The Invitrogen Qubit Endotoxin Detection Assay Kit is a sensitive and easy-to-use fluorescent endpoint assay for use on the Qubit Flex Fluorometer that uses amebocyte lysates to quantify endotoxin in protein, peptide, antibody, or nucleic acid samples. Amebocyte lysates are widely used as a simple and sensitive assay for the detection of endotoxin lipopolysaccharide (LPS), the membrane component of gram-negative bacteria.

Features of the Qubit Endotoxin Detection Assay Kit include:
• Highly sensitive with a broad range—detect as little as 0.01 EU/mL to 10.0 EU/mL
• Flexible—suitable for wide range of samples, including DNA, RNA, plasmids, antibodies, and more
• Easy to use—when paired with the Qubit Flex Fluorometer, calculations are performed automatically, helping reduce the potential for error

Endotoxin levels in the samples are accurately determined using the included endotoxin standard of known concentration that is derived from E. coli strain O111: B4. Determining endotoxin levels is important to assess the efficiency of endotoxin removal methods and prevent endotoxic shock, inflammation, and/or sepsis in tissue culture cells and animals injected with endotoxin-contaminated proteins.

When endotoxin encounters the amebocyte lysate, a series of enzymatic reactions results in the activation of Factor C, Factor B, and pro-clotting enzyme. The activated enzyme catalyzes a cleavage event in the substrate to produce a strong fluorescent signal. After stopping the reaction, the resulting signal is measured on the Qubit Flex Fluorometer. The correlation between fluorescent signal is proportional to the endotoxin concentration in the sample.

Notes
• Designed for use with the Qubit Flex Fluorometer (Cat. No. Q33327) and not currently for use on Qubit 4 Fluorometers
• Optimized for use with Qubit Flex Pyrogen Free Assay Tube Strips (Cat. No. Q32893)
• Use the Qubit Flex System Verification Assay Kit (Cat. No. Q33254) prior to first assay run