Editorial Article: How the trailblazing Raptor Biphenyl column took the science world by storm

Paul Connolly from Restek shares the secrets to success for its most popular LC stationary phase, in this SelectScience interview

04 Jun 2020


Paul Connolly, Business Manager of Liquid Chromatography at Restek
Paul Connolly, Business Manager, Liquid Chromatography at Restek

Fifteen years after its biphenyl column first delighted scientists with the benefits of phenyl chemistry, we speak with Paul Connolly, Business Manager Liquid Chromatography at Restek, to find out the story behind this groundbreaking product and the huge impact it’s made on the science industry. Paul Connolly explores the ways in which biphenyl columns enable faster, more accurate separations for a diverse range of mass spec applications such as clinical diagnostics, drugs of abuse investigations, pharma and environmental testing, and takes a look ahead to what the future holds.

SS: If you were to give your Biphenyl column an ‘elevator pitch’ what would it be?

PC: Launched in 2005, the innovative Biphenyl (USP L11) is Restek’s most popular LC stationary phase because it is particularly adept at separating compounds that are hard to resolve or that elute early on C18 and other phenyl chemistries. As a result, rugged Biphenyl columns are extremely useful for fast separations—even with isobars—in drug, metabolite, and other analyses, especially those that require a mass spectrometer (MS). Increasing retention of early-eluting compounds can limit ionization suppression, and the Restek Biphenyl's heightened selectivity helps eliminate the need for complex mobile phases that are not well suited for MS detection.

With 15 years of unrivaled performance, Restek's time-tested Biphenyl has been proven to be the ideal column for clinical diagnostics, drugs of abuse, pharma, and environmental labs seeking universal utility for mass spec applications. Restek was the first to bring you the benefits of the Biphenyl ligand, and our LC group has the veteran technical expertise to supply and support your lab better than anyone else.

SS: Why was the column first developed and were there any specific issues it overcame?

PC: As the premier GC column manufacturer in the world, Restek chemists are the experts of phenyl and silane chemistries. We knew that there was a way to get increased aromatic compound retention in LC and we put our resources to the challenge. We first launched our unique biphenyl phase to the world in 2005 on our fully porous particle columns such as Ultra and Allure, to the delight of customers performing analysis of small molecule drug compounds, but it really took off when we combined the ultra-selective phase with our industry-leading Raptor™ superficially porous particle. Now Raptor Biphenyl is the go-to column for discerning scientists that need increased retention for dipolar, unsaturated, conjugated, or hydrophilic aromatic analytes on an extremely robust and reproducible LC column platform.

SS: How do you go about developing a column? Did customers participate in the process?

PC: At Restek new product development is always a collaboration. Internally, we pull from all over the organization to concept, design, develop, manufacture, test, and applicate. All of this is informed by customer feedback, user research, beta testing, and market needs.   

SS: Are there any particularly exciting or unusual ways this column has been applied? (please provide specific examples)

PC: We have found so many applications where Biphenyl is the superior phase for chromatographic performance. In fact, we use the Biphenyl phase more than any other. It provides excellent retention and resolution for a huge range of compounds from steroids and bisphenols to artificial sweeteners and explosives.

In LC method development, the old habit is to start with a C18, but we have learned to start with biphenyl because it offers method developers so much more. For example, you can completely change the selectivity by changing your solvent. If you are used to working with a C18, then start with acetonitrile on your biphenyl. If you are looking for differential selectivity, then just switch to methanol. 

SS: What are the top three ways this column has helped the industry?

PC: The unique selectivity of Restek’s Biphenyl phase has drastically improved the analysis of drugs of abuse testing. The ability to separate isobars and critical pairs in drug panels has made it possible to include more compounds per panel and improved the data quality and accuracy for these critical assessments. This is especially important during this terrible opioid crisis in the United States.

The biphenyl can also make a big difference because of how well it separates. When you resolve more compounds as the biphenyl can, you can avoid some unwanted re-analysis that other columns may not be able to resolve. This powerful separation capability also means biphenyl excels as a screening phase. You can spend more time analyzing positive samples instead of negative samples.  

SS: What new column types can scientists expect to see from Restek in the future?

PC: Restek has always been at the forefront of phenyl chemistries for small molecule analysis. Now we are developing new-to-world phases for difficult-to-retain polar analytes. By providing our customers with the best available solutions for their challenging polar analyte and metabolite analysis we are making their jobs better, faster and easier all the time.