Archive for the ‘Miscellaneous’ Category

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 […]

How Dirty Are You? Part 5…Micropipette Tips

Pipettes are common tools for drawing and dispensing precise volumes in chemical, biological and medical labs. Thanks to the invention of micropipettes and other techniques, we don’t do mouth pipetting anymore. Positive displacement pipettes are particularly useful because the air gap in standard micropipettes are replaced by capillary pistons, which greatly improve the accuracy for […]

RIP Philae

The exact resting place of the Philae lander on Comet 67P/Churyumov-Gerasimenko has finally been pinpointed, in new photographs by the Rosetta orbiter. Rosetta did a close pass of the comet on September 2nd and the survey caught the first clear glimpse of Philae’s position.   I’m so proud that Restek was able to contribute columns […]

Impact of pH on Derivatization of Nitrophenol Compounds

Our goal of evaluating the Normalized French Environmental Method 12673 required testing the method’s ability to derivatize nitrophenols and alkylphenols in addition to the chlorophenols the method was designed for. Unfortunately, nitrophenols proved challenging to derivatize at low concentrations. In an effort to improve the derivatization of nitrophenols, we experimented with the pH of the […]

Improved Peak Symmetry as a Result of Derivatization of Phenols

Peak symmetry is important for determination and quantification of compounds. In order to create a symmetric peak, the compound must be able to elute all at more or less the same time. If a compound interacts with the column itself (ex: by temporarily adsorbing to the fused silica surface), it delays travel and effects peak […]

Nobel Laureate Talks and Restek Champagne Reception

From July 19th – 22nd 2016 Restek Corporation with the collaboration of the German Restek Office (Restek GmbH) attended the 39th ISEAC conference, organized from the “International Association of Environmental Analytical Chemistry” (IAEAC) at the Hamburg School of Food Science, lead by  Prof. Dr. Markus Fisher. The central subject of the ISEAC-39 conference is the innovative use […]

Hernanisms

Last Sunday, I was sitting in the garden, recapping the experiences of attending the scientific conferences I had the pleasure to visit during this year. One of the honoring sessions has left a quite inspiring impact on my mind. In the beginning of the year, I had the opportunity to listen to one of the […]

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 […]

Simple Analysis of Bile Acids by GC-MS

Bile acids are a group of steroidal acids with carboxyl and hydroxyl groups on the side. They are the major metabolic products of cholesterol. Bile acids play important roles as biomarkers for early diagnosis and therapeutic monitoring of many diseases, especially liver and intestinal diseases. For instance, high levels of intestinal bile acids, in particular, […]

Changes in Elution Order between Phenols and Phenyl Acetates

In order to determine contamination levels for phenols in water, the French normalized method, NF EN 12673, recommends an in-situ derivatization with acetic anhydride, followed by extraction with hexanes. The derivatization process (diagrammed in Figure 1) converts the phenolic compounds into phenyl acetates, which perform much better on GC/MS columns such as the Rxi-5Sil, due […]