22477
A singlet oxygen quencher , sodium azide , could not completely inhibit the damage of human serum albumin , suggesting that the electron transfer mechanism contributes to protein damage as does singlet oxygen generation .
 oxygen, sodium azide, oxygen
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 oxygen, sodium azide, oxygen