6902
Gel permeation chromatography analysis was used to determine the molecular weight distribution and changes of polymer structure .
 material: Gel; process parameter: weight; concept or principle: distribution; material: polymer
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
 Entities: Gel, weight, distribution, polymer 
Answer:
 material: Gel; process parameter: weight; concept or principle: distribution; material: polymer