Formation of cinnamaldehyde dimethyl acetal in methanol during analysis

As a principal compound of cinnamon essential oil, cinnamaldehyde has been used as marker for the quality control and its oil. During HPLC analysis, reaction product was observed in methanol solution reference standard. This isolated identified to be dimethyl acetal based on spectroscopic analysis. Although dimethylacetalization MeOH recorded many literatures, this is first report about normal analysis procedure. Further studies suggested that could affected by parameters, including concentration, storage temperature, light illumination. Those results stock standard should not prepared with methanol, extraction procedure heating sample might accelerate acetalization cinnamaldehyde. The use during carefully considered.