Defra - Department for Environment, Food and Rural Affairs.

Science Search

Science and Research Projects

Return to Science Search homepage   Return to Project List

Development of multi-residue methods for the analysis of pesticides in herbs and spices - PS2524

Description
Each year laboratories contributing to the Pesticide Residues Committee (PRC) monitoring programme to screen up to 4000 samples for a targeted list of pesticides in a range of commodity types. There have been PRC surveys carried out on fresh herbs in 1995 and 2002, and in the most recent survey the commodities analysed were basil, coriander and parsley. There has been no UK monitoring data on dried herbs and spices, as these present much greater analytical difficulty due to the much higher proportion of dry matter (and co-extractives) compared to e.g. fruit and vegetable samples. Therefore validated, robust methods are required for analysis of dried herbs and spices to enable monitoring and risk assessment work to be carried out. This is envisaged to be of increasing significance in the near future as consumption of “ethnic” food increases in Europe. At present there is considerable concern about contamination of spices by Sudan and other azo dyes, the situation regarding contamination by pesticides is unknown due to the lack of data.

There are no current UK or EU MRLs for spices, although there are proposed EU MRLs of 0.5 mg/kg for ethofumosate and metabolites in cumin, juniper, nutmeg, pepper, vanilla and other spices. At present Codex MRLs exist only for bromide ion and hydrogen phosphide in spices. However, at the Joint FAO/WHO Meeting on Pesticide Residues (JMPR) in 2004 (Rome, 20-29 September 2004) MRLs were recommended for the different spice sub-groups (eg seeds, fruits /berries and roots/rhizomes) for a range of 28 pesticides (mostly organophosphorus) and a separate suite of 50 pesticides applicable just to dried chilli peppers.

In some herb and spice producing countries such as India, analyses for organochlorine, organophosphorus and synthetic pyrethroid pesticides are carried out for quality control purposes (http://www.indianspices.com). Indian guidelines for exporters refer to US FDA Tolerance Limits for a limited range of organochlorine, organophosphorus and synthetic pyrethroid pesticides in pepper, dried ginger, cumin and fennel. The relative lack of MRLs currently applicable to dried herbs and spices is due to analytical difficulties with these commodities, and thus a lack of validated, robust methods to enforce any statutory limits. It is likely that more pesticides may have MRLs applicable to dried herbs and spices in the future, especially if reliable analytical methods become available. To date there has been a limited amount of data on the occurrence of organochlorine and organophosphorus pesticides in spices available in the literature (Manirakiza et al, (2000); Abou-Arab and Abou Donia (2001)).

The proposal is to evaluate recently developed rapid multi-residue methodology based on the Quechers procedure together with GC-MS and LC-MS/MS for the analysis of a suite of pesticides (including carbendazim, methamidophos, methomyl, monocrotophos and procymidone as requested by PSD) in chilli powder and curry powder. A preliminary CSL evaluation of GC-MS/MS for selected herbs and spices gave promising results, indicating a good probability of success.

The suite of pesticides could also include; ethofumosate (proposed EU MRL); acephate, azinphos-methyl, chlorpyrifos, chlorpyrifos-methyl, cypermethrin, diazinon, dichlorvos, dicofol, dimethoate, endosulphan [total], ethion, fenitrothion, iprodione, malathion, metalaxyl, mevinphos, parathion, parathion-methyl, permethrin, phenthoate, phorate, phosalone, pirimicarb, pirimiphos-methyl, quintozene, vinclozolin (all recommended for Codex MRLs by JMPR, based on non-UK monitoring data); DDT, HCH, HCB, heptachlor, alachlor, aldrin, methoxychlor, profenophos (residues in spices reported in the literature).

Analysis for ethylene oxide and the reaction product ethylene chlorohydrin requires separate specialised methods, eg. using hydrolysis followed by chlorination, headspace analysis or specialised GC columns; and thus can not be included in any multi-residue methodology.


Objective
The proposal is to evaluate recently developed rapid multi-residue methodology based on the QuEChERS procedure [1] together with GC-MS and LC-MS/MS for the analysis of a suite of pesticides including; carbendazim, methomyl, methamidophos, monocrotophos and procymidone as requested by PSD, in chilli powder and curry powder.

The recently developed Quechers rapid multi-residue methodology has already been successfully applied to other dried commodities such as wheat and rice [2], thus it is proposed to extend this methodology to the analysis of chilli powder and curry powder.

In recent years there has been considerable improvement in the performance and sensitivity of LC-MS/MS detection, and the use of recently available tandem quadrupole GC-MS/MS used in the multiple reaction monitoring (MRM) transition mode has been shown to offer increased sensitivity and selectivity compared to detection using single quadrupole MS instruments operated in selected ion monitoring (SIM) mode [3]. Thus the use of these improved detection techniques offer the possibility of detection of low level residues of pesticides in dried herb and spice commodities. The use of large volume injection GC-MS/MS has already been applied to analysis of infant foods (PS 2517), and could be used to increase overall sensitivity, provided the extracts are sufficiently clean and do not degrade the chromatographic integrity of the system. Preliminary CSL evaluations of GC-MS/MS for selected herbs and spices gave promising results, indicating a good probability of success.

The use of difficult matrix introduction GC-MS (DMI GC-MSD) offers an alternative approach where pesticides can be separated from non-volatile co-extractives during sample introduction into the GC system. The likelihood of success of this technique is dependent on extractives from herb and spice matrices being much less volatile than the analytes of interest.

Analysis for ethylene oxide and the derived product 2-chloro-ethanol (ethylene chlorohydrin) requires separate specialised methodology and thus this compound cannot be included in any multi-residue method.


Specific objectives are:

1) To optimise GC-MS and LC-MS for the determination of specified pesticides of interest, and then carry out an initial evaluation of extraction and clean-up techniques for the analysis of these pesticides in chilli powder and curry powder; on basis of evaluation to decide on the overall analytical approach to be used, by 31/01/06.

2) To attempt to validate the selected pesticides including carbendazim, methomyl, methamidophos, monocrotophos and procymidone in chilli powder and curry powder at a target level of 0.5 mg/kg by 31/03/06.
Project Documents
• Final Report : Development of multi-residue methods for the analysis of pesticides in herbs and spices   (108k)
Time-Scale and Cost
From: 2005

To: 2006

Cost: £36,760
Contractor / Funded Organisations
Central Science Laboratory
Keywords
Agriculture and Food Chain              
Analysis              
Analytical Chemistry              
Food Ingredients              
Food manufacturing industry              
Food Quality              
Food Safety              
Herbs              
Pesticide Residues              
Public Health              
Fields of Study
Pesticide Safety