A rapid method using molecular imprinted polymers (MIPs) as solid phase extraction (SPE) sorbent in pretreatment and electrospray mass spectrometry (EIMS) were investigated to separate and determine trace amount of four main catechins, such as epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG), and epigallocatechin gallate (EGEG) respectively in tea samples. MIPs for EC (EC-MIPs) were prepared using methacrylic acid (MAA) as a monomer, ethylene glycol dimethacrylate (EDMA) as a cross linker, and azo-bis-isobutyronitrile (AIBN) as an initiator by UV radical polymerization method; and EC-MIPs were used as SPE sorbents (EC-MIPs-SPE) for selectively trapping and preconcentrating four catechins from eluate, and were then analysed by EIMS. The results showed EC-MIPs-SPE could selectively recognize catechins. Its binding capability and selectivity for catechins were better than that of caffeine and theophylline. The optimal extraction protocol was to load samples in the aqueous phase (v/v), to wash with 50% methanol and to elute with methanol containing 1% acetatic acid. Under above conditions, the interference of caffeine was eliminated to 94.2%, and of theophylline, 100%. The relative intensity was 12.1%, 8.2%, 35.4%, and 45.7% for EC, EGC, ECG, and EGCG respectively.
GAN Ning
,
LI Rong-sheng
,
CHEN Ya-dong
,
XU Wei-Ming
,
CAO Yu-ting
. Determination of Four Tea Catechins Content with Molecular Imprinting -SPE Extraction and Electrospray Mass Spectrometry[J]. Journal of Tea Science, 2009
, 29(3)
: 231
-235
.
DOI: 10.13305/j.cnki.jts.2009.3.009
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