New National Bureau of Standards Contemporary Carbon-14 Standards

Abstract

In 1957 the National Bureau of Standards (NBS) agreed, at the request of James R Arnold, to store and distribute an oxalic acid contemporary carbon-14 standard. In 1978 stocks of this standard were practically gone. We approached Chas Pfizer and Company, Inc, which had provided the original 1000 pounds of oxalic acid to Dr Arnold to see if they could provide another one-batch lot of 1000 pounds of oxalic acid to replace the old standard. This they did generously, at no cost to NBS. The oxalic acid was prepared by fermentation of French beet molasses from the 1977 spring, summer, and autumn harvest using Aspergillus niger var. The acid was separated from the broth as the insoluble calcium salt and reconverted to free acid using sulfuric acid. The free acid was then crystallized, redissolved, filtered, recrystallized, and dried.