Maltooligosaccharide derivatives represented by the general formula:
wherein at least one of R¹ and R² denotes a radical represented by: R³-S(O) m -R⁴ or R³-CO-R⁴, and the rest of them denotes hydrogen atom, an alkyl radical containing 1 to 6 carbon atoms or a phenyl radical, in which R³ is an alkyl radical containing 1 to 5 carbon atoms, R⁴ is an alkylene radical containing 1 to 5 carbon atoms, and m is 1 or 2, R⁵ denotes a substituted or non-substituted phenyl radical, and n denotes an integer of 1 to 8 ; and reagents comprising the maltooligosaccharide derivatives.