By ALFRED F. ZAPPALA and CHARLES A. SIMPSON
T h e described method involves separation of panthenol or pantothenate from its decomposition products and subsequent alkaline hydrolysis. The hydrolysis products are chlorinated and iodine is liberated by addition of an iodide solution. The yellow color formed is stabilized and determined colorimetrically. This method is Fomparable in time to existing methods and has the advantage of increased sensitivity. The colorimetric part of the procedure is also applicable to other N-H containing compounds.
ONFRONTED WITH the problem of determining c panthenol in a multivitamin preparation,'
the authors initially tried the naphthoquinone method of Schmall and Wollish (1). In this method, ion exchange resins and adsorbents are used for the removal of interfering substances as well as the hydrolysis products of panthenol and pantothenates. Subsequently, the molecule is cleaved with strong base and t h e resultant 0alanol is coupled with 1,2-naphthoquinone-4sulfonate and measured colorimetrically .
When the multivitamin preparation used in most of our work was subjected to t h e method just described, the solution darkened considerably and to varying degrees during the hydrolysis step.
T h e reason for this was determined t o be the high concentration of sugars (15 per cent) present in this preparation.
It was thought that a more sensitive method such as the ninhydrin procedure of Schmall and Wollish (loc. cit.), would tend to circumvent t h e problem of high sugar concentration. This method requires the use of cyanide and consequently was felt to be undesirable as it would necessitate some rather involved safety regulations.
T h e purpose of the present work was to eliminate this interference. One approach was to devise an additional separation. Another approach was to use a more dilute sample solution in conjunction with a more sensitive color reaction, inasmuch as it is known that the chromatographic column is capable of removing moderate amounts of sugars.
EXPERIMENTAL
Separation from Sugars.-Panthenol was quantitatively extracted from the powdered sample with