Automated capillary electrophoresis with on-line preconcentration by solid phase extraction using a sequential injection manifold and contactless conductivity detection

• Published in: Analytica chimica acta 2012-05, Vol.727, p.1-7
• Main Authors: Mai, Thanh Duc, Bomastyk, Benjamin, Duong, Hong Anh, Pham, Hung Viet, Hauser, Peter C.
• Format: Article
• Language: English
• Subjects: Analysis methods; Analytical chemistry; Applied sciences; Capacitively coupled contactless conductivity detection; Capillary electrophoresis; Chemistry; Chromatographic methods and physical methods associated with chromatography; Drug residues; Electrochemical methods; Exact sciences and technology; General, instrumentation; Natural water pollution; Other chromatographic methods; Pollution; Sequential injection analysis; Solid phase extraction; Water treatment and pollution
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2012.03.035

. [Display omitted] ► Robust preconcentration is possible with a syringe-driven sequential injection based manifold. ► Separation of pharmaceutical compounds was done with capillary electrophoresis. ► Contactless conductivity detection (C4D) was used for narrow capillaries of 25μm. ► Quantification down to the low nanomolar range was achieved. An extension of a capillary electrophoresis instrument coupled to a sequential injection analysis manifold was developed for automated measurements with on-line solid-phase extraction preconcentration. An in-house built capacitively coupled contactless conductivity detector was employed for sensitive detection with narrow capillaries of 25μm internal diameter. The system was assembled into standardized 19in. frames and racks for easy transport and mobile deployment. The system can be left running unattendedly without manual intervention with good operation stability. To demonstrate the application of the system, a method for the determination of four drugs, namely ibuprofen, diclofenac, naproxen and bezafibrate, was developed with enrichment factors of up to several hundreds. Detection of the drug residues down to the nM-scale was found possible and the method was found suitable for the detection of ibuprofen in the waste water of a hospital in Hanoi.