Enantioselective separation and electrochemical sensing of D- and L-tryptophan at ultratrace level using molecularly imprinted micro-solid phase extraction fiber coupled with complementary molecularly imprinted polymer-fiber sensor

Highly efficient enantioselective separation and quantitative recoveries of D- and L-tryptophan in aqueous and real samples can be achieved, with a monolithic molecularly imprinted polymeric fiber that serves both for micro-solid phase extraction and ultratrace sensing, without any false-positive (nonspecific) contribution and cross-reactivity, in the range of 0.15-30.00 ng mL(-1) with detection limit as low as 0.0261 ng mL(-1) (relative standard deviation = 0.64%, signal/noise = 3). The proposed method combining molecularly imprinted micro-solid phase extraction fiber and a complementary molecularly imprinted polymer-carbon composite fiber sensor is proven to be useful for clinical diagnosis of stress-related diseases caused by acute tryptophan depletion. (C) 2010 Elsevier B.V. All rights reserved.