Ponceau S, Acid Red 112, or C.I. 27195 is a sodium salt of a diazo dye of a light red color, that may be used to prepare a stain for rapid reversible detection of protein bands on nitrocellulose or polyvinylidene fluoride (PVDF) membranes (Western blotting), as well as on cellulose acetate membranes. A Ponceau S stain is useful because it does not appear to have a deleterious effect on the sequencing of blotted polypeptides and is therefore one method of choice for locating polypeptides on Western blots for blot-sequencing. It is also easily reversed with water washes, facilitating subsequent immunological detection. The stain can be completely removed from the protein bands by continued washing. Common stain formulations include 0.1% (w/v) Ponceau S in 5% acetic acid or 2% (w/v) Ponceau S in 30% trichloroacetic acid and 30% sulfosalicylic acid.

CAS：6226-79-5
中文别名：3-羟基-4-[2-磺酸基-4-(4-磺酸苯基偶氮)苯基偶氮]-2,7-萘二磺酸四钠盐;丽春红S;酸性红112;3-羟基-4-[2-磺酸基-4-(4-磺酸苯基偶氮)苯基偶氮]-2,7-萘二磺酸;
英文别名：ACID RED 112;ATX PONCEAU S RED;Ponceau S Extra;c.i.acidred112;FAST PONCEAU 2B;Ponceau Red S;
分子式：C22H12N4Na4O13S4
分子量：760.569
精确质量：759.887
Psa：331.99
Logp：7.3158

UNII：T1C2UGS05F

外观与性状：棕色粉末
密度：1.01g/mLat 20°C
折射率：n20/D 1.338
水溶解性：10 g/L
稳定性：Stable. Incompatible with strong oxidizing agents.
储存条件：Store at RT.

RTECS号：QJ6600000
安全说明：S26-S36-S37/39
危险类别码：R36/37/38
WGK Germany：3
海关编码：32041200
危险品标志：Xi