Composition for determination of chloride ion

A composition for determination of chloride ion, comprising:

• (1) a maltooligosaccharide derivative possessing a non-reducing terminal and a reducing terminal, the 1-hydroxyl position of the maltooligosaccharide reducing terminal being modified by a phenyl substituted with one or more substituents selected from the group consisting of a hydrogen, halogen, nitro and hydroxy group, and said derivative having the following formula (I):
• ##STR3## wherein at least one of R.sup.1 and R.sup.2 is an alkyl having 1 to 6 carbon atoms, a substituted alkyl selected from the group consisting of hydroxymethyl, hydroxyethyl, sulfomethyl, carboxymethyl, sulfoethyl, carboxyethyl, 2-ketopropyl, 2-ketobutyl, 2-ketopentyl, 3-ketopentyl, 4-ketopentyl and benzyl, a phenyl or a substituted phenyl selected from the group consisting of 4-methylphenyl, 4-hydroxyphenyl, 4-carboxyphenyl, and 4-sulfophenyl, and the other is a hydrogen atom, or R.sup.1 and R.sup.2 may together form crosslinked methylene, R.sup.3 is phenyl or substituted phenyl which possesses a substituent selected from the group consisting of halogen, nitro and hydroxy, and n is an integer of 1 to 8, wherein the maltooligosaccharide derivative has a modified non-reducing terminal and a modified reducing terminal;
• (2) a metal chelating agent;
• (3) nonactivated .alpha.-amylase and (4) an adjuvant enzyme which is an enzyme or combination of enzymes selected from the group consisting of .alpha.-glucosidase, .beta.-glucosidase and glucoamylase, provided that the adjuvant enzyme is not present when the maltooligosaccharide derivative possesses a reducing terminal with a modifying group of said 1-hydroxyl position bound in .alpha.-orientation and said composition not containing a calcium chelate compound.