Quantitative Detection of Natural Rubber Content in Eucommia ulmoides by Portable Pyrolysis-Membrane Inlet Mass Spectrometry

Eucommia ulmoides gum (EUG) is a natural polymer predominantly consisting of trans-1,4-polyisoprene. Due to its excellent crystallization efficiency and rubber-plastic duality, EUG finds applications in various fields, including medical equipment, national defense, and civil industry. Here, we devised a portable pyrolysis-membrane inlet mass spectrometry (PY-MIMS) approach to rapidly, accurately, and quantitatively identify rubber content in Eucommia ulmoides (EU). EUG is first introduced into the pyrolyzer and pyrolyzed into tiny molecules, which are then dissolved and diffusively transported via the polydimethylsiloxane (PDMS) membrane before entering the quadrupole mass spectrometer for quantitative analysis. The results indicate that the limit of detection (LOD) for EUG is 1.36 mu g/mg, and the recovery rate ranges from 95.04% to 104.96%. Compared to the result of pyrolysis-gas chromatography (PY-GC), the average relative error is 1.153%, and the detection time was reduced to less than 5 min, demonstrating that the procedure was reliable, accurate, and efficient. The method has the potential to be employed to precisely identify the rubber content of natural rubber-producing plants such as Eucommia ulmoides, Taraxacum kok-saghyz (TKS), Guayule, and Thorn lettuce.

Automated summary

A portable pyrolysis-membrane inlet mass spectrometry (PY-MIMS) approach was developed to rapidly and accurately identify the rubber content in Eucommia ulmoides gum. The method involves pyrolyzing the gum into small molecules, which are then diffusively transported for quantitative analysis. The results showed a limit of detection of 1.36 μg/mg and a recovery rate ranging from 95.04% to 104.96%. Compared to pyrolysis-gas chromatography (PY-GC), the average relative error was 1.153%, and the detection time was reduced to less than 5 minutes, demonstrating the reliability, accuracy, and efficiency of the procedure. This method has the potential to be used for precise identification of rubber content in natural rubber-producing plants.