Cam-based vibration-counter-balanced laser-induced fluorescence scanner for multiplexed capillary detection

• Published in: Talanta (Oxford) 2019-06, Vol.198, p.398-403
• Main Authors: Li, Guanbin, Wang, Shili, Zhu, Zaifang, Chen, Apeng, Liu, Shaorong
• Format: Article
• Language: English
• Subjects: Cam; Capillary array electrophoresis; Counter-balanced scanner; Laser-induced fluorescence scanner; Protein separation
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2019.01.128

Laser-induced fluorescence (LIF) rotary scanners have been successfully used for multiplexed capillary detection. However, these scanners have a limitation that the capillaries have to be assembled in a circular format, which can be inconvenient for certain applications. A linear LIF scanner works well for flat parallel capillary arrays, but motor accelerations/decelerations (for direction changes) and scanning head vibrations introduce high instrumental noises. The number of capillaries that can be scanned by a linear scanner is limited because of the above constraints. We have constructed a cam-based scanner in an attempt to address these issues. A cam-based scanner eliminates the motor accelerations/decelerations but not the scanning head vibrations. In this work, we attach a second scanning head to the cam on the opposite side of the first scanning head to counter-balance the mechanical vibrations. With this modification, we improve the limit of detection by more than 3 times (from 69 pM to 20 pM fluorescein). We also increase the capillary number capacity by more than 6 times; the total number of capillaries that can be scanned is 426 if 150-μm-o.d. capillaries are used or 320 if 200-μm-o.d. capillaries are used. To demonstrate the utility of this instrument, we assemble a 99-capillary array on one capillary holder and perform capillary electrophoresis of two fluorescent dyes; separations in all capillaries are successfully monitored simultaneously. We also apply it for detecting fluorescently labeled proteins resolved by 24 s-dimension capillaries in a chip-capillary hybrid device; two-dimensional separation results are nicely produced. [Display omitted] •The cam-based scanner uses two scanning heads to counter-balance the system vibrations.•With this modification the new scanner's limit of detection is reduced by > 3 fold.•The new scanner also increases the number scan-able capillaries by > 6 fold.•The scanner is successfully used for multiplexed CZE and 2-D protein separations.