Using VUV Analyze for Quality Assurance / Quality Control
Quality assurance/quality control (QA/QC) is nobody’s favorite thing to do, but it’s necessary to make sure a lab process is working as intended. Testing your instrument’s performance is an important aspect of QA/QC, and we can do that using VUV Analyze Software. Under ASTM D8071, there are three standards we use on a regular basis: VUV-RT, VUV-1, and VUV-CS. VUV-RT is a retention time standard used to create the retention index (RI) file, VUV-1 is a standard mixture of 28 compounds found in gasoline, and VUV-CS is a standard gasoline sample. The RI file can be created by loading the VUV-RT run file into the Create RI File box, and VUV-1/VUV-CS can each be checked using the Calculate Response and Analyze QC boxes, respectively, as shown in Figure 1.
VUV-1 is used to check three aspects of instrument performance:
- Benzene response – the response of benzene in a sample can be used to set the instrument at the proper makeup gas pressure. A proper makeup gas pressure is important to make sure eluting compounds have the proper residence time in the detector flow cell.
- Baseline stability – VUV Analyze checks the baseline at the beginning and the end of the run and will fail the test if the baseline drifts beyond a certain amount. Fluctuating baselines are often caused by leaks somewhere along the GC-VUV flow path.
- PIONA values – the PIONA values measured are compared to the standard values built into VUV Analyze.
Sample VUV-1 results can be seen in Figure 2.
Like VUV-1, VUV-CS is used to check the PIONA values being measured. Example results can be seen below in Figure 3.
However, what if you aren’t running gasoline samples, or what if your company has their own QA/QC samples they’d like to run? No problem. The limit values used in the QA/QC buttons can be altered to tailor your QA/QC samples.
Note: These settings are meant to be adjusted ONLY by experienced VUV Analyze users. Before continuing, please consider the following points:
- This is not a full tutorial; before adjusting these settings, you should contact VUV Analytics first to get the proper assistance.
- Currently, these settings are adjusted by altering the .ini files. Keep a copy of the original .ini files before making any changes.
For this example, I am using a gasoline sample spiked with 2,5-dimethylfuran, an environmentally friendly additive used as an octane booster. Suppose I want to check the gasoline sample’s content of paraffins, aromatics, benzene, and 2,5-dimethylfuran, which isn’t covered by the default Analyze QC check. Figure 4 is a snapshot of the .ini file I set up, and Figure 5 shows the results of a sample I prepared.
If these custom QA/QC checks are of interest to you, please reach out to us and let us know how we can help! Since this part of VUV Analyze is still in development, we’d love to get some feedback from our customers. If you have feedback please email it to info@vuvanalytics or leave your comment below.
Otherwise, stick around for the final part, Part 4 and we’ll take a look the Analytes to Include feature.