Wet Chemistry Techniques

Before the advent of modem instmmental techniques, plastic analysis relied on a sequence of wet chemistry reactions to determine information such as the generic polymer type of a material. 

The amount of wet chemistry carried out in the modem polymer analysis laboratory in the 21st Century is minimal. There are some tests which can still be grouped under this heading, although even some of these can employ an instmmental technique to provide the final answer. 

One such method is the oxygen flask combustion method, which can be used on PVC products to determine the amount of PVC in the formulation by quantifying the chlorine present. 

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Thus, although the analysis of scales and deposits typically is carried out by a combination of wet chemistry techniques and atomic absorption spectroscopy, an identification of the specific nature of the crys-... 

Instead of using high-temperature melting to make the precursor alloys, an alternative wet chemistry technique has been proposed where nickel(O) and aluminum coordination compounds are blended together and treated to give nanocrystalline NiAlx alloys with 1 < x < 3 [48], The alloys are leached in the same way as standard skeletal catalysts. Catalysts with higher activity than commercially available Raney nickel have been prepared by this technique, with the activity attributed to the finer structure and homogeneity of the alloys [48,49],... 

The early Investigations of autoxldatlon were performed on low molecular weight compounds or Involved chemical analysis of the volatile products released from the polymer because the analytical methods consisted of primarily wet chemistry techniques. 

The measurement of non-metal inorganic contaminants, such as cyanide and sulfate, is dependent on wet chemistry techniques, albeit usually automated and with final determination using spectroscopy, ion chromatography or ion-selective electrodes. 

Malley et al. (1993, 1996) also analysed N, P and C content in lake-water seston. The seston was captured on a glass fibre filter, dried and scanned on a NIR reflectance instrnment. A sub-set of the samples was used to develop calibration functions, while the remaining samples were nsed to test the prediction performance. The r -values between NIR predictions of C, N and P, and the wet chemical determinations, ranged between 0.88 and 0.97. The authors concluded that the prediction performance was as good as for the wet-chemistry techniques used. 

Additionally, metals are often used as the catalyst sites for the same reasons as the homogenous catalysts. In the case of heterogeneous catalysts, however, the metals are deposited on the surface of substrates, such as alumina or silica. These metals can be deposited as a fine layer, patterned using wet chemistry techniques, or simply be in the form of nanoparticles, clusters of metal atoms under 100 nm in diameter. 

The general methods for making metal nanoparticles on high surface area of supports are based on wet chemistry techniques, in which the supporting material is mixed with metal precursors in a solution, followed by the deposition of nanoparticle catalysts under a reducing atmosphere [6]. This approach is also used for the large-scale production of catalysts because of its simplicity but often results in nonuniform distribution in size and morphology. New approach to the fabrication of supported metal catalysts becomes desirable in order to develop efficient catalysts. 

The composition of single-phase materials can be determined by a wide range of wet chemistry techniques and bulk analysis procedures, including such varied methods as atomic absorption spectroscopy. X-ray fluorescence, and magnetic resonance spectroscopy. For most materials, however, the chemical composition of each component in a complex microstructure is of interest. In order to ascertain this. 

The nanoplatform production relies on advances in nano-scale production. The production methods are based on relatively simple wet chemistry techniques, as opposed to many complicated physical and chemical nanotechnology schemes. Specific synthetic methods for nanoparticles of different matrices are optimized to produce the nanoplatforms of a specific matrix and loaded with components for a particular application. The batch-to-batch reproducibility of the nanoplatforms is good and the optimized synthetic protocol is reliable to produce the required nanoplatforms. 

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