In the last three articles, I discussed the laboratory’s responses or defenses used to reply to your questions about laboratory results that place stress on the success of your business. The Quality Control (QC) results can cause this stress if they are not run correctly to answer the following questions:
- Are the laboratory results really true?
- Can the laboratory accurately analyze sample products like my sample?
- Can the laboratory reproduce the sample results for my type of sample?
Now let’s discuss the most important QC test that will protect your crop and business. That QC sample is the Matrix Sample. In the last article in this series, you were introduced to many QC samples. The Matrix Sample and Duplicate were some of them. Take a look back at Part 3 to familiarize yourself with the definitions.
The key factors of these QC sample types are:
- Your sample is used to determine if the analysis used by the laboratory can extract the analyte that is being reported back to you. This is performed by the following steps:
- Your sample is analyzed by the laboratory as received.
- Then a sub-sample of your sample is spiked with a known concentration of the analyte you are looking for (e.g. pesticides, bacteria, organic chemicals, etc.).
- The difference between the sample with and without a spike indicates whether the laboratory can even find the analyte of concern and whether the percent recovery is acceptable.