title: 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 (31)P(+) with CGE-ICP-MS, and a linear calibration curve of the phosphorus standard solution (R(2) = 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.
authors.affiliation: National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan. s-fujii@aist.go.jp
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Fujii
authors.forename: Kazumi
authors.initials: K
authors.lastname: Inagaki
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Miyashita
authors.forename: Keisuke
authors.initials: K
authors.lastname: Nagasawa
authors.forename: Koichi
authors.initials: K
authors.lastname: Chiba
authors.forename: Akiko
authors.initials: A
authors.lastname: Takatsu
mesh_terms: D004247:DNA / Q000032:analysis*; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D009330:Nebulizers and Vaporizers; D010758:Phosphorus / Q000032:analysis; D011138:Polytetrafluoroethylene; D013054:Spectrophotometry, Atomic / Q000295:instrumentation / Q000379:methods*
chemical_list: D010758:Phosphorus; D011138:Polytetrafluoroethylene; D004247:DNA