Abstract: A method for simultaneous determination of 9 inedible pigments in capsanthin was developed by a quick, easy, cheap, effective, rugged and safe (QuEChERS) pretreatment method coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) under the multiple reaction monitoring (MRM) mode. Capsanthin samples were extracted with acetonitrile-water, and then sodium chloride was added for salting out. The extract was cleaned up using C18 sorbent before being analyzed by UPLC-MS/MS. Matrix effect in the method was between ?0.17 and 0.07. The limits of detection (LODs) and limits of quantitation (LOQs) were in the range of 0.2–1.5 ng/g and 0.6–5.0 ng/g, respectively, and good linearity was found in the concentration range of 0.2–8 ng/mL for basic orange II, basic orange 21, basic orange 22 and solvent yellow 34; and of 2–40 ng/mL for sudan I, sudan II, sudan III, sudan IV and rhodamine B chloride with correlation coefficients (R2) higher than 0.995 0. The average recoveries of the 9 inedible pigments at three spiked concentration levels were between 69.6% and 92.5%, with relative standard deviations (RSDs) between 2.8% and 8.5% (n =5). This method proved to be simple, rapid, accurate, reliable, and suitable for the detection of inedible pigments in large quantities of natural plant extract samples.

Key words: capsanthin, QuEChERS, ultra-high performance liquid chromatography-tandem mass spectrometry, inedible pigments, rapid detection