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Final Program


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Method Challenges

EPA Method 625.1: Enhancing Benzidine Recovery

Thursday, April 9, 2026
11:15 AM - 12:05 PM PT
Location: B 4/5
Presentation Description: Benzidine recovery using EPA Method 625.1 is typically low. However, we recently observed that recoveries dropped to zero after receiving a new lot of dichloromethane from our vendor—the primary solvent used in the extraction process. This raised concerns about why the recovery was so poor and whether improvements were possible.
By examining the structure of Benzidine and considering any potential interactions we identified a likely explanation for the issue. We then conducted a series of tests, which consistently produced much higher recoveries. Over the past year, our average recovery had been about 38%, but with the adjustment we implemented, recoveries improved to about 100%.
The modification was straightforward, required no additional equipment, and can easily be applied by any laboratory. In this presentation, we will discuss the possible interactions affecting Benzidine recovery, the testing we performed, and the simple change that led to this significant improvement.

Learning Objectives:

  • Apply the changes needed to the extraction process and improve the recovery for Benzidine, a traget compound for EPA method 625.1
  • Learn about the possible interactuon between Benzidine and conditions by looking at the chemistry of whats happining.
  • apply the changes to the to the diferent extraction processes to improve the recovery of benzidine.