Mass-sensitive detection

Lange, D., Hagleitner, C., Hierlemann, A., Brand, O., and Baltes, H. (2002). Complementary metal oxide semiconductor cantilever arrays on a single chip Mass-sensitive detection of volatile organic compounds. Anal. Chem. 74,3084-3095. 

Advantages Neutral molecules ionize Less ion suppression Wider dynamic range 103 -104 Mass sensitive detection How 0.5—2.0 mL/min Higher buffer cone, (up to 20 mM)OK Wide range of compounds No problems with thermal stability/volatility Higher MW Concentration sensitive detection Better sensitivity... 

Dickert FL, Lieberzeit P, Gazda-Miarecka S, Halikias K, Mann K-J. Modifying polymers by self-organisation for the mass-sensitive detection of environmental and biogeneous analytes. Sens Actuators B 2004 100 112-116. 

In previous chapters, we have already discussed the mass-sensitive detection of both small molecules and microorganisms and thus have covered the analyte size range below 1 nm and above 10 nm. The gap in between is bridged by macromolecules and some colloidal particles. Special analytical interest is devoted to biomacromolecules, such as proteins and enzymes and nucleic acids, which are also of chnical interest. For these classes of compounds, a wide variety of rapid testing techniques exist, which can also be seen by the mun-ber of excellent and recent reviews both on protein [59] and DNA [60-62] detection. Due to the broad range of techniques already available in chemistry and clinical science, MIP sensor applications for these analytes are still somewhat rare. For entire DNA strands, no imprinting strategy related to... 

As soon as molecular recognition and binding occurs, a shift in the resonance frequency of the crystal is induced. The frequency shift can be easily measured and - as long as the Sauerbrey conditions are fulfilled - interpreted in terms of mass increase. It is the strength of the technique to provide label-free, mass-sensitive detection of the binding reaction at the crystal surface in real time. 

Pasch, FI. and Rode, K., Use of Matrix-assisted Laser Desorption/Ionization Mass Spectrometry for Molar Mass-sensitive Detection in Liquid Chromatography of polymers, /. Chromatogr., 699, 21, 1995. 

Biosensors using atomic force microscopes (AFMs) are devices which employ an atomic force microscope for biological recognition events. The principle of biosensors using atomic force microscopy is mainly based on the mass-sensitive detection of binding events that change the deflection of a cantilever whose surface is modified with immobilized bioreceptors. 

Lange D, Hagleitner C, Hierlemann A, Brand O, Baltes H (2002) Complementary metal oxide semiconductor cantilever arrays on a single chip mass-sensitive detection of volatile oigrmic compounds. Anal Chem 74 3084-3095 Lange U, Roznyatovskaya NV, Mirsky VM (2008) Conducting polymers in chemical sensors and arrays. Anal Chim Acta 614 1-26... 

Pasch H, Rode K. Use of matrix-assisted laser-desorption/ionization mass-spec-trometry for molar mass-sensitive detection in Uquid-chromatography of polymers. J Chromatogr A 1995 699 21-9. 

O. Hayden, R. Bindeus, C. Haderspdck, K.J. Mann, B. Wirl and EL Dicker , Mass-sensitive detection of cells viruses and enzymes with artificial receptors. Sens. Actuators B,91 (1-3) 316-319, 2003. 

Pasch, H., K. Rode, Matrix-assisted laser desorption/ionization MS for molar mass-sensitive detection in LC of polymers, / Chromatogr. A, 1995,699, 21-29. 

Other methods of sensitive detection of radiotracers have been developed more recently. Eourier transform nmr can be used to detect (nuclear spin 1/2), which has an efficiency of detection - 20% greater than that of H. This technique is useful for ascertaining the position and distribution of tritium in the labeled compound (14). Eield-desorption mass spectrometry (fdms) and other mass spectral techniques can be appHed to detection of nanogram quantities of radiolabeled tracers, and are weU suited for determining the specific activity of these compounds (15). 

Chemical Analysis. The presence of siUcones in a sample can be ascertained quaUtatively by burning a small amount of the sample on the tip of a spatula. SiUcones bum with a characteristic sparkly flame and emit a white sooty smoke on combustion. A white ashen residue is often deposited as well. If this residue dissolves and becomes volatile when heated with hydrofluoric acid, it is most likely a siUceous residue (437). Quantitative measurement of total sihcon in a sample is often accompHshed indirectly, by converting the species to siUca or siUcate, followed by deterrnination of the heteropoly blue sihcomolybdate, which absorbs at 800 nm, using atomic spectroscopy or uv spectroscopy (438—443). Pyrolysis gc followed by mass spectroscopic detection of the pyrolysate is a particularly sensitive tool for identifying siUcones (442,443). This technique rehes on the pyrolytic conversion of siUcones to cycHcs, predominantly to [541-05-9] which is readily detected and quantified (eq. 37). 

It is seen that with 1 ml samples the peak for a concentration of 1 ppm is well off scale and a clearly defined peak was observed for 10 ppb. When a 10 ml sample was used, acetophenone at a concentration of 1 ppb could just be detected. Under the conditions used, the ultimate mass sensitivity of the system was about 10 ng. This level of sensitivity was achieved, on the one hand, by the sample concentrating process, and on the other, as a result of the high mass sensitivity of small bore columns. 

The immobilization of the hyperbranched spherical structures onto physical transducers greatly increases the binding capacity of the surface and leads to enhanced sensitivity and extended linearity of biosensors. Nucleic acid dendrimers were prepared and their amplification properties for the detection of DNA were examined using mass-sensitive transducers [45, 46]. Antibodies... 

The choice of the method of analysis depends on the question to address. Spectrophotometry is sufficient for total curcuminoid content determination in a turmeric extract. Separation techniques coupled to mass spectrometry detection and MALDl-TOF are highly sensitive techniques that are more adapted to the identification of metabolites in biological fluids such as urine or plasma. ... 

Column and detector properties determine the minimum amount of a component that can be reliably distinguished from the background noise. If we arbitrarily select a signal to noise ratio of 4 as the minimum value for the confident determination of a peak in a chromatogram then for a mass sensitive detector the minimum detectable amount is given by... 

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