Archive for the ‘Troubleshooting’ 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 […]

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: […]

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 […]

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 […]

Quadrupole Scan Speed and the 8270 Instrument Checkout Mix

In my last blog (here), I promised an update on the impact of the detector scan speed on the tailing factor. I had speculated that a pentachlorophenol tailing factor value of 0.94 was more likely < 1.0 because of the scan rate, rather than column overload. The examples I put forward here were collected on […]

It May be Hot Outside, but Your Headspace Analysis Can Still Suffer from the Cold

Summer days are my favorite – hot, sunny, and full of fun. But one thing that’s really not fun is trying to track down contamination and/or carryover in your headspace-GC (HS-GC) system. I get questions about this topic pretty regularly, so I thought I would post a blog on the most common culprit for contamination […]

Think you must use RFID-tagged lamps? Think again!

The recent addition of Radio Frequency Identification tags (RFID tags) to detector lamps allows automatic reference and usage data collection to your system software. This is convenient but comes at a cost: up to 40% more for an OEM-tagged lamp compared to a Restek replacement lamp. At the time of the writing of this blog […]

Is it OK to use THF (tetrahydrofuran) on my HPLC?

Well, it might be. In the early days of HPLC, THF was commonly used as a mobile phase solvent. It has eluting strength similar to acetonitrile, but just slightly stronger. Since it technically is an ether and is very miscible with water, it is sometimes useful with reverse phase HPLC. It also provides additional options […]

Split Injection Makes for Easier Polar Solvent GC Work versus Splitless Injection

As anyone who’s doing QuEChERS knows, analyzing acetonitrile extracts on nonpolar GC columns (like Rxi-5ms, e.g.) using splitless injection can be problematic because of the classic solvent – stationary phase mismatch.  To avoid split peaks we usually have an initial GC oven temperature slightly above the 82°C boiling point of acetonitrile (MeCN), but this causes tailing […]

More Technical Service “Red Flags” – LC

This post is the second of its kind pertaining to LC analysis, all of which are an extension of a series pertaining to “Red Flags” for GC analysis. These are situations and symptoms that tell us in the Tech Service group that something is just not right. As we discussed in the first post, Technical […]