Rapid Quantitative Determination of Isoprene Monomer in Living Taraxacum kok-saghyz by Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry

Taraxacum kok-saghyz (TKS) is rich in natural rubber (NR), a natural organic macromolecular compound composed of cis-1,4-polyisoprene, and may become the second NR-bearing plant for biochemical engineering development. In this paper, a rapid and quantitative ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was established for determination of macromolecular biosynthesis substrate (dimethylallyl pyrophosphate, DMAPP) and initiator (farnesyl pyrophosphate, FPP) contained in TKS. A Kromasil C₁₈ chromatographic column was used for separation, and the multi-reaction monitoring mode (MRM) of triple quadrupole mass spectrometry was used for detection. Quantification was performed by external calibration method. The results showed that the limit of detection (LOD) and the limit of quantitation (LOQ) of DMAPP were 2.42 μg/L and 7.26 μg/L, respectively, and the LOQ and the LOD of FPP were 1.02 μg/L and 3.05 μg/L, respectively. At a concentration of 1—1000 μg/L, both analytes had good determination coefficients (> 0.999) of calibration curve. The recoveries of DMAPP and FPP were between 99.0% and 117.1%. In real samples detection, the contents of DMAPP and FPP in TKS samples were between 23.32—82.77 μg/L and 12.03—85.67 μg/L, respectively. Thus, this approach is a reliable method to quantify DMAPP and FPP in TKS.