I am currently researching the impact of different antimicrobials on the amount of endotoxin released from two different gram-negative bacteria types. I am using nutrient broth as the growth medium and it will end up being transferred into my samples for endotoxin analysis. I am using the ToxinSensor ™ Chromogenic LAL Endotoxin Assay Kit and a spectrophotometer for my analysis. The instructions state not to use a colored sample as it will interfere with the color change when detecting the presence of endotoxins. Is there a way to account for the color of the nutrient broth as the "standard" like I would for the water-blank step or do I need to remove the color completely? How could I remove the color without using something that will damage my sample?

If needed for reference, the instructions for the kit are listed at this link: https://www.genscript.com/product/documents?cat_no=L00350&catalogtype=Document-PROTOCOL

Thanks!