PMID- 34212593 OWN - NLM STAT- PubMed-not-MEDLINE DCOM- 20210702 LR - 20220915 IS - 1872-2059 (Electronic) IS - 1000-8713 (Print) IS - 1000-8713 (Linking) VI - 39 IP - 8 DP - 2021 Aug TI - [Multimaterial 3D-printed contactless conductivity/laser-induced fluorescence dual-detection cell for capillary electrophoresis]. PG - 921-926 LID - 10.3724/SP.J.1123.2021.02021 [doi] AB - Dual detection, which simultaneously employs two complementary detection methods, is a useful approach to enhance the selectivity and sensitivity of capillary electrophoresis (CE). Through dual detection, multiple classes of analytes with different structural and chemical characteristics can be sensitively detected using a single CE method. In addition, the comigrating peaks can be distinguished by comparing the signal outputs of two detectors with different selectivities. Typically, dual detection is achieved by coupling two detectors in series along a capillary. However, in this approach, it is inconvenient to evaluate the signal outputs of the two detectors. The two detectors present differences in their corresponding effective capillary lengths and dead volumes of the detection cell. Therefore, detectors that combine two or three detection methods in a single detection point are proposed to address this issue. In this work, to fabricate a combined detector in a simple and low-cost manner, multimaterial 3D printing technology is employed. A two-in-one detection cell that combines capacitively coupled contactless conductivity detection (C(4)D) and confocal laser-induced fluorescence (LIF) detection was fabricated by 3D printing functional materials. In 3D printing, conductive composite polylactic acid (PLA, Proto-pasta) filaments and normal nonconductive PLA filaments were employed. The conductive material was used to build a C(4)D shielding layer that was electrically grounded. The nonconductive PLA was used as an electrical insulator placed between the shielding layer and C(4)D electrodes, which were two stainless-steel tubes (0.4 mm i.d. and 5 mm length). To embed the electrodes into the nonconductive material, a "print-pause-print" approach was applied. After building two chambers for housing electrodes using nonconductive PLA, the 3D printing was paused, following which the two electrodes were manually installed. Printing was then resumed, and the remaining part was built. The two electrodes were 2 mm apart, and the gap between them was filled with a conductive material for shielding to eliminate stray capacitance. A through-hole (1 mm i.d.) was placed between the middle conductive shielding layer for LIF detection. The size of the detection cell was 60 mmx29 mmx7.2 mm. The cell was screwed onto an XYZ stage to precisely align the light path of LIF detection, which was realized using a TriSep (TM)-2100LIF detector equipped with a 473 nm laser. C(4)D detection was achieved using a TraceDec detector equipped with a ChipCE adaptor. The two-in-one detector was coupled with a lab-made CE system that had a flow-through injection interface. Use of the detection cell allows the simultaneous detection of inorganic cations and fluorescein isothiocyanate (FITC)-labeled amino acids. The C(4)D excitation frequency and buffer concentration were then optimized. A mixture of 10 mmol/L 3-(N-morpholino)propanesulfonic acid (MOPS) and 10 mmol/L bis(2-hydroxyethyl)amino-tris(hydroxymethyl)methane (Bis-Tris) was selected as the background electrolyte as a compromise of C(4)D signal-to-noise ratio (S/N) and separation efficiencies of amino acids. The C(4)D excitation frequency was set to 77 kHz with S/N=233+/-8 for 200 mumol/L Na (+). The baseline separation of Na(+), K(+), Li(+), FITC, fluorescein, histidine (His), lysine (Lys), tryptophan (Trp), phenylalanine (Phe), alanine (Ala), and glycine (Gly) was achieved with a 25 mum i.d.x365 mum o.d.x45 cm (35 cm effective length) capillary and -10 kV separation voltage. The limits of detection (LODs) of C (4)D for Na(+), K(+), and Li(+)were 2.2, 2.0, and 2.6 mumol/L, respectively. The LODs of LIF for fluorescein and FITC were 7.6 and 1.7 nmol/L, respectively. The relative standard deviations (RSDs) of the two detection methods were within the range of 0.3%-4.5% (n=3). The r (2) of the calibration curves was >/=0.9904. Thus, 3D printing technology is a simple and low-cost approach to implement complex designs, including those that are difficult to fabricate by traditional "workshop" technologies. FAU - Zhang, Piwang AU - Zhang P AD - School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin 541004, China. FAU - Yang, Liye AU - Yang L AD - School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin 541004, China. FAU - Liu, Qiang AU - Liu Q AD - School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin 541004, China. FAU - Lu, Shangui AU - Lu S AD - Pinchuang Testing (Guangxi) Corporation, Guilin 541004, China. FAU - Liang, Ying AU - Liang Y AD - School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin 541004, China. FAU - Zhang, Min AU - Zhang M AD - School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin 541004, China. LA - chi PT - English Abstract PT - Journal Article PL - China TA - Se Pu JT - Se pu = Chinese journal of chromatography JID - 9424804 SB - IM PMC - PMC9404044 OTO - NOTNLM OT - capacitively coupled contactless conductivity detection (C4D) OT - capillary electrophoresis (CE) OT - dual detection OT - laser induced fluorescence (LIF) OT - on-capillary detection EDAT- 2021/07/03 06:00 MHDA- 2021/07/03 06:01 PMCR- 2021/08/08 CRDT- 2021/07/02 07:08 PHST- 2021/07/02 07:08 [entrez] PHST- 2021/07/03 06:00 [pubmed] PHST- 2021/07/03 06:01 [medline] PHST- 2021/08/08 00:00 [pmc-release] AID - 1000-8713-39-8-921 [pii] AID - 10.3724/SP.J.1123.2021.02021 [doi] PST - ppublish SO - Se Pu. 2021 Aug;39(8):921-926. doi: 10.3724/SP.J.1123.2021.02021.