Intracellular iron content TPTZ method

[TB_84]

Hi all. I'm trying to determine the intracellular iron concentration of bacterial cells through the TPTZ method. I was wondering if you have any suggestions regarding:

 

1. When I add the reaction mixture (classical FRAP reagent + ascorbic acid 1%) to a serial dillution of cell lysates, the more concentrated developed turbidity and no color and the less concentrated no color. The reaction with the iron standards worked just fine, so i think it's not the reagent. Any ideas on how to overcome the turbidity issue?

 

2. A reliable method to extract all the iron content from cell lysates, including heme proteins and other iron-binding proteins.