Screening and Quantitation of 200+ Pesticides in Honey by an Integrated On-Line Extraction UHPLC-MS/MS System

Zicheng Yang and Louis Maljers, Bruker Daltonics Inc.
Poster presented as part of NACRW 2015 Conference, St. Petersburg, FL., 19-22 July 2015.

Introduction

Solid Phase Extraction (SPE) is widely used for sample clean up before LC-MS/MS analysis. It is costly and time consuming. Here we present a simple, cost effective and sensitive procedure for screening and quantitation of pesticides in honey using the Thomson eXtreme|FV® for sample clean-up and the Bruker integrated On-Line Extraction (OLE)-UHPLC-MS/MS system for analysis of pesticides in honey.

A study using the EVOQ analyzed 200+ pesticides in honey using only one method with positive negative switching for 430 MRM transitions. The measurements were conducted by dilute-and-shoot without sample enrichment using the Thomson eXtreme|FV. The honey was diluted 10-fold and filtered with 0.2um PVDF eXtreme|FV prior to injection. An YMC-Pack ODS-AQ, 10 µm, 10 mm x 2 mm (I.D.) column was used as trap column. An aqueous mobile phase was used to retain the pesticides on the trap column and to elute the monosaccharides in the honey out to the waste followed by a valve switch to couple the trap column with analytical column for separation and detection. The linear range was approximately 1ng/g to 1000ng/g and the linear regression co-efficiency R² was >0.99.

Equipment

UHPLC Conditions

  • Trap Column: YMC-Pack ODS-AQ, 10 µm, 10 mm x 3.0 mm I.D.
  • Mobile Phase C: 5mM Ammonium Fluoride (AF) in water
  • Equilibration flow: 1000µL (3.0 min)
  • Loading Flow: 600 µL
  • Analytical Column: YMC-Pack ODS AQ, 3 µm, 150 mm × 3.0 mm (I.D.)
  • Column Temperature: 40˚C
honey OLE valves config
  • Injection Volume: 50µL
  • Mobile Phase A: 5mM Ammonium Fluoride in Water
  • Mobile Phase B: 100% MeOHM

LC Gradient

Time (min)Mobile Phase A (%)Mobile Phase B (%)Flow Rate (µL/min)
0.09010400
0.29010400
2.03070400
6.52080400
8.00100400
15.00100400
15.19010400
18.09010400
  • OLE Valves Configuration
  • EVOQ Conditions

Source parameters

Source: HESI
Spray Voltage (+/-)4000V
Cone Gas Flow20
Cone Temperature250˚C
Heated Probe Gas Flow45
Heated Probe Temperature400˚C
Nebulizer Gas Flow65
Exhaust Gas On

Sample Preparation

  • Weigh about 50mg of honey in the Thomson eXtreme|FV (p/n 85531).
  • Add MeOH/Water, 50/50, v/v make 100 mg/mL solution.
  • Mix by pipet and depress the filter vial plunger, 0.2 µm PVDF completely to filter.
  • Solution is ready for injection.

Results

Store bought honey samples analyzed by UHPLC-MS/MS in a 200+ pesticide panel utilizing nine point calibration curves for the individual pesticides, see Fig. 1. Simple sample prep was achieved using the Thomson eXtreme Filter Vial, 0.2um PVDF using a simple dilute – filter – shoot. High concentration of sugars were removed utilizing the trap column without getting into MS system. Excellent linearity was achieved from 0.01ng/mL to 100ng/mL. The LOQ was determined to be 0.1ng/ml for 158 pesticides and <0.01ng/mL for 57 pesticides. The LOD was determined to be <0.1ppb. Good retention time distribution and auto-calculating scan times for each individual pesticide was used for single run for both +/- pesticides with hundreds of MRM transitions. No peak shape change by injecting 50 µL solution containing 50% MeOH. High organic in sample solution helps to reduce pesticides binding to the eXtreme|FV. Fifteen pesticides were detected in store bought honey from different countries, see Table 2. High levels for Fenpyroximate was detected in US sourced honey.

honey mass spec pesticide MRM

table.1Example of Mass Spec Pesticide MRM Set-up

honey timed MRM windows for 215 pesticides

fig.1Timed MRM Windows for 215 Pesticides

Table.2Store bought honey from the US (3 different brands), Canada, China and India were analyzed for Pesticides analyzed in this method. Test result (ND= not detected or < 0.1ppb)
Honey SourceIndiaCanadaChinaUS-1US-2US-3
PesticidesConcentration in ng/g
AcetamipridNDND0.64NDNDND
BoscalidND17.5NDND0.153.38
CarbarylND0.71NDNDNDND
DioxacarbNDNDNDND1.352
FenpyroximateNDNDNDND0.2655
FludioxinilND1.49NDNDNDND
FluometuronNDNDNDNDND2.8
HexaythiazoxNDND0.16NDNDND
MCPAND0.68NDNDNDND
MetalaxylND0.1NDNDNDND
MethoxyfenozideNDNDNDNDND0.94
PicoxystrobinND4.23NDNDNDND
Piperonyl butoxideND0.26ND0.570.760.21
PropargiteND0.32ND0.1NDND
ThiamethoxamND4.88NDNDNDND

Conclusion

  • Bruker UHPLC combined with the EVOQ Elite Triple Quadrupole MS was used for identification and quantification of 200+ pesticides in store-bought honey sourced from different countries utilizing the Thomson eXtreme|FV, 0.2um PVDF
  • Method is simple, sensitive, and ease of use and single run for positive and negative pesticides
  • Simple sample prep consisting of diluting the sample, filtering and injecting onto the UHPLC-MS/MS achieved LOQ of < 0.01ng/mL for 158 pesticides and 0.1ng/mL for 57 pesticides
  • Bruker Advance UHPLC with OLE coupled to EVOQ LC-QQQ provides a more convenient and simpler approach than SPE to analyze pesticides in honey
5

fig.1Examples of 9 point calibration curves.

honey chromatograms

fig.2Chromatograms of pesticides spiked into honey, USA-1.

Title

Screening and Quantitation of 200+ Pesticides in Honey by an Integrated On-Line Extraction UHPLC-MS/MS System

Description

[A] simple, cost effective and sensitive procedure for screening and quantitation of pesticides in honey using the Thomson eXtreme|Filter Vials for sample clean-up[.]

PDF Application

Product Used in Application

eXtreme|FV® - PVDF 0.2µm

eXtreme|FV® - PVDF 0.2µm

Pre-Split Septum, Red Cap

pn#85531-200

Related Products

© 2021 Thomson |
Solutions At Work™

LinkedIn