I did some column tests in my lab where I needed to detect the DOC fractions using LC-OCD. For the abiotic columns I used sodium azide to restrict the biofilm formation. I did LC-OCD to detect the DOC fractions. For some reasons the DOC fractions could not be detected through LC-OCD for the abiotic column samples. Although the total DOC was detected in the same samples through the TOC analyzer. The samples contained DI water, trace methanol, MC-LR and Sodium azide. Is there any literature on it explaining similar situation??