Guanidine Thiocyanate (CAS # 593-84-0). You state that the subject product, Guanidine Thiocyanate (CAS # 593-84-0), which is also called Guanidinium Isothiocyanate is a pure chemical compound. It is used as a general protein denaturant, although it is most commonly used as a nucleic acid protector in the extraction of DNA and RNA from cells. The Guanidine Thiocyanate that you wish to import into the United States is indicated to be “99+% pure”, and is used as a reagent in the preparation of test kits.
Please importantly note that only the relevant portion of the related US CUSTOMS RULING is displayed above. You may refer to the said customs ruling for the entire ruling explanation.