Determination of delta2H and delta18O in saline oil-associated waters: the question of simple vacuum distillation of water samples prior to isotopic analyses.
The paper deals with analytical and procedural aspects of delta18O and delta2H determination in saline oil-associated waters. The main objective of the study was to show experimentally the qualitative and quantitative applicability of the simple vacuum distillation of saline oil-associated waters while routine procedures of water isotopic analyses are applied. Additionally, two standard off-line techniques of delta2H determination in water - the zinc and the chromium method - have been compared. Each time a typical isotope salt effect has been tracked on the Dead Sea water. The results clearly show that application of the simple vacuum distillation improve the accuracy and reproducibility of delta2H determinations, especially in chromium off-line technique which appeared to be more sensitive to water salinity. The simple vacuum distillation does not improve the quality of delta18O determinations in the range of water salinities studied. Its application to high concentrated brines (for example, Dead Sea water) decreases the time of equilibration but still propagate the isotopic error connected with low water activity (in the case of 18O/16O ratio) and the incomplete water extraction from the remaining salts (in the case of 2H/1H ratio); in consequence, its time-consuming application seems to be baseless.
Institute of Geological Sciences Polish Academy of Sciences, Warsaw, Poland. adamp@twarda.pan.pl
Adam
A
Porowski
Peter
P
Kowski
D003903:Deuterium / Q000032:analysis*; D009821:Oils; D010103:Oxygen Isotopes / Q000032:analysis*; D012492:Salts; D014867:Water / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
D009821:Oils; D010103:Oxygen Isotopes; D012492:Salts; D014867:Water; D003903:Deuterium