The annual Gulf Coast Conference (GCC) was held in Galveston, TX a couple of weeks ago. This year’s conference was particularly exciting because it was my first conference experience with ARC! I was able to present the application of the Polyarc in detailed hydrocarbon analysis (DHA), talk face-to-face with some of our customers in the oil and gas industry, and hear firsthand all of the excitement around our new low temperature O-FID, which will be available in early 2020.

The Polyarc for DHA:

Detailed hydrocarbon analysis encompasses the classification of oxygenated spark ignition fuel blends. ASTM methods D6729 and D6730 give the ability to determine the weight percent of parrafins, olefins, naphthenes, and aromatics (PONA) groups, as well as oxygenates.

A Canadian joint government and private analytical laboratory was kind enough to provide us with gasoline samples and their own data for the CAN/CGSB-3.0 method, which is a similar method to ASTM D6729. We ran a quick and automated version of DHA following the same temperature ramp scheme and phase column, but without a tuning column or cryo-focusing, to compare the results between the standard method to those using the Polyarc. Due to the Polyarc’s universal FID response (because of the conversion of all organic compounds to methane), we were able to run the gasoline samples without calibration or standards.

DHA is not necessarily the best choice to provide classification at a high level due to the process of identifying the PONA groups and assumptions made during these steps. Identification is based on a standard relative retention time provided in the analytical software and a quality control sample and compound quantification is based on the relative response factor and ratio of peak areas. The sample data provided to us had an unknown compound weight percentage of more than two percent. Regarding our results, we were able to very closely match values obtained with the Polyarc to the official CGSB-3.0 method without using calibration standards or the chromatography tuning methods that were previously mentioned (Table 1).ARC vs. D6729 CAN/CGSB-3.0

Table 1. Weight percent comparison of basic compound groups in gasoline; CGSB-3.0 and ARC results.

Our identification of each peak was done using an MS in a configuration where the column effluent is split to both MS and Polyarc/FID. This gives us the ability to quantify and identify in one single injection. Another benefit of this configuration is the alignment of the chromatograms, which allows for easy peak matching (Figure 1)

Figure 1. FID (top) and MS (below) chromatograms with ethanol peak highlighted

Download DHA Presentation Slides

PolyarcBeyond DHA – Research Fuels:

We also see the Polyarc being used in the analysis of research fuels. According to users, they previously would manually apply like-compound response factors to each peak in order to obtain a total mass balance. In some cases, to save time on a multiple hour-long process, they would group ranges of peaks within a similar functional group, integrate them as one, and apply a relative response factor from a similar calibrated compound (e.g., all C8 aromatics calibrated against xylene). With the Polyarc, there is no longer a need to worry about response factor matching on the FID. This same analytical lab is now able to achieve greater than 90% mass balance closure on 600+ peaks in their research biofuel, whereas before an 80% closure was acceptable.

Beyond the Polyarc at ARC:

ARC is releasing a new low temperature O-FID with an anticipated release date of early 2020. Being at the booth, I had never seen so much excitement about a single product in person. It made me think of the first time hearing a customer exclaiming that our Jetanizer is the ‘most elegant’ device. The Jetanizer is the most robust, poison-resistant methanizer, that fits into the FID jet itself – no longer requiring the use of toxic nickel catalysts and additional plumbing or heaters. The new O-FID is will operate at a lower temperature than existing reactors, while also providing improved robustness and compliance with ASTM D5599. Yes – you are right to be excited!

At ARC, we love to apply our expertise in catalysis and microreactor design to make chemical analysis easy. Do you need a specialty reactor? Learn more about our services here!