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TSS - SPIONs were developed by chelation between thiolated chitosan - thioglycolic acid ( chitosan - TGA ) hydrogel and iron ions ( Fe ( 2 + ) / Fe ( 3 + ) ) .
 Chemical: thioglycolic acid; Chemical: TGA; Chemical: iron; Chemical: Fe ( 2 + ); Chemical: Fe ( 3 + )
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: thioglycolic acid; Chemical: TGA; Chemical: iron; Chemical: Fe ( 2 + ); Chemical: Fe ( 3 + )