Now, before you even get to collecting itself, you will need to prepare adequately for it. Here are some of the things that you should consider.
Personal Protection Equipment (PPE) – Since there is a very high chance of personal contamination, you will need to protect yourself by wearing appropriate personal protective equipment, including masks, gloves, and appropriate footwear.
Prevent Contamination – Due to the low limits of detection necessary to accurately assess pesticide residues, testing material and products should be handled with a lot of care. So, ensure that you use clean tools and that your protective gear isn’t contaminated in any way when collecting each sample.
Sample Storage and Transport – Pesticides also degrade during transport. So, for you to maximize the correlation between pesticide residues at the sample site and the ones reaching the laboratory, the samples need to be transported as soon as possible. Keep the samples as cool as possible and away from direct sunlight. The samples should also be clearly labeled to avoid any potential mix-ups. For example, soil samples taken from multiple locations within a given area should have a distinct identifier for tracking purposes.
Collecting Your Samples
First and foremost, you need to determine if the sample you have chosen to test represents your end goals.
Soil Sampling – Generally, pesticide residues are most present in the soil’s top layers. Layers beneath can also be analyzed if suspicion of residues are present also. Take a representative amount of sample using a clean soil auger, down to a depth of 15cm. Then, mix samples thoroughly to come up with a composite sample, and then put 500g of this particular sample in a bag and clearly label it.
Vegetative Tissue Sampling – If you are looking to test a vegetative sample, it may be best to collect the areas most prone to pesticides. For fruits and vegetables, it is important to sample the areas meant for human or animal consumption. Please note, during transport, vegetative tissue can “sweat,” which could lead to the rapid development of molds, which in turn lead to microbial degradation of the pesticide residues. Therefore, samples should be kept as cool as possible during transport.
Laboratory Analysis – Once collected, samples can be shipped or delivered to Adamson Analytical Laboratories. With our onsite modern residue analysis equipment (LC-MS/MS, GC-MS/MS, GC, HPLC) we can test different pesticides classes:
Chlorate & Perchlorate
Chlormequat & Mepiquatchloride
Ethyl Bromide Calculated as Bromide
Fosetyl-Al + Phosphonic Acid
Paraquat & Diquat
Determination of about 700 Pesticides (Multi-Residue Method)Source: https://www.adamsonlab.com/how-to-collect-samples-for-pesticide-residue-testing/