The product is the core raw material for nucleic acid extraction after strict screening and quality control. Guanidine thiocyanate is commonly used as lysate and denaturant, and agarose gel sol in the process of nucleic acid extraction. Large 2m guanidine isothiocyanate can mediate the adsorption of isodna on glass fiber filter membrane or silica magnetic beads. Different from guanidine hydrochloride, guanidine isothiocyanate has a high absorbance value in A230, 0.5% (w / V) guanidine isothiocyanate (~4mm), and its A260 / A230 is less than 0.5. For the nucleic acid obtained by using this lysate, its A260 / 230 will be poor in low concentration nucleic acid samples, but it will not affect PCR, RT-PCR and second-generation sequencing.