Development of the Isotope Analysis Technique for Inorganic Trace Elements using Laser Ablation Assisted Resonance Ionization Mass Spectrometry (LA-RIMS)

Abstract

We have developed and assessed LA-RIMS as the isotope analysis method for trace inorgac elements in agricultural products. We used magnesium isotope analysis to verify that LA-RIMS had the capability to identify the production areas with the required precision of 0.3%. We demonstrated direct measurements of trace strontium (sub ppm level) in brown rice and confirmed that the isotope analysis precision was improved through the signal intensity enhancement by increasing the ablation power and expanding the laser spot. For the present system, we estimated the strontium isotope ratio of ⁸⁷Sr/⁸⁶Sr to be 0.69±0.10 (14%). We concluded that the direct isotope analysis for trace inorganic elements such as strontium in brown rice using LA-RIMS had an advantage under the serious situation of isobaric interference and had sufficient capability to identify agricultural production areas.

KEYWORDS:

• isotope analysis
• trace analysis
• resonance ionization mass spectrometry
• laser ablation
• origin determination
• brown rice
• strontium isotope