Abstract: A sugar ester derivative of the general formula (I) ##STR1## wherein G stands for a group of the formula (A) ##STR2## or a group of the formula (B) ##STR3## wherein .lambda. means 0 or 1; at least one of R.sub.1 and R.sub.2 means an ester residue of a saturated or unsaturated fatty acid having 1-30 carbon atoms and the other group means hydrogen atom or acetyl group, and R.sub.3 means a group of the formula (C) ##STR4## wherein X means a halogen atom, m means an integer of 0 to 4, Y means hydroxy group, an alkoxy group, a carboxyl group or sulfonic acid group, n means 0 or 1 and Z means nitro group or nitrovinyl group and its use.

Abstract: A composition for determination of chloride ion, comprising a maltooligosaccharide derivative possessing modified or non-modified non-reducing terminal and modified reducing terminal, a metal chelating agent, .alpha.-amylase and an adjuvant enzyme, provided that the adjuvant enzyme may not be contained when the maltooligosaccharide derivative possesses reducing terminal with a modifying group bound in .alpha.-type, which does not require maintenance and control of special instruments and special treatment of waste liquors, affords good analytic efficiency, determination precision and linearity, and is capable of suppressing rise of reagent blank and giving accurate determination values from test samples showing high values.

Abstract: An element for assaying a rheumatoid factor quantitatively in biosamples, comprising a polyalkyl methacrylate solid carrier and serum albumin immobilized thereon, the serum albumin being immunologically bound with anti-albumin rabbit IgG, and a method of assaying a rheumatoid factor quantitatively by immunoglobulin class in which the element is reacted with the biosample, then the element-bound rheumatoid factor is reacted with enzyme-labeled anti-human IgG, enzyme-labeled anti-human IgM or enzyme-labeled anti-human IgA, and then the amount of the marker enzyme is determined.