Solution to titration endpoint challenge

Solution to half-titration challenge.

Solution to phenylbutazone purity challenge.

In the last 15 years NMR has become a reference technique for the determination of purity for organic standards containing NMR active nuclei [1, 2]. The puzzle proposed for this Analytical Challenge was focused on the use of 1H-NMR for the characterization of a phenylbutazone standard. Such material was purchased from Sigma-Aldrich and analyzed in parallel by HPLC-UV and 1H-NMR. Initially, appl...

Solution to spectroscopy challenge 8.

Malic acid was first isolated by Carl Wilhelm Scheele from apple juice in 1785. Scheele was born in 1742 in Stralsund. The German seaport of Stralsund is situated on the southern coast of a sound of the Baltic Sea that separates the island of Rügen from the mainland. This small town remained under Swedish control until 1815, when it became a part of the Prussian Province of Pomerania. Thus, Sch...

A Possible Solution to the Tritium Endpoint Problem

Scalar or right-chiral interaction currents may be expected to produce a neutrino coupled to the electron which is different from, and perhaps even orthogonal to, that coupled to the electron by the standard model weak interaction. We show that, using reasonable parameter values for such additional interactions, it is possible to generate a spectrum which, if analyzed in the manner commonly emp...

Titration of alkyllithiums with a simple reagent to a blue endpoint

Reaction of readily available N-benzylbenzamide (I) with a slight excess of BuLi produces a deep blue dianion. Under suitable conditions (THF, -40*(2), 1 may be used as a stoichiometric reagent to titrate n-BuLl, s-BuLi, and t-BuLi with good precision. Less reactive alkyllithiums (MeLi and MeLi, LiBr), aryllithiums, and LDA may be titrated at higher temperatures ( 20 to 0°C). Titres are compara...