Precise determination of the strontium isotope ratios in wine by inductively coupled plasma sector field multicollector mass spectrometry (ICP-SF-MC-MS)

The Sr-87/Sr-86 isotope ratio of wine reflects that of the soil on which the vine is grown and is characteristic of the geographical origin of wine. A method based on ICP-MS using a sector field mass analyser with a multicollector able to reach the precision required for the discrimination of different wines (<0.005%) was developed. Strontium was separated from Rb (to avoid the Sr-87/Rb-87 isobaric interference) and the Sr-rich fraction was nebulized into the ICP. Precision values of 0.002-0.003% were routinely measured. The accuracy of the method, evaluated by analysis of the NIST SRM 987 (SrCO3, isotopic), was 0.02%. The analysis of 11 wines of different origins showed a clear difference between wines produced on basaltic, mixed and granitic soil areas.