As hard as you might try, you can never be sure that every time you step into the lab to do an experiment you are at peak performance. Sometimes you’re tired, sometimes you’re sick, and sometimes you’re just sick and tired of being in the lab. But be that as it may, the work still needs to get done and preferably with as few errors as possible. I have found the easiest way to perform consistently in the lab is to have a well-defined, three part standard operating procedure (SOP).
The first of the three part system is what most people would consider an SOP. This is where I clearly describe all of the steps (sometimes in excruciating detail) to be performed in complete sentences. Before I ever even go into the lab, I try to write this section. This process helps me answer questions like “if I want triplicate measurements for x and y, what volume of sample will I need?” After the first few times going through the experiment, I often go back and make changes to the SOP if something didn’t work as I expected or if I find I left a step out.
Once I have the first part of the SOP written, I then go through and simplify it into the two other parts: a checklist and a log sheet. For the checklist, I go through and make each step into a few word phrase. This helps make sure you don’t miss anything as you are performing your experiment without having to read through several pages of complete sentences.
The final and in some ways most important part of the SOP is the log sheet. This consists of a set of empty tables that are used to collect the same data every day. In the case of my continuous algae cultures, I have made the log sheets (and checklists) to collect one week’s worth of data. Most of these data are used in analysis and presented as results, but some aren’t; some data are used to check that nothing has changed unexpectedly from the day before. These “verification data” are equally as important as the reported data. For example, each day I record the clean water flux (CWF) estimated from the LabVIEW display; if I had a CWF of 500 LMH the previous day, but today I get 1,000 LMH for the same membrane, I would suspect there is an issue. In this way, the log sheet allows me to identify problems before they cause too much headache.
I think the three-part SOP is really helpful in the lab. Try it for yourself with your next experiment!
In case you missed the links above, here are my example documents:
This is fabulous. I am a big believer in the value of SOPs. I used to have blanks in my SOP to fill in the data as I went. But that meant reprinting the whole SOP every time and accumulating pages and pages of paper. Your three-part approach is much more streamlined and organized. Thanks!