Novel silver-tubing method for quantitative introduction of water into high-temperature conversion systems for stable hydrogen and oxygen isotopic measurements

A new method to seal water in silver tubes for use in a TC/EA (thermal conversion/elemental analyzer) reduction unit using a semi-automated sealing apparatus can yield reproducibilities (1 standard deviation) of δ2H and δ18O measurements of 1.0‰ and 0.06‰, respectively. These silver tubes containing reference waters may be preferred for the calibration of H- and O-bearing materials analyzed with a TC/EA reduction unit. The new sealing apparatus employs a computer-controlled stepping motor to produce silver tubes identical in length. The reproducibility of the mass of water sealed in tubes (in a range of 200–400 µg) can be as good as 1%. Approximately 99% of the sealed silver tubes are satisfactory (leak free). Although silver tubes [...]