Micro-chemical analytical techniques

The A-ratio provides some indication of precipitate composition, but additional information from micro-chemical analytical techniques is required to determine absolute precipitate size distributions. 

Lu H, Schmidt MA, Jensen KF (2001) Photochemical Reactions and On-Line UV Detection in Microfabricated Reactors. Lab Chip 1 22-28 Manz A, Harrison DJ, Verpoorte EMJ, Fettinger JC, Ludi H, Widmer HM (1991) Miniaturization of Chemical-Analysis Systems - A Look into next Century Technology or just a Fashionable Craze. Chimia 45 103-105 McCreedy T (1999) Reducing the Risks of Synthesis. Chem Ind 15 588-590 McCreedy T (2000) Fabrication Techniques and Materials Commonly Used for the Production of Microreactors and Micro Total Analytical Systems. Trac Trends Anal Chem 19 396-401... 

IUPAC Analytical Chemistry Division, Commission on Micro-chemical Techniques and Trace Analysis, Pure Appl. Chem., 49 (1977) 893. 

Preparation of purified samples for alpha-particle spectrometry is usually by either electrodeposition or micro-coprecipitation. Either technique takes at least an hour. Many beta-particle emitters are precipitated with several milligrams of carrier and weighted for determining the chemical yield prior to counting, which also takes time. In contrast, a few millilitres of solution are satisfactory for ICP-MS. If the analyte concentration should exceed the linear part of the calibration curve, a simple dilution overcomes the problem. 

The mass spectrometer is now widely accepted as a crucial analytical tool for organic molecules in the pharmaceutical industry. Although usually treated as a spectroscopic technique, it does not rely on the interaction with electromagnetic radiation (light, infrared, etc.) for the analysis. Rather it is a micro-chemical technique relying on the production of characteristic ions in the gas phase, followed by the separation and acquisition of those ions. By its operation, it destroys the sample unlike other techniques, such as nuclear magnetic resonance (NMR), infrared (IR) and Raman/UV spectroscopies. Nonetheless, mass spectrometry is so sensitive that molecular weight and structural information can be provided on very small samples (attomolar (10" molar) quantities). 

Advanced analytical methods enable an in-depth study of chemical and morphological characteristics of micro- and nanografted polymer materials. Often, the combination of several techniques is necessary to obtain a detailed picture. Investigations of simplified model systems such as nonstructured grafted surfaces, brushes produced on nonpoly-meric substrates, or selectively derivatized or stained samples are needed for comparison or as standards. Furthermore, the adaptation of biochemical and chemical assay techniques is useful to complete the picture of the produced structures and their functionalities. 

The micro-TA instrument is a prime example of the fact that, in addition to providing a wealth of data on the chemical structure, morphology and chemical properties of a polymer sample, the ability of these techniques to be combined with each other and other analytical techniques (e.g. IR, GC and MS) enables their capability to be enhanced significantly. 

One of the new trends in chemical analysis appeared in the last decade is that the miniaturization. It becomes apparent in the miniaturization of analytical devices, separation procedures, measuring tools, analyzing samples and as a consequent the term micro have appeared. Further development of this trend have led to transfer from the term micro to nano one (nanoparticles, nanofluides, nanoprobes, nanoelectrodes, nanotubes, nanoscale, nanobarcode, nanoelectrospray, nanoreactors, etc). Thereupon a nanoscale films produced by Langmuir-Blodgett (LB) technique are proposed for modifying of chemical sensors. 

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