Chemical and Engineering News has a report about a new Chemical Research in Toxicology paper that outlines how 
Thin Layer Chromatography is used to differentiate between a potent carcinogen found in diesel exhaust (3-nitrobenzanthrone or 3-NBA) and 2-NBA, which is largely the product of a nitration reaction that happens spontaneously in the atmosphere.
Here's an excerpt:
The team incubated each isomer with DNA and a variety of enzymes, and then used thin layer chromatography to determine the extent to which the DNA had been altered. Because 2-NBA did not form potentially harmful DNA adducts, the researchers determined that it is not a substrate for enzymes that activate 3-NBA toward DNA. In experiments with intact human liver cells, 3-NBA again generated DNA adducts, whereas 2-NBA did not.
Click Here to read the article.
The new issue of LCGC's "The Column" features a great 
cover story on Thin Layer Chromatography. The article, written by Analtech Technical Director Ned Dugan, explores the many ways TLC is being used.
The article focuses on some key examples:
- Fighting the Scourge of Counterfeit Medications
- Protecting Infants from Patulin Contamination
- Identifying a new nucleotide in human DNA
- Identifying the H1N1 Virus
- Use in Forensic Science
Click Here to see the entire issue.
We first mentioned this discovery here a couple of weeks ago, and just wanted to offer a few more details now that the paper by Skirmantas Kriaucionis and Nathaniel Heintz has been published.
Despite the importance of epigenetic regulation in neurological disorders, little is known about neuronal chromatin. Cerebellar Purkinje neurons have large and euchromatic nuclei, whereas granule cell nuclei are small and have a more typical heterochromatin distribution. While comparing the abundance of 5-methylcytosine in Purkinje and granule cell nuclei, we detected the presence of an unusual DNA nucleotide. Using thin-layer chromatography, high-pressure liquid chromatography, and mass spectrometry, we identified the nucleotide as 5-hydroxymethyl-2'-deoxycytidine (hmdC). hmdC constitutes 0.6% of total nucleotides in Purkinje cells, 0.2% in granule cells, and is not present in cancer cell lines. hmdC is a constituent of nuclear DNA that is highly abundant in the brain, suggesting a role in epigenetic control of neuronal function.
Click here to read more from Science.
From our friends at GenomeWeb.com:
Two researchers from Rockefeller University have identified a new nucleotide...
While evaluating 5-methylcytosine levels in two types of mouse brain cells, the team detected a nucleotide that they could not identify. When they looked more closely at this nucleotide using thin layer chromatography, high pressure liquid chromatography, mass spectrometry, and other approaches, the researchers discovered that they were dealing with 5-hydroxymethylcytosine, a form of methylated cytosine found stably in bacterial viruses.
Their subsequent experiments suggest the nucleotide is enriched in brain cells but apparently absent from several other cell types. Based on these findings, the researchers speculated that 5-hydroxymethylcytosine may contribute to epigenetic regulation, particularly in neurons.
Click Here to read more from GenomeWeb.com
Excerpts from a paper posted on the U.S. National Library of Medicine and the National Institutes of Health web site 
titled:
TLC-based detection of methylated cytosine: application to aging epigenetics
5-Methylcytosine (m(5)C) has a plethora of functions and roles in various biological processes including human diseases and aging. A TLC-based fast and simple method for quantitative determination of total genomic levels of m(5)C in DNA is described, which can be applicable to aging research with respect to rapid and high throughput screening and comparison. Using this method, an example of the analysis of global alternations of m(5)C in serially passaged human skin fibroblasts is provided, which shows age-related global hypomethylation during cellular aging in vitro.
Click Here to access the paper.