B ECAUSE barbiturates are relatively easily available and much used drugs, specimens from suspected cases of poisoning are frequently submitted to the laboratory for routine chemical examination. Since their urinary excretion begins early (because they are quickly absorbed), they can often be identified 1-2 hours after administration. The specimen of choice for examination is therefore the urin...

A micromethod for detecting and determining various porphyrins extracted from biological materials, especially nervous tissues (I), is needed. The technique of filter paper chromatography by Consden, Gordon, and Martin (a), with modification by Williams and Kirby’s capillary ascent (3), has been applied to the problem in this study. The recent paper by Nicholas and Rimington (4) on partition ch...

Chromatography is a common technique for separating chemical substances. The prefix “chroma,” which suggests “color,” comes from the fact that some of the earliest applications of chromatography were to separate components of the green pigment, chlorophyll. You may have already used this method to separate the colored components in ink. In this experiment you will use chromatography to separate...

The classical procedure for the identification of hemins as prosthetic groups is to isolate the hemins, convert them into porphyrin esters, and identify the esters by their spectra and melting points. This procedure usually requires considerable amounts of material, gives poor yields, and the melting points have not always been definitive (1). Chromatographic methods have aided in establishing ...

Knight has recently studied the movement of nineteen amino acids and thirty-four peptides on paper chromatograms (1). It seemed possible that from these data a general method of calculating the movement of a peptide relative to the movement of the solvent front (RI) could be obtained. Such calculations have been attempted in a simple, straightforward manner without utilizing any special factors...

Anyone who has ever played on grass or had an unplanned encounter with a bush knows that plants contain pigments which adhere to varying degrees to fabric (and skin!). The fact that a small industry has risen up in aid of attempts to remove stains like these and many others shows that not all of the molecules can be treated in the same way if their removal is desired. Part of the reason behind ...

Knight has recently studied the movement of nineteen amino acids and thirty-four peptides on paper chromatograms (1). It seemed possible that from these data a general method of calculating the movement of a peptide relative to the movement of the solvent front (RI) could be obtained. Such calculations have been attempted in a simple, straightforward manner without utilizing any special factors...