Spoonful of Honey: Xenobiotics with QuEChERS and UHPLC-Q-Orbitrap

Honey is a common sweetener and natural preservative with widespread usage. Unfortunately, honey bees face exposure to a wide variety of xenobiotics with potential to impact consumers. Sources for environmental pollutants include pesticide overspray as well as systemic pesticides found in soil, surface water, and water exudate from plants. Under some environmental conditions, honey bees are also prone to disease derived from exposure to bacteria, viruses, fungi, and parasitic mites. To control this, humans have used veterinary drugs and pesticides via treated feed or direct spray into hives, but these can persist in the honey, impacting food safety.

Li et al. (2016) recently evaluated ultra-high performance liquid chromatography-hybrid quadrupole-Orbitrap mass spectrometry (UHPLC-Q-Orbitrap MS) for the screening and identification of multiple xenobiotics in honey.¹ They applied a simple extraction process (QuEChERS) before UHPLC-Q-Orbitrap with a Q-Exactive Plus Hybrid Quadrupole-Orbitrap mass spectrometer (Thermo Scientific) operated in full scan-data-dependent MS/MS (full scan-ddMS2) mode plus parallel reaction monitoring (PRM). To make identifications, they relied on mass accuracy and retention time with the aid of an in-house accurate mass database (157 compounds: 105 pesticides, 49 antibiotics, three steroids) constructed for this purpose. They imported this database to TraceFinder software (Thermo Scientific) for rapid, efficient screening followed by quantitation using the acquired PRM data.

The research team grouped the analytes according to sensitivity and report the following:

Table: Xenobiotics Sensitivity

Group 1	≤2 µg/kg	70% of tested pesticides All antibiotics except tetracyclines and sodium nafcillin
Group 2	≥2 µg/kg and ≤5 µg/kg	Oxytetracycline and tetracycline
Group 3	≥5 µg/kg and ≤10 µg/kg	20% of tested pesticides Chlortetracycline, doxycycline, penicillin G, and sodium nafcillin
Group 4	≥10 µg/kg	10% of tested pesticides

The team validated both the screening and quantification techniques and report accuracy for all tested analytes in addition to enhanced sensitivity when compared with other methods. They indicate that the sensitivity acquired via Q Exactive PRM mode is “clearly superior” when compared with traditional methods (ESI-MS/MS), particularly given that the total running time for UHPLC-Q-Orbitrap clocked in under 15 minutes. They offer this study as the first to couple QuEChERS and UHPLC-Q-Orbitrap to screen and quantify xenobiotics in honey and propose the method’s potential utility for multi-xenobiotic screening in other matrices.
Reference

1 Li, Yi et al. (2016) ‘Hybrid quadrupole-orbitrap mass spectrometry analysis with accurate-mass database and parallel reaction monitoring for high-throughput screening and quantification of multi-xenobiotics in honey.’ Journal of Chromatography A, 1429: 119–126.