Perchlorate and iodide in biological samples

In recent years perchlorate has been detected in a number of samples, including water sources, fruits and vegetables, and milk. Perchlorate is known to inhibit the uptake if iodide by the thyroid gland thus inhibiting the production of essential thyroid hormones. Initially it was unclear whether the perchlorate being found was natural or anthropogenic, and the extent of perchlorate existence outside the US was largely unknown. We developed a simple milk extraction method to process milk samples for analysis by IC-MS, which showed good recoveries for perchlorate and iodide and was comparable to the milk processing method developed and used by the FDA. Several bovine milk samples from Japan were processed and analyzed for perchlorate content. Samples from Japan were found to have ~1.6 times more perchlorate than those found in the US. This finding indicates that perchlorate dispersal is natural, in most cases, and not unique to the US alone. It is most likely that perchlorate has little to no effect on ones health as long as they have adequate iodine nutrition. We explored the use of different internal standards for measuring iodine in milk and urine samples by MS. It was found that certain internal standards worked for certain samples but using 129I universally performed as the best internal standard for iodine analysis.