Archive for the ‘Tips & Tricks’ Category

Troubleshooting Injection Volume Variation in the Concurrent Solvent Recondensation – Large Volume Sample Injection Technique

I’ve started receiving a number of questions about the large volume injection technique called Concurrent Solvent Recondensation – Large Volume Sample Injection. Most recently, a question came through the Tech Service group about injection volume variation. I had encountered a similar problem when working on the 50 µL injection for the combined 1,4-Dioxane and Nitrosamines (EPA […]

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 […]

Utilizing Restek Reference Standards for Residual Solvent Testing

Restek manufactures several different residual solvent standards.  These can be used for testing according to USP <467>, the EP monograph, or other residual solvent assays, such as medical cannabis testing.   The calculations involved for the use of these standards has led to questions for our technical team.  This post should help provide guidance for their […]

Fluorophenyl LC Phases- what you should know

They may be called PFP, PFPP, pentafluorophenyl, fluorophenyl or F5 phases. What they all have in common is the structure shown above (the pentafluorophenyl  group) attached to the silica particles. Most modern phases contain a propyl spacer between the above group and the silica, so that the phase looks something like this:     A […]

Need parts for your Agilent 1100? HP 1050? Restek has you covered.

As of May 31, 2015, 1100 Series HPLC systems were categorized “End of Guaranteed Support” (EGS) by Agilent. Agilent would prefer it if you purchased a new system from them, but 1100 HPLCs are dependable workhorses. Why not keep them running with instrument replacement parts from Restek? Check out our selection, easily sorted by instrument and module: […]

Which guard cartridges and holders go with which LC analytical columns?

As our family of LC products has grown, so have our choices for columns and accompanying guard cartridges. Here is a handy chart to show which guard holder and guard cartridges were intended for use with each type of analytical column. Please feel free to click the links to access each group of products on […]

Leak Detector Lithium Ion Battery

Lithium ion batteries have been in the news quite a lot recently, and not all of it has been positive.  There have been numerous incidents of different products from airplanes to hoverboards to mobile phones catching fire during charging or operation.  These problems occur when there has been damage to the cells’ structure or to the […]

What can I use as a cap for my mobile phase bottles?

Our choices for mobile phase bottle tops are based primarily on two different products. The first product is the Hub-Cap Bottle Top, catalog #26541. This is designed to fit a 4-Liter solvent bottle. :     The body (also called insert) of the Hub-Cap Top is cap is made of inert PTFE and has three […]

Quadrupole Scan Speed and the 8270 Instrument Checkout Mix – Part II – The DFTPP Evaluation

Yesterday’s blog gave an overview of how choosing the wrong scan speed could be detrimental to the tailing factor evaluation. Before someone asks, I thought we’d spend today looking at the impact of scan speed on the decafluorotriphenylphosphine (DFTPP) tune evaluation. I know I’ve covered this before, but here are the tuning criteria from EPA […]

An introduction to the benefits of using split injection when performing semivolatiles analysis by 8270D – the instrument checkout mix

This blog is part of a series; the previous installments can be found here and here. We have mentioned several times that the reduced residence time resulting from the fast sample transfer that occurs during a split injection reduces in-inlet degradation and adsorptive loss. Proof of this can be seen in the first run of […]