567178 EA-IRMS elemental analyzer-isotope ratio mass spectrometry 60 567173 EA-IRMS elemental analyzer-IRMS 2 567176 EA-IRMS developed an isotope ratio mass spectrometric 1 567172 EA-IRMS elemental analyser in connection with a gas isotope mass spectrometer 1 567175 EA-IRMS Elemental Analysis-IRMS 1 567174 EA-IRMS elemental analyzer in combination with stable isotope ratio mass spectrometry 1 567177 EA-IRMS elemental analyzer-isotope ratio MS 1