Electrical detection

Mattauch-Herzog geometry, which simultaneously focuses all resolved masses onto one plane, allowing the integrating properties of an ion-sensitive emulsion to be used as the detector. Although electrical detection with an electron multiplier can be applied, the ion-sensitive emulsion-coated glass photographic plate is the most common method of detection and will be described in this article. 

C. W. Magee. Critical Parameters Affecting Precision and Accuracy in Spark Source Mass Spectrometry with Electrical Detection. PhD thesis, Univetsity of Virginia, University Microfilms, Ann Arbot, MI, 1973. 

Erley G, Gorer S, Penner RM (1998) Transient photocurrent spectroscopy Electrical detection of optical absorption for supported semiconductor nanocrystals in a simple device geometry. Appl Phys Lett 72 2301-2303... 

The development of DNA sensors and high-density DNA arrays has been prompted by the tremendous demands for innovative analytical tools capable of delivering the genetic information in a faster, simpler, and cheaper manner at the sample source, compared to traditional nucleic acid assays. Nanoparticle-biopolymer conjugates offer great potential for DNA diagnostics and can have a profound impact upon bioanalytical chemistry. Nanoparticle/polynucleotide assemblies for advanced electrical detection of DNA sequences have been reviewed by Wang [145]. 

Park S.-J., Taton T.A., Mirkin C.A., Array-based electrical detection of DNA using nanoparticle probes, Science 2002 295 1503-1506. 

T.L. Lasseter, W. Cai, and R.J. Hamers, Frequency-dependent electrical detection of protein binding events. Analyst (Cambridge, United Kingdom) 129, 3-8 (2004). 

Y. Ishige, M. Shimoda, and M. Kamahori, Immobilization of DNA probes onto gold surface and its application to fully electric detection of DNA hybridization using field-effect transistor sensor. Jpn. J. Appl. Phys. 45, 3776-3783 (2006). 

S.Q. Lud, M.G.. Nikolaides, I. Haase, M. Fischer, and A.R. Bausch, Field effect of screened charges electrical detection of peptides and proteins by a thin-film resistor. ChemPhysChem. 7, 379-384 (2006). 

P.A. Neff, A. Naji, C. Ecker, B. Nickel, R. Klitzing, and A.R. Bausch, Electrical detection of self-assembled polyelectrolyte multilayers by a thin film resistor. Macromolecules 39, 463 466 (2006). 

P. Estrela, P. Migliorato, H. Takiguchi, H. Fukushima, and S. Nebashi, Electrical detection of biomolecular interactions with metal-insulator-semiconductor diodes. Biosens. Bioelectron. 20, 1580-1586 (2005). 

SJ. Park, T.A. Taton, and C.A. Mirkin, Array-based electrical detection of DNA with nanoparticle probes. Science 295, 1503—1506 (2002). 

FIGURE 14.5 Multiprotein electrical detection protocol based on different inorganic colloid nanocrystal tracers, (a) Introduction of antibody-modified magnetic beads (b) binding of the antigens to the antibodies on the magnetic beads (c) capture of the nanocrystal-labeled secondary antibodies (d) dissolution of nanocrystals and electrochemical stripping detection (reproduced from [29] with permission). 

Hahm, J.-i. Lieber, C. M. 2004. Direct ultrasensitive electrical detection of DNA and DNA sequence variations using nanowire nanosensors. Nano Lett. 4 51-54. 

In soil analysis, HPLC is used much like GC in that soil is extracted and the extract, after suitable cleanup and concentration, is analyzed. One major difference between them is that HPLC does not require the components to be in the gaseous phase. They must, however, be soluble in an eluent that is compatible with the column and detector being used. A second difference is that both a syringe and an injector are used to move the sample into the eluent and onto the column. Detection is commonly by UV absorption, although RI, conductivity, and mass spectrometry are also commonly used. Conductivity or other electrical detection methods are used when analysis of ionic species in soil is carried out [3,78],... 

J. -M. Spaeth, Magneto-Optical and Electrical Detection of Paramagnetic Resonance in... 

A promising detection principle utilizes similar nebulization procedure as applied in ELS, namely the corona-charged aerosol detectors, CAD. In CAD, the aerosol particles interact with an ionized gas (usually nitrogen). The particles become charged and electrically detected [294]. It has been shown that the response of CAD does not depend on the nature of analyte. On the other hand, the size of the aerosol depends on the mobile phase composition and it has to be calibrated. 

Myers, R. L., and W. L. Fite, Electrical Detection of Airborne Particulates Using Surface Ionization Techniques, Environ. Sci. Technol., 9, 334-336 (1975). 

We further addressed the use of the nucleic acids as biopolymers for the formation of supramolecular structures that enable the electronic or electrochemical detection of DNA. Specifically, we discussed the use of aptamer/low-molecular-weight molecules or aptamer/protein supramolecular complexes for the electrical analysis of the guest substrates in these complexes. Also, nucleic acid-NPs hybrid systems hold a great promise as sensing matrices for the electrical detection of DNA in composite three-dimensional assemblies. While sensitive and selective electrochemical sensors for DNA were fabricated, the integration of these sensor configurations in array formats (DNA chips) for the multiplexed analysis of many DNAs can also be envisaged. 

While our research was concerned with developing wet chemical methods, we confirmed our data with analyses from an available spark source mass spectrometer (SSMS). The SSMS operating parameters are given in Table I. The instrument used was an AEI MS-7 (I, 2) equipped with electrical detection. It was used in the peak switching mode only to provide more precise analyses. 

Instrumentation. The instrument used in this investigation was a commercial Mattauch-Herzog mass spectrometer equipped with photographic and electrical detection systems and an RF spark source. The resolution of the instrument was 1 part in 5,000. All trace elements were determined from mass spectra recorded on Ilford Q-2 photographic... 

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