Issue 5, 2013

A coupling system of capillary gel electrophoresis with inductively coupled plasma-mass spectrometry for the determination of double stranded DNA fragments

Abstract

The coupling system of capillary gel electrophoresis (CGE) and inductively coupled plasma-mass spectrometry (ICP-MS) was newly developed and successfully applied to the double-stranded (ds) DNA quantification. The developed system combines the separation technique for large biomolecules and element selective detection of ICP-MS. This coupling was achieved by using the modified high performance concentric nebulizer (HPCN) with the PTFE tube (HPCN-PT), which can produce the liquid jet by the flow focusing effect. The HPCN-PT effectively nebulizes the highly viscous solution containing gel buffer even at a low flow rate. At a liquid flow rate of 0.010 mL min−1 and a nebulizer gas flow rate of 1 L min−1, the Sauter mean diameter (D3,2) of primary aerosols generated by the HPCN-PT was 3.4 μm, and over 90% (v/v) of the aerosol droplets were less than 10 μm in diameter. The electrophoresis capillary filled with gel buffer was connected to the HPCN-PT via the interface. This interface has two connectors and an electrode that can connect CE and ICP-MS. After the electrophoretic separation at atmospheric pressure, the samples were transferred to the ICP-MS through the interface by applying additional pressure. Fragments of dsDNA, which were commercially available as a ladder marker solution, were successfully separated and analyzed by measuring 31P+ with CGE-ICP-MS, and a linear calibration curve of the phosphorus standard solution (R2 = 0.999) was obtained from 2.7 to 27 mg kg−1. The detection limit (LOD) and absolute detection limit of P were 3.7 μg kg−1 and 0.6 pg (equivalent to 6 pg of DNA), respectively. This absolute detection limit value was equal to the conventional fluorescence determination of DNA.

Graphical abstract: A coupling system of capillary gel electrophoresis with inductively coupled plasma-mass spectrometry for the determination of double stranded DNA fragments

Article information

Article type
Communication
Submitted
26 Feb 2013
Accepted
10 Apr 2013
First published
10 Apr 2013

Metallomics, 2013,5, 424-428

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