From wastewater to soil, sample transportation is one of the most important stages of the sample process.
While transporting samples may seem like a simple task, a variety of factors make the process challenging and complex. Ultimately, sample transportation has a direct impact on sample viability. This is why every laboratory should have clear guidelines in ensuring sample transportation processes are successful.
When it comes to thermal preservation, 2003 NELAC 184.108.40.206.1 and EPA Methods states that all samples that require thermal preservation shall be considered acceptable if the arrival temperature is either within 2 degrees Celsius of the required temperature or method-specified range OR between 0-6 degrees Celsius when the specified storage temperature is 4 degrees Celsius.
Temperature guidelines are always consistent for all sample matrices. At the laboratory, sample temperatures are monitored for adherence to NELAC and method requirements. They are collected and recorded for each sample set received at the laboratory.
Additionally, samples should be received within temperature ranges unless they’re received the same day as collected and received on ice. In the case that this rule is not met, samples may not be valid for compliance and could be rejected without adherence to thermal preservation requirements.
In our experience, here at WETLAB, one issue we’ve encountered in the winter are samples freezing, which forces us to reject samples due to their frozen state. The difficult part of sample transportation is that ice is still required, but when it’s cold outside, ice, sub-zero temps and coolers usually result in frozen samples.
So, what should you do to ensure that your sample is stored and transported correctly?
We recommend that clients transport temperature sensitive samples on ice, in a cooler and place the cooler in a temperature controlled area (i.e. – the interior of vehicles). These rules should be used whenever the outside temperatures are below 40 degrees F and above 80 degrees F.
If a sample is not preserved properly, the natural biological and chemical consistency of the matrix can change the chemistry and compromise the sample. For example, pH can change in minutes, volatile compounds may be lost, bacteria can decompose constituents, and chemical reactions may change the analytes of interest into a different species (for example NO2 can oxidize to NO3).
Transportation of samples isn’t always recognized as integral to sample integrity, but in fact it is one of the most important steps. The transfer of samples is an important time where preservation begins, and the utmost care should be taken to prevent contamination and degradation.
Some other tips you should consider when transporting samples include sealing the samples in a plastic bag or bucket with an airtight lid. You should also separate wastewater samples from drinking water by placing them in different coolers or individual zip lock bags.
Finally, make sure to provide a completed Chain of Custody (COC) document when relinquishing samples to the laboratory. The COC is a legally defensible document with information specific to the sampling plan, sample information, and transfer of custody to the laboratory. WETLAB’s digital COC can be found online at https://www.wetlaboratory.com/forms/
If you have any questions regarding sample storage and transportation, please feel free to reach out to us today, https://www.wetlaboratory.com/contact/.