A method for increasing the precision of isotope ratio analysis on a Quadrupole ICP-MS based on measurements of lead and strontium

Strontium carbonate precipitation as a sample preparation technique for isotope ratio analysis of Sr in mineral water and wine by quadrupole‐based inductively coupled plasma mass spectrometry

“…The isotope ratio measurements were performed and evaluated by the Concentration‐Gradient‐Method (CGM), as described by Dronov and Schram, where the measured signal intensities of different isotope concentrations are plotted against each other. A straight line is obtained with the slope characterising the isotope ratio.…”

“…Following the measurement sequence presented by Dronov and Schram measurement using the CGM was performed with a descending concentration series without rinsing steps between the concentration step changes. Rinsing was only performed between the different samples.…”

“…In the case of a successive reduction of the sample concentration, the surfaces are washed out during the measurement and this thus reduces the memory‐effect possibly affecting the measurement of the subsequent sample. In addition, the plasma is more stable as there is less disruption by air bubbles in the sample introduction system . The decreasing concentration steps were set to 10.0 μg / L to 0.0 μg / L dilutions of the samples in 2.0 μg / L steps.…”

Concentration‐Gradient‐Method for sulphur and strontium isotope ratio determination by quadrupole‐based inductively coupled plasma mass spectrometry in gypsum

“…Many groups have tried to characterise and improve the precision of isotope ratio determination with ICP‐QMS . For example, Monna et al described the optimum integration times of measured isotopes depending on their isotopic composition for lead (Pb) and strontium (Sr).…”

“…The use of a concentric nebulizer with liquid samples requires a change in the type of measurement. Dronov and Schram described the concentration‐gradient‐method (CGM) where a step‐wise change in well‐defined concentrations is used for the calculation of isotope ratios using a linear regression model. With such a modification of the measurement it is possible to validate the data points more precisely and accurately than with the conventional ICP‐MS data evaluation approach.…”