Aptagen, LLCDNA Arsenic(III) Small Organic 4.95 nM (reported value) Selection buffer: 150 mM NaCl, 50mM HEPES, 0.5 mM MgCl2, 0.5 mM CaCl2 NA If the oligo is a known aptamer sequence: For binding studies, perform a refolding program to ensure proper function (i.e. binding to antigen or target). Refer to the aptamer reference source for the appropriate refolding parameters and binding conditions. Note: it is unknown whether aptamer functions properly without refolding. Wu et al. converted this aptamer into a biosensor that could colorimetrically detect As(III) at concentrations as low as 10 ppb when using Hexadecyltrimethylammonium bromide (CTAB) as the cationic surfactant, or as low 5 ppb when using hexadecylpyridinium chloride monohydrate (HPCM) as the cationic surfactant.