... quality and technical index: Content(as DMSO), % : ≥ 99.8 Crystallization point, : ≥ 18.10 Acid value (0.1N/ ... and technical index:Item Index StandardContent(as DMSO), %: ≥ 99.9 Crystallization point, : ≥ 18.3 Refractive index: ... and technical index:Item Index StandardContent(as DMSO), %: ≥ 99.9 Crystallization point, : ≥ 18.35 Acid value(mgKOH/ ... residue, PPM: ≤ 5. Heavy metals, %: ≤ 10 DMSO 99.8%