Rapid Characterization of Pesticides Spiked in Apple Juice using DART®-MS of Juice

Authors: Jordan Krechmer, Elizabeth Crawford, Brian Musselman
2010, Sep, 06

 

Content Data and Images

 

Open Air Desorption Ionization of Apple Juice

DART®-MS analysis of Apple Juice is facilitated by using Experiment modules that position samples in the desorption ionization region of the DART® source

Samples can either be quickly inserted into the desorption ionization region using an automated X-Y sample positioning stage

Individual aliquots of juice or extract are positioned on separately addressable glass inserts to facilitate more reproducible analysis

The DART® SVP control software controls the type of movement, gas temperature, ionization mode, and exposure time for the experiment

48-Well Plate with Inverted Glass Inserts

• Sampling using the 3+D scanner module.
• Microtiter plate populated with glass inserts in every other row
• Up to 10 ul of a liquid samples can be pipetted onto the top surface of the glass inserts
• One glass insert per sample isolates each sample from the next so that each analysis starts with the same temperature surface
• The Angle DART® SVP option is used for more efficient desorption
• VAPUR® is used to permit sampling from the furthest position on the plate

APPLE JUICE, DART®-MS

• 10 ul of Apple Juice applied to top of insert.
• Carbohydrate related ions present and
dominate the positive ion mass spectrum
• Few ions detected in the negative ion mass spectrum
• Analysis complete in 10 seconds per sample using automated positioning with the 3+D Scanner

3+D Scanner, Analyzing a Pesticide Mixture

• Pesticide Mix
• Contained 140 pesticides
• Most of the pesticide standards were obtained from the U.S. EPA Pesticide Repository (Ft. Meade, MD), whereas others were obtained through Fluka/Sigma Aldrich (St. Louis, MO), Wako Chemicals USA (Richmond, VA),Honeywell Riedel-de Haën (Seelze, Germany), and EQ Laboratories, (Atlanta, GA).

Pesticide Standards in Apple Juice

Positive ion DART®-MS mass chromatograms for three of the major protonated pesticides detected in 20 replicate analysis and undetected in 4 control samples

Negative ion DART®-MS mass chromatograms for three of the major pesticides detected in 20 replicate analysis and undetected in 4 control samples