Method for determining weight-average molecular weight and content of soluble salt of acidic carbohydrates

A method for determining the weight average molecular weight and the content of an acidic saccharide soluble salt in a sample, comprising the following steps:

• (1) determining the weight average molecular weight and content of acidic saccharide in a sample of acidic saccharide soluble salt by SEC-MALS;
• (2) measuring the weight percent content A of the salt-forming metal ions in the acidic saccharide soluble salt, thereby correcting the measurement result of the weight average molecular weight and content of the acidic saccharide in step (1);
• the correction is calculated according to formula 1 and Formula 2:
• Weight
• 
• 
• average
• 
• 
• molecular
• 
• 
• weight
• 
• 
• M
• w
• 
• 
• (
• Da
• )
• =
• …⋯
• 
• Mw
• 
• 
• 1
• (
• 1
• -
• A
• )
• ;
• Formula
• 
• 
• (
• 1
• )
• In the above Formula (1):
• Mw1 is the weight average molecular weight (Da) of acid saccharide directly obtained by SEC-MALS;
• A is the content of the metal ion in the acidic saccharide soluble salt;
• Content
• 
• 
• (
• %
• )
• =
• X
• Y
• 
• (
• 1
• -
• A
• )
• ×
• 100
• 
• %
• ;
• Formula
• 
• 
• (
• 2
• )
• In the above Formula (2):
• X is the mass calculated by the spectrum processing software;
• Y is the mass of the injected sample;
• and A is the content of metal ions in the acidic saccharide soluble salt.