Category Archives: Thin Layer Chromatography

NAOSMM in Boise

The National Association of Scientific Materials Managers trade show started this morning in Boise, Idaho.

NAOSMM in BoiseWe’re excited to see several old friends and make quite a few new friends.

Many are thrilled to see our new color HPLC columns and learn about our propietery color columnsSAM chemistry.

Several supply managers have reported to us that they started using our TLC plates after meeting us atNAOSMM crowd a previous NAOSMM show and how satisfied they are with both our products and our customer service.

It’s a great experience for us to be able to meet so many of our customers, share stories, and explore new applications for chromatography.

More information and videos coming tomorrow!

Thin Layer Chromatographic Analysis of Counterfeit Drugs

Joseph Sherma is the John D. and Frances H. Larkin Professor Emeritus of Chemistry at Lafayette College, Easton, Pennsylvania. Professor Sherma has taught courses in analytical chemistry for more than 40 years, was head of the chemistry department for 12 years, and continues to supervise research students at Lafayette College. He is author and coauthor of over 600 papers and the author, coauthor, editor, and coeditor of over 60 books and manuals in the areas of analytical chemistry and chromatogEncyclopedia of Chromatographyraphy.

Professor Sherma recently authored the article, “Thin Layer Chromatographic Analysis of Counterfeit Drugs” – which is featured in the Encyclopedia of Chromatography, Second Edition.

Here’s a look at the Abstract:

Economical and reliable thin layer chromatographic (TLC) methods for rapid screening of counterfeit drugs that can be carried out by analysts in the laboratory or in the field by inspectors with limited analytical expertise using portable kits, with standard reference tablets to eliminate weighing, are described. Separations are performed on silica gel layers containing fluorescent indicator; separated spots are detected under ultraviolet lamps and with iodine detection reagent. Development and iodine detection are carried out in polyethylene bags, glass jars, or closed TLC tanks. Sample spots are compared with reference standards developed on the same layer to identify the ingredients and determine if their content is within the specification range.

Click Here to find out how to obtain the paper.

Thin Layer Chromatography and HPLC featured in quality standards for Dietary Supplements

The U.S. Pharmacopieal (USP) Convention has just released a first-of-its kind collection of standards designed to assist dietary supplements manufacturers in providing quality products to consumers.Dietary supplements

The USP Dietary Supplements Compendium (DSC) is a comprehensive resource containing quality specifications (identity, strength, purity, and performance characteristics) of more than 500 dietary supplements and ingredients. In addition to these standards, the DSC includes general and regulatory information, guidance documents, appendices, and macro/microscopy, thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) full-color images that greatly simplify the analysis of ingredients of botanical origin—making it a central repository of necessary information for dietary supplements manufacturers.

The DSC serves as a tool for manufactures in:

  • Developing, manufacturing and testing new products;
  • Qualifying raw materials;
  • Preparing for international quality control and cGMP audits;
  • Setting and validating standard operating procedures;
  • Collecting in-process and batch-release tests; and
  • Accurately packaging, labeling and storing products.

 Click Here for more information from USP.

Thin Layer Chromatography used to detect counterfeit medication in India

Excerpts from a research article published at Plosone.org:TLC Chart

Pilot Study of Essential Drug Quality in Two Major Cities in India

India is an increasingly influential player in the global pharmaceutical market. Key parts of the drug regulatory system are controlled by the states, each of which applies its own standards for enforcement, not always consistent with others. A pilot study was conducted in two major cities in India, Delhi and Chennai, to explore the question/hypothesis/extent of substandard and counterfeit drugs available in the market and to discuss how the Indian state and federal governments could improve drug regulation and more importantly regulatory enforcement to combat these drugs.

Random samples of antimalarial, antibiotic, and antimycobacterial drugs were collected from pharmacies in urban and peri-urban areas of Delhi and Chennai, India. Semi-quantitative thin-layer chromatography and disintegration testing were used to measure the concentration of active ingredients against internationally acceptable standards. 12% of all samples tested from Delhi failed either one or both tests, and were substandard. 5% of all samples tested from Chennai failed either one or both tests, and were substandard.

Read the entire research paper by clicking here.

An Apple A Day – minus the patulin – how Thin Layer Chromatography provides faster, cheaper answers

Here’s an excerpt from Scirus.com about using Thin Layer apple with patulinChromatography for the analysis of patulin in apple juice (emphasis added) :

Researchers from Brazil developed a rapid, simple and economical method using thin-layer chromatography quantification via fluorescence images from a UV lamp, for the determination of patulin in apple juice concentrate

Why it matters

According to the authors, patulin is a mycotoxin produced by certain species of Penicillium, Aspergillus and Byssochlamys. In previous research studies, liquid chromatography has been used for patulin determination in clear and cloudy apple juices, apple puree and apple-based products intended for infants. Methods such as gas and liquid Thin Layer Chromatography detects patulinchromatography have very low detection limits, but both techniques require sophisticated and costly equipment, extensive cleanup procedures and high purity solvents. Thin-layer chromatography (TLC) is a fast, cheap and efficient method of separation and identification of many mycotoxins. By coupling a two-dimensional charge coupled device with thin-layer chromatography, the entire TLC can be imaged in a single exposure, yielding rapid quantification in shorter analysis time than slit scanning densitometers.

 Click Here for the full Abstract.

Thin Layer Chromatography used to weed out counterfeit medication

We’ve posted on this subject before, but wanted to offer fake drugsmore on the subject from our friends at Australia’s On Line Opinion, where Roger Bate has written about tools to fight fake drugs:

Poor quality medicines are pervasive across Africa. The WHO reports that more than 30 per cent of medicines on sale in many African countries are counterfeit, with some pills containing nothing more than chalk or water.

The German Pharma Health Fund’s “Minilab” uses thin layer chromatography, disintegration and simple dye tests to help weed out the worst-quality products. Generally, a product will “pass” the Minilab test if it contains 80 per cent or more of the labelled active ingredient.

 Click Here to read the entire piece.

 

Thin Layer Chromatography used in plant defense research

Anti-herbivore Structures of Paulownia tomentosa: Morphology, Distribution, Chemical Constituents and Changes During Shoot and Leaf Development:

Background and Aims: Recent studies have shown that small structures on plant surfaces serve ecological functions such as resistance against herbivores. The morphology, distribution, chemical composition and changPaulownia tomentosaes during shoot and leaf development of such small structures were examined on Paulownia tomentosa.

Methods: The morphology and distribution of the structures were studied under light microscopy, and their chemical composition was analysed using thin-layer chromatography and high-performance liquid chromatography. To further investigate the function of these structures, several simple field experiments and observations were also conducted.

Click Here to read more.

Doing Thin Layer Chromatography at home

Sean Michael Ragan at Makezine.com recently posted a great post about Thin Layer Chromatography in the kitchen – here’s some excerpts:

During my six-odd years as a graduate organic chemist, probably the cheapest, most powerful, and most commonly used analytical laboratory technique in my bag of tricks was thin-layer chromatography…

[another] common reason for performing separations is analytical: You want to get an idea of how many compounds are in there and whether or not one of them is compound “X.” Thin-layer chromatography lets you do this, on a bench-top, with a few cents worth of materials and a few minutes of time. It’s unbelievably powerful for such an inexpensive technique.

 Click here to read the complete post.

 

Thin Layer Chromatography and DNA – the story continues

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.

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