For a multi-residue method, several pesticide standards are mixed. To achieve such low concentrations, it may be necessary to create intermediate solutions and dilute further to achieve the required concentration. Working standard solutions typically have very low concentrations, in the range of 0.005 вЂ“ 0.01 Вµg/mL. It is also possible to purchase ready-made stock standard solutions of pesticide reference standards, if they are certified by the manufacturer or by an independent source.ДЎ.2 Prepare Intermediate / Working Standard Solution Liquid reference standards can be dispensed, by weight, directly into the solvent. Label the flask with all relevant information. Transfer to an appropriate volumetric flask, dissolve in a suitable solvent, and make up to the required volume to achieve the desired concentration. The required amount of pure pesticide reference standard (typically 10 вЂ“ 50 mg) should be weighed out using a 4- or 5-decimal place balance or scale, depending on the method. Individual stock standard solutions typically are prepared to a concentration of 1 mg/mL. Given the inherent errors associated with both pipetting and volumetric glassware, preparing solutions gravimetrically offers an increased level of accuracy. Accurate weighing and dispensingВ of reference standards, as well as dilution with solvents, is therefore critical. Why Accurate Preparation of Reference Standards is CrucialДЄnalysis of pesticide residues is a highly sensitive procedure requiring extremely accurate solutions. For best results, the method requires reproducible conditions and the use of high quality reference standards. Pesticide residue analysis using these techniques enables individual pesticides in a sample to be identified and quantified when compared against a matrix of known pesticides. Liquid Chromatography вЂ“ Mass Spectrometry Coupled (LC-MS), suitable for non-volatile compounds (thermally unstable molecules).Gas Chromatography вЂ“ Mass Spectrometry Coupled (GC-MS), especially for volatile compounds in complex samples.

The pesticide residues are usually analyzed by the following methods: The process for analyzing pesticide residues typically involves extracting the residues, clean-up procedures to remove other components, and an analytical procedure to identify and measure the amount of pesticide residue. MRLs vary from region to region across the world and food manufacturers exporting produce to other countries must meet all the individual MRLs in each target region. The maximum residue level (MRL) is the highest amount of an individual pesticide residue that is permitted to be present in or on food or animal feed.

In order to protect consumers, pesticide residues are under strict legislation worldwide. Through the consumption of such products, humans and animals are exposed to low levels of pesticides in their diets. Pesticides such as herbicides, insecticides, fungicides, antimicrobials and disinfectants are used routinely on agricultural products, including food and animal feed, to maximize crop output and protect produce during storage and transportation. those considered to be weeds, pests and diseases). Pesticides are chemical compounds used to kill, repel or control unwanted plants, animals and microorganisms (i.e.

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