ion Trap (amaZon)

Sponsored by

Multi-Target Screening of Several Hundred Pesticides in a Single LC/MS Run by Exacted Ion Traces using ESI-(Q)TOF or UHR-TOF Technology

Rob van der Heijden¹, Arnd Ingendoh², Petra Decker², Carsten Baessmann², Marcus Macht², Romano Hebeler²
¹ Bruker Daltonics BV, Wormer, The Netherlands; rob.vanderheijden@bruker.nl
² Bruker Daltonik GmbH, Bremen, Germany

The usefulness of LC/MS/MS methods for the unambiguous identification and quantification of pesticides in complex matrix samples are well known. Triple quadrupole systems have proven to be useful for this task due to their high specificity in MS/MS mode and their low detection limits. However, working in MS/MS mode makes any MS system blind for all other compounds than the current MS/MS transition is designed for. Therefore, it is difficult to develop methods for simultaneous analysis of high numbers of pesticides. Thus, other ways of achieving specificity are of interest, such as the high mass accuracy and mass resolution of an ESI-(Q)TOF system or even UHR-TOF system. It can generate high specificity without limiting the number of simultaneously observed target compounds.

The ESI-TOF MS approach in general enables the screening for several hundred of possible pesticides within one run. The selectivity is based on the accurate mass, with mass traces defined within 0.002 Da over a dynamic range of about 4 orders of magnitude. By using a database of several hundred pesticides, spiked samples can be easily detected. Sensitivity in the range of low ppb range or even below can be achieved. Results for various matrices will be presented and discussed for potential need of sample preparation. An excellent linear range of 4 orders of magnitude is achieved, allowing the quantitation of the pesticides. In contrast to classical screening approaches by triple quadrupole instruments there are several benefits:

A high number of targets can be screened at the same time without loss of sensitivity
Unknown peaks can be identified based on accurate mass and true isotopic pattern
Data can be reprocessed later for additional compounds (archiving)
Profiling of the data allow for further statistical data evaluation.

Benefits and requirements of the method will be discussed in detail.

Rapid Methods for Food Control Based on Novel Generation of High-Sensitivity Ion Trap Bruker AmaZon

L.J. Fremlin¹, M. Pelzing¹, A. Ingendoh²
¹ Bruker Daltonics Division, Preston, Australia; rob.vanderheijden@bruker.nl
² Bruker Daltonk GmbH, Bremen, Germany

Ion traps have been shown only limited use so far in quantitation studies. Main reason was an unsufficiently high RSD on low sample amounts in matrix loaded samples. However, with recent improvements in ion trap trap technologiy with regard to ion transmission, ion storage capacity and data acquisition rate, ion traps show a much improved LLQ for many applications.

E.g., adulteration of food and beverages with industrial chemicals has become an issue of late, as evidenced in September 2008 with the contamination of infant milk formula in China with melamine. There is a requirement for rapid and sensitive methods to detect and quantify such chemicals in complete matrices. LC-MSMS methods are superior to GC-MS methods in that they have an easy sample preparation and do not require sample derivatization. The high capacity ion trap mass spectrometer is a highly robust system capable of operating in full scan, MSn and MRM modes. Here we report a recently developed method for the extraction, detection, and quantitation of melamine, cyanuric acid residues and other unwanted food stuff.

Chromatographic separations were carried out using a Dionex UltiMate 3000 using an Acclaim Mixed-Mode WAX-1 (Dionex, Sunnyvale, CA, USA) column (2.1 x 150 mm, 5µm) maintained at 30 °C and operated in a HILIC mode. For the simultaneous detection of melamine and cyanuric acid the mobile phase gradient consisted of water / 0.1% formic acid (10%) and acetonitrile (90%) to 50%:50% over two minutes before returning to initial conditions at a flow rate of 300 µL/min, and a run time of five minutes. 10 µL injections were made. The ion-trap mass spectrometer was optimized for the detection of melamine in MRM mode.

Using the novel high capacity ion trap mass spectrometer it was possible to establish a calibration curve for melamine ranging from 1 to 1000ppb.. Melamine was spiked into infant milk formula (1 ppm and 2.5 ppm) and extracted as per the conditions above. Despite the low detection limits, these concentrations were chosen on the basis of infant milk contamination recommendations by the FDA. Furthermore, it was possible to detect and quantify melamine contamination in a number of samples of contaminated infant milk power from China well above the limits determined by the FDA.