Posts Tagged ‘LC’

Modifying QuEChERS for complicated matrices- Dry Samples

Before getting in to this discussion, I recommend reading my previous blog post first regarding classical applications for methods based on Quechers. https://blog.restek.com/quechers-dspe-selection-which-one-is-best/ QuEChERS methods were originally written to analyze pesticides in fruit and vegetable matrices, most of which have high water content and low fat content. More recently, the technique has been used for […]

Shutting down your LC during a quarantine period?

It certainly does not only pertain to a quarantine period, but certainly more likely during the current Covid-19 crisis. Some of you might be needing to shut down your projects for a while. If you will not be using your LC column for more than 3 days, here are some recommendations and tips that might […]

Why is my LC Retention Time Shifting?

If you have experienced retention time shifts with LC, you know it can be complicated and can cause problems with quantitation if not resolved. Hopefully this post will help you navigate through troubleshooting this situation. For the purposes of this discussion, we will be discussing changes in retention on one individual column, not differences from […]

EXP Fittings: Which Nut Do I Need?

Our brilliant friends at Optimize Technologies are continually innovating and making our lab lives easier. We love their patented EXP Titanium Hybrid Ferrule technology that is truly universal. You can use it on any tubing, any 10-32-port, any instrument—wrench-tight to 20,000 psi. This fully UHPLC-capable EXP ferrule is used with all EXP nuts. Restek offers […]

Can I use a 100% aqueous mobile phase with my LC column?

You might be asking this because you have read that not all columns are OK to use with highly aqueous content (>95%) in the mobile phase.  Or maybe the caption caught your eye because you have recently encountered some difficulty with using highly aqueous mobile phase. There is a phenomenon called “phase dewetting” that can […]

Which LC column should I use for my method?

We understand that with so many products on the market, choosing a column to get started can be difficult. Of course, column selection depends on what type of method you are following and what kind of LC system you have in your lab. Let’s begin by looking at our choices for the more traditional, fully […]

Should I use LC or GC for my analysis?

Although most analysts already know which approach they need to use for analysis, this is occasionally a topic of discussion.  While this blog post is not meant to give an absolute answer for each specific application, I hope to provide some tips to steer you in the general direction towards a solution, if this is […]

How can I use Raptor columns and the EXP Direct connect holder with stainless steel fittings?

Some customers may find themselves with this scenario. You have an HPLC instrument with existing stainless steel tubing and fittings and you are getting ready to install a Raptor column. The end of your tubing may very well look like the one shown above. Here are some questions you might have.   Can I attach […]

LC Columns: High-Pressure Survival of the Fittest!

As an R&D Chemist charged with developing the perfect packing method for new LC columns, one of the challenges is finding a packing method that results in a column which not only passes QC specifications but also passes our arduous lifetime analysis. During lifetime testing our columns are subjected to 1,000 continuous injections at 12,000 […]

The Clog Blog

Clogging and over pressuring are definitely problematic for Liquid Chromatography columns. Back in 2005 John Dolan’s sage advice to chromatographers to make an LC column last forever was simple, “Never open the box!” As John pointed out, this is not practical and I have to agree. But as an LC column manufacturer I have seen […]