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Pesticide Residue Analysis with HPLC

High-performance liquid chromatography (HPLC) has emerged as an essential tool for food analysis in the intensifying world of industrial agriculture. Intensive farming is subject to strict product quality and regulatory standards. This ensures that crops are free of contaminants, within acceptable limits, and are nutritionally valuable to a worldwide market.

The underlying dichotomy of health versus commerciality in intensive farming is continuously highlighted by the widespread use of agrochemicals. HPLC is widely used to detect pesticide residues in food, with a broad range of column materials and detectors assisting in the execution of extremely accurate food quality and regulatory control.

In this article, Knauer explores the health debate surrounding pesticides and how HPLC is continuing to contribute to a high-quality food supply for a growing global population.

History of Pesticide Regulation

Agrochemicals have been used to manage agricultural ecosystems for millennia. The first recorded use of a known pesticide dates to approximately 4,500 years ago when farmers in ancient Sumer dusted crops with sulfur compounds to control pests and insects. More intricate methods have been used in the modern era, with a booming global population requiring agriculture be intensified to meet an exponentially growing demand for food.

In the 1950s, the first agrochemicals were released at industrial scales. Among these was β-Hexachlorocyclohexane (B-HCH), an organochloride engineered to improve crop yields. However, studies eventually demonstrated that B-HCH was neurotoxic to both animals and humans, and the compound was subsequently banned for agrarian use.

B-HCH not only posed significant acute and chronic health risks to consumers, but it was also classified as a persistent organic pollutant (POP) by the international community at the Stockholm Convention in 2001[1]. This defines a hazardous material that is resistant to environmental degradation. Other, off-patent pesticides like dichlorodiphenyltrichloroethane (DDT) were similarly shown to persevere in soil and groundwater for years after application, polluting environments.

The European Union has established extremely strict limits on pesticide residues in food goods. These have proven very effective at reducing the concentration of legal pesticides in commercially-available products. Just 2% of products tested exceeded the legal limits for pesticide residues, and these still did not pose a risk to human health[2]. However, the debate surrounding pesticides and human health persists.

HPLC’s Role in Pesticide Residue Analysis

HPLC offers a number of robust approaches suitable for pesticide residue and food analysis. Reversed-phase liquid chromatography with ultraviolet detection is one of the most common HPLC techniques used for analyzing pesticides, due to the universality of the detection mode. This is essential for ensuring that accepted pesticide levels remain below accepted limits of safety for human consumption. The World Health Organisation (WHO) alludes to the importance of pesticide residue testing:

“None of the pesticides that are authorized for use on food in international trade today are genotoxic (damaging to DNA, which can cause mutations or cancer). Adverse effects from these pesticides occur only above a certain safe level of exposure”[3].

HPLC is one of the most important techniques for maintaining those aforementioned safe levels.

Prior to HPLC testing, however, it is often prudent to conduct sample preparation and cleaning. This is typically determined by the nature of the sample. HPLC columns are generally suited to aqueous samples but are not as versatile with higher molecular weight matrices. Olive oil, for example, has a high molecular weight matrix which makes analysis via HPLC very difficult. Size exclusion chromatography (SEC) is commonly used to extract pesticides and purify compounds, both polar and non-polar, before characterizing them via HPLC.

HPLC Food Analysis with Knauer

Alongside a suite of HPLC instruments and tools, Knauer offers the AZURA® GPC Cleanup System for automated sample cleaning of multi-pesticide residues in complex samples. It can help reduce matrix effects and improve recovery for compounds of interest by up to 70%. This extremely efficient system demonstrates our increasing capability to assist in the regulatory testing and quality control procedures of food goods in an increasingly challenging market.

Sources:

[1] https://www.who.int/news-room/fact-sheets/detail/pesticide-residues-in-food


[2] https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/j.efsa.2017.4791

[3] https://www.who.int/news-room/fact-sheets/detail/pesticide-residues-in-food



If you would like to learn more about performing pesticide residue analysis with Knauer HPLC products, please do not hesitate to contact us directly.

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