Shortly after Alkemist Labs (Garden Grove, CA) added pesticide testing to their suite of services in 2022, it learned that it was common for some third-party labs to leave out testing for two pesticides (inorganic bromide and dithiocarbamates) that required extra testing steps, and advised companies to make sure they were getting the full USP (United States Pharmacopeia) panel. In reviewing 2023 data, Alkemist Labs said it discovered that 47 percent of the samples with pesticide levels above the USP <561> limits were for one of the substances often left off routine panels: inorganic bromide.

In terms of pesticides, USP <561> lists 70 reportable compounds covering 121 individual analytes, although there is nothing in the regulations that requires using the USP <561> pesticides list.

Last year, Alkemist said it alerted the industry that not all third-party labs were routinely testing for the entire list, and advised that companies make sure to specify it. After seeing so many failings for a pesticide that they know is often not tested for, the company felt it had to speak out again.

To cover the entire USP Panel requires four separate assays using two different instruments: two runs each of UPLC-MS/MS and APGC-MS/MS, which is extra time and expense. Sometimes the cost to the manufacturer is higher if those two last analytes are added to the test run.

“I can try to understand the temptation to leave those out because of the time and processing you need to run it and the expenses incurred as a result,” said Elan Sudberg, CEO of Alkemist Labs. “You need to change over the same instrument twice, each time to search for one more analyte, which can take half a day and decrease your bottom line. But given what we are seeing, it’s imperative that companies make sure their labs are doing this screening.”

Alkemist is again advising companies to carefully check their pesticide testing reports to ensure that results include Inorganic bromide and Dithiocarbamates measured and reported as carbon disulfide (CS₂).  If these compounds are omitted, then USP <561> pesticides testing is incomplete. If they see the phrase “USP <561> modified,” ask if that means newer instrumentation is being used, or if the list of substances being screened has been shortened.

For more information, visit www.alkemist.com.