Method for preparing analysis sample, analysis method, and kit for preparing analysis sample

A method for preparing an analysis sample from a sample containing a glycan, the method comprising:

• 1) Performing esterification reaction on the sample that subjects at least a part of a sialic acid included in the glycan to esterification other than lactonization;
• and
• 2) Performing amidation reaction that converts an esterified form of the sialic acid modified through the esterification other than lactonization according to step 1 into an amidated form through contacting the at least a part of the sample after the esterification reaction according to step 1 with an amidation reaction solution containing at least one compound selected from the group consisting of ammonia, amines, hydrazine, hydrazine derivatives, and hydroxyamine, and salts thereof to be reacted with the sialic acid modified through the esterification.