Dual ESI/APCI StayClean™ QSight LC-MS/MS for Analysis of Near 400 Polar and Non-polar Pesticide Residues in Tea

New Organic Monitoring Techniques
Oral Presentation

Prepared by S. Cai
PerkinElmer US, LLC, 2623 Las Mercedes Lane, Corona, CA, 92879, United States


Contact Information: [email protected]; 951-258-2470

ABSTRACT

Detecting pesticides in the environment and products we consume is becoming crucial. Pesticides are widely used in agriculture which could result in consumer exposure and negative health effects. Pesticides residues are commonly found in teas, and demand for analytical detection is increasing as global tea consumption increases. We developed a robust analytical method that enables almost 400 both polar and non-polar pesticides to be analyzed under ESI and APCI utilizing a dual source LC-MS/MS. This method eliminates the need for GC-MS/MS analysis by analyzing a list of 50 pesticides using APCI.

Experiments were carried out using a QSight 420 UHPLC-MS/MS via a divert valve. A simple solvent extraction sample prep procedure with internal standard dilution was employed. Matrix effects were evaluated using black tea, chamomile, and herbal blend. In total, 690 MRM transitions were monitored for 345 compounds in the ESI method, and 100 MRM transitions were monitored for 50 compounds in the APCI method. A single C18 column was used for both LC methods.

In this work, we demonstrate how a practical simple solvent extraction can be utilized to achieve the analysis of a large multi-residue panel of pesticides, with low limits of detection (with 319 of 395 analytes displaying LOQs of 5 ng/g or below), minimal matrix effects (94% of compounds with negligible %SSE in black tea), and excellent method performance (93% of compounds with accuracies within 70 - 120% and RSD < 20%). QSight’s dual source design allows for APCI analysis on traditionally GC only compounds to be included in this LC pesticide panel, reducing instrument workload, and potentially eliminating the need for complementary GC-MS protocol for multi-residue pesticide quantification. Simple sample preparation and reliable instrumentation allow for a robust analytical solution with the potential to analyze hundreds of pesticides in many different matrices.