Semi-automated direct elution of dried blood spots for the quantitative determination of guanfacine in human blood.

Toshiyuki Fukao, Hoan Thi Nguyen, Nhan Thu Nguyen, Dung Chi Vu, Ngoc Thi Bich Can, Anh Thi Van Pham, Khanh Ngoc Nguyen, Hironori Kobayashi, Yuki Hasegawa, Thao Phuong Bui, Kary E. Niezen-Koning, Ronald J.A. Wanders, Tom de Koning, Liem Thanh Nguyen, Seiji Yamaguchi, Naomi Kondo

Index: Bioanalysis 4(12) , 1445-56, (2012)

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Abstract

Direct analysis of dried blood spot (DBS) samples was investigated using a prototype semi-automated robotic device that allows the direct elution of sample spots from a DBS paper card to an online SPE cartridge. The eluted SPE samples were analyzed with high-performance LC-MS/MS.A LLOQ of 0.01 ng/ml was achieved with a linear calibration range from 0.01 to 25 ng/ml. Optimal performance data were obtained from spotting the internal standard solution on the card before blood spotting. Internal standard addition from the system injector loop produced intra-assay inaccuracy of -9.0-7.3% and precision of 1.3-8.2%, and inter-assay inaccuracy of -3.5-3.9% and precision of 4.4-8.7%.Results demonstrated the feasibility of a semi-automated online rapid direct elution method that avoids manual extraction for DBS sample analysis using the online DBS-SPE system coupled to LC-MS/MS.