Archive for the ‘LC’ Category

Chiral separation on a C18 column? Separation of d- and l- Amphetamines, Part I

Did you know that chiral chemistry was discovered by Louis Pasteur, a French chemist and biologist in 1848? However, it took about a century to find that chirality plays a key role not only in the life of plants and animals, but also in several aspects of drug design, and both pharmaceutical and illicit drug […]

Afraid of HILIC? Watch These Videos and Overcome Your Fear!

Hydrophilic Interaction Liquid Chromatography or HILIC is a powerful tool to analyze polar compounds that have limited retention on typical reversed-phase columns. The power of HILIC can be utilized across multiple markets including environmental, food safety, and clinical diagnostics. But to be honest, it can be challenging to implement a HILIC method and more considerations […]

My fitting nut has broken off in the end of my LC column. What to do?

If excessive force is applied at an angle to a fitting or column connector, the ferrule could become stuck in the column end fitting. Likewise, a PEEK connector, column nut or plug can also break and leave part of it in the end fitting. Stainless steel nuts are much harder to break, although a stainless […]

Pesticides are like Siblings – some get along well and some don’t – No. . .Really?

My colleague, Joe Konschnik and I have been asked by many food chemists out there about how much they can trust their pesticides mixes after they combine them into one single larger mixture for calibrating their instrument, or monitoring the accuracy and precision of their method – and rightfully so.  Well, like siblings, sometimes they […]

What’s That Smell? Odor Analysis with Raptor Biphenyl

  A wide variety of chemicals are used in the production of consumer goods, and most of them have odors that are released into the atmosphere and/or linger on the final product.   Everyone gets really excited about “new car smell,” but sometimes residual odors on fabric or plastic are off-putting. I noticed that the knock-off […]

What’s in a name? A C18 by any other name would not be the ARC-18

You have probably read or been told numerous times and in numerous ways that not all C18 columns are the same. And that is very true. Particle morphology, bonding chemistry, and add-ons like end capping all influence the retention and selectivity of this workhorse LC phase. At Restek we have an interesting C18 phase that […]

Dilute, Shoot, and Elute – am I missing anything? YES!

  Everyone’s lab is different in terms of how many samples per day are processed, but they all share the common pain point of sample preparation. Some samples like blood and plasma need a significant amount of prep to remove proteins, phospholipids, and salts, whereas labs running urine or drinking water samples can “get by” […]

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 […]

How do I Replace my LC Tubing?

For those that are experienced with LC, you probably have this all figured out.  If that is the case, this might serve as a good introduction to Restek products that you can use for this.  For those that are newbies to liquid chromatography, welcome and I hope you find this useful! The best way to […]

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 […]