Dating of ivory from 20th century by determination of 14C by the direct absorption method

Dating ivory by determination of , and

“…14 C and 90 Sr were determined as described in Refs. [2,5]. The range of elution for 90 Sr was determined by the g-emitter 85 Sr by using varying masses of calcium (1.0 g, 1.5 g, 1.75 g, 2.0 g, 2.25 g, 2.5 g and 3.0 g) to check whether the range of elution differs.…”

“…Combustion of the samples was carried out first as described by Schmied et al [2] and Brunnermeier et al [5] in order to determine 14 C. The remains of this combustion were completely incinerated in the second step. Then, the ashed samples were analysed for calcium by photometry.…”

Bomb-curve radiocarbon measurement of recent biologic tissues and applications to wildlife forensics and stable isotope (paleo)ecology

“…CO 2 was cryogenically purified, graphitized, and measured for 14 C by AMS at the University of Arizona. Stable carbon isotope ratios are reported as δ values relative to the Vienna Pee Dee Belemnite (VPDB) standard using permil (‰) notation, where δ 13 C = (R sample / R standard − 1) × 1,000, and R sample and R standard are the 13 C/ 12 C ratios in the sample and in the standard, respectively. The δ 13 C values are used for fractionation corrections of 14 C.…”

“…Geyh (5) found human bone collagen and animal leather are less suitable for bomb-curve dating than hair, which could be used to determine age of death within about 2 y. Forensics research to determine year of birth has focused primarily on human tooth enamel and dentin (6-10), although proteins in the crystalline portions of eye lenses also provide accurate birth-year estimates (11). Several studies have explored the use of radiocarbon to date tusk ivory (4,12,13) but offer only limited data and, in some cases, lower precision than accelerator mass spectrometry (AMS) methods (13).…”