One of the original Good’s buffers it contains 125mM MES and 750mM NaCl at pH 6.5. MES solution has a pKa value near physiological pH, it is not absorbed through cell membranes, and it is essentially transparent to UV light.
Technical Information :
pKa (25°C) : 6.10
Warning: For laboratory use only. Not fit for agricultural, household, clinical use or human consumption.