CHES (buffer)
CHES (N-cyclohexyl-2-aminoethanesulfonic acid) is a buffering agent. CHES buffers have a useful range of pH 8.6–10. It typically appears as a white crystalline powder. Effect of impurities
Commercial prep of CHES (and other sulfonylethyl buffers like MES, BES, and PIPES) can contain a contaminant oligo(vinylsulfonic acid) (OVS), which is a polyanionic mimic of RNA, and can be a potent (pM) inhibitor of RNA binding proteins and enzymes. References

External links

Buffer solutions
Sulfonic acids