An Improved Procedure for Wet Oxidation of the 14C NBS Oxalic Acid Standard
Issue Date
1977-01-01Keywords
acidswet methods
chemical analysis
methods
C 14
carbon
isotopes
radioactive isotopes
C 13 C 12
stable isotopes
absolute age
geochemistry
processes
Metadata
Show full item recordCitation
Valastro, S., Land, L. S., & Varela, A. G. (1977). An improved procedure for wet oxidation of the 14C NBS oxalic acid standard. Radiocarbon, 19(3), 375-382.Publisher
American Journal of ScienceJournal
RadiocarbonAdditional Links
http://radiocarbon.webhost.uits.arizona.edu/Abstract
An improved procedure for wet combustion of 14C NBS oxalic acid standard has been devised which gives consistent high carbon yields and average delta-13C values of -19.1 per mil. The principal cause of fractionation in earlier attempts to prepare CO2 by the wet oxidation method was the inexact nature of the end-point. The new procedure employs a chocolate-brown end-point by adding 5ml more of the sulfuric acid-potassium permanganate solution after the initial reddish brown end-point is reached. The sulfuric acid-potassium permanganate solution is added to the NBS oxalic acid in a steady drop-wise flow, heat is applied to the generating apparatus, and a cycling technique is utilized to collect the CO2. Fifteen samples of the NBS oxalic acid were processed. The per cent carbon yields range from 98.8 to 100.9% with an average of 99.7% and an average delta-13C of -19.12 per mil. The results obtained by this procedure are much more consistent than previous results obtained in several laboratories by direct combustion.Type
Articletext
Language
enISSN
0033-8222ae974a485f413a2113503eed53cd6c53
10.1017/S0033822200003696