Improvements in Cryptosporidium Recovery and Variability ThroughModifications to USEPA Method 1623

摘要

The current project explored various modifications to United StatesEnvironmental Protection Agency Method 1623. Method 1623 is a performance-basedmethod for the analysis of Cryptosporidium and Giardia in water. The variousmodifications that were tested included: filter type, slide type, methanol fixation, elutionbuffer, IFA kit, and sample resuspension method. These variations were assessed interms of the mean percent recovery and percent relative standard deviation that wasachieved. The first modification assessed was stain, followed by methanol fixation, andslide type. After that initial assessment, the best combination was selected and used inthe processing of other samples. After a filter was selected, subsequent samples weresubjected to changes in transfer method, and elution buffer. All future modifications,that increased the percent recovery, without any adverse effects, were used for theanalysis of subsequent samples. The desired end result was an optimized method thatachieved the best percent recoveries and the least variable recoveries in various watermatrices.