Purpose

The Agrochemicals Analysis Sub-Group was established in 1972 with the main objective to improve methods for the analysis of the most used Crop Protection Agents (CPAs) in tobacco production. Identification and quantification of CPA residues are key processes in determining the integrity of tobacco leaf. The presence of certain proscribed CPAs and non-compliance with companies’ internal standards can lead to rejection of new material at sale. Specific CORESTA Recommended Methods were developed by the Sub-Group mainly for organochlorine insecticides, dithiocarbamate fungicides and the most common sucker control products.

At the time tobacco and tobacco products were primarily analysed by the main cigarette manufacturers in their internal Quality Assurance (QA) laboratories and by very few commercial laboratories, then mostly located in important tobacco production areas such as North Carolina and Zimbabwe.

Since then dramatic improvements to analytical instruments and associated software have allowed the creation of Multi-Residue Methods (MRMs) able to analyse a very large number of CPAs in a single tobacco sample with very low Limits of Detection (LoDs) / Limits of Quantitation (LoQs) and with Recovery Rates within the required tolerance.

At the same time the tobacco industry introduced comprehensive testing programmes for raw material and finished products and has moved from internal to commercial laboratories to improve the sample throughput. This has led to reduced Turn Around Time (TAT) enabling analysis results in a very short time, which has optimised their internal control procedures. Increased awareness on CPA integrity and the regulatory requirements have intensively boosted the necessity for analyses and the reliability and consistency of the results.

In light of these developments, the Agrochemicals Analysis Sub-Group updated its objectives in 2004, with the result that its main objective now is to conduct regular proficiency tests for Multi-Residue Methods performed by commercial and tobacco industry laboratories. The need for a proficiency testing is because the tobacco matrix is one of the most difficult to be analysed and requires laboratories to adopt specific steps in the methods for sample extraction, extract clean-up, instrument calibration with matrix-matched standards, etc. Due to the complexity of the tobacco matrix characteristics, CPA residue analysis on tobacco requires laboratories to validate their Multi-Residue Methods specifically for tobacco. For ISO/IEC 17025:2017 accreditation, laboratories are required to participate in regular proficiency tests in order to assess their overall performance in comparison with other laboratories.

The CORESTA Agrochemicals Analysis Sub-Group proficiency test is conducted every year in collaboration with the Food Analysis Performance Assessment Scheme (FAPAS) from the Food and Environment Research Agency, UK (FERA). This collaboration has facilitated the realisation of the first and only official Proficiency Test conducted on the tobacco matrix. Since 2005, around 25 laboratories have taken part in the annual CORESTA-FAPAS Proficiency Test which has contributed to the consistent performance improvements by the participating laboratories.

The laboratory performance assessment has allowed the tobacco industry to identify the best internal and commercial laboratories worldwide to assure reliable and timely results, able to cover an extremely large testing scope, including all CPAs listed in the CORESTA Guide No. 1 Guidance Residue Levels (GRLs) and other CPAs which are part of a company’s internal standards and regulatory compliance requirements.

The organisation of the CORESTA-FAPAS Proficiency Tests also permits the identification of issues with the Multi-Residue Method analysis of specific CPAs and for which dedicated Joint Experiment Test Studies (JETS) are conducted among laboratories. A Technical Guide (CORESTA Guide No. 5) and Technical Notes are produced by the Agrochemicals Analysis Sub-Group to provide laboratories with the know-how for CPA residue analysis on tobacco, with specific information on the analysis of certain CPAs.

The Agrochemicals Analysis Sub-Group activities have created a “tobacco laboratory network” within which laboratories, chemists, agronomists can find a dedicated forum to discuss CPA residue analysis on tobacco and organise specific training sessions during Agrochemicals Analysis Sub-Group meetings or at hosting laboratories’ premises.

CORESTA, through its Agrochemicals Analysis Sub-Group, provides a service to the tobacco industry with the evaluation of laboratory performance and consequently offers the tobacco industry the possibility to work with the best and most reliable laboratories worldwide and to have confidence in their results.

Meetings over the last 18 years

• Winston-Salem, NC, USA - July 2006
• Brufa di Torgiano, Italy - June 2007
• Lundsbrunn, Sweden - June 2008
• San Salvador de Jujuy, Argentina - September 2009
• Trier, Germany - July 2010
• Bergerac, France - July 2011
• Vienna, Austria - June 2012
• Raleigh, NC, USA - June 2013
• Hamburg, Germany - June 2014
• Victoria Falls, Zimbabwe - June 2015
• Chiang Mai, Thailand - July 2016
• San Salvador de Jujuy, Argentina - September 2017
• Gothenburg, Sweden - June 2018
• Dubai, United Arab Emirates - July 2019
• Online - September 2020
• Online - September 2021
• Dubai, United Arab Emirates - October 2022
• Charleston, SC, USA - October 2023
• Thessaloniki, Greece - end of July 2024 (exact date TBA)

The Agrochemicals Analysis Sub-Group meeting is usually a two-day event with presentations on Sub-Group activities and specific technical presentations on various topics related to CPA residue analysis on tobacco and in general. The meetings either take place near to where the host laboratory is located or in a tobacco production country to allow participants to familiarise themselves with the various production aspects of the tobacco crop.  Meetings were exceptionnally held online during the Covid pandemic.

Achievements

• Established a well organised proficiency test with the regular participation of a number of core laboratories together with new ones.
• Improved overall laboratory performance.
• Provided the tobacco industry with a laboratory performance assessment scheme and access to high quality laboratories to meet the demand for testing capability and reliable analytical results.
• Created a tobacco laboratory network.
• Produced the CORESTA Guide No. 5 (updated Oct. 2018) and Technical Notes on Maleic hydrazide (revised Oct. 2018), Dinitroanilines, Methamidophos, Pyrethroids, Acid herbicides (revised Nov. 2019) and Dithiocarbamates.

[In June 2016, the CORESTA Scientific Commission moved the Agrochemicals Analysis Sub-Group from Product Technology Study Group to the Agronomy and Leaf Integrity Study Group]

Updated November 2023