Apparatus, Materials

IE chromatographic systems consist of the same components as any high-performance liquid chromatograph. In many cases, the resins, eluents, and detectors are similar to those used for ion chromatography. Stainless steel HPLC hardware is used except in cases where HCl eluents are used and plastic or glass parts must be used. 

The most commonly used resins are gel type sulfonated cation exchangers or anion exchangers with a quaternary ammonium functional group. The exchange capacity of the resins used is generally higher than those used for ion chromatography. The resins may be either styrene-divinylbenzene copolymeric beads or polyacrylate beads. The diameter of the beads should be small and uniform. Resins with a 5 pm bead diameter are now available. 

A wide variety of columns for lEC is available from Alltech, Dionex, Hamilton, Cetac, Tosoh and others. The column dimensions are often significantly larger (both wider and longer) than IC columns in order to separate substances with only small differences in Ka. 

Acidic eluents are used in separating weak acids (such as carboxylic acids) to repress their ionization and give sharp chromatographic peaks. However, water alone is often a suitable eluent for very weak acids such as carbonic acid and boric acid. 

Organic amines require a basic eluent, such as dilute aqueous sodium hydroxide, to ensure that the amines are in the molecular form and are not ionized. Water alone can be used to elute weak molecular bases. 

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Uniform corrosion is the deterioration of a metal surface that occurs uniformly across the material. It occurs primarily when the surface is in contact with an aqueous environment, which results in a chemical reaction between the metal and the service environment. Since this form of corrosion results in a relatively uniform degradation of apparatus material, it can be accounted for most readily at the time the equipment is designed, either by proper material selection, special coatings or linings, or increased wall thicknesses. 

Mironov (Ref 16) reports that intensive research is going on in the Soviet Union into possible peaceful uses of infrasound in medicine and engineering. Among the projects indicated is the possibility of using directed infrasound to break up polar sea-ice. Should a serviceable apparatus materialize it might also have military applications as an anti-personnel weapon (Ref 17)... 

This is a procedure increasingly used to introduce DNA into cells and various methods are available. I have experience with the calcium phosphate technique which is described below but other techniques are described by Gorman (1985) and Spandidos and Wilkie (1984). For example, Bethesda Research Ltd. supply liposomes which will mediate the uptake of nucleic acids at high efficiency (Feigner and Ringold, 1989) and with practice and the appropriate apparatus material may be injected directly into cells (Ansorge and Pepperkok, 1988). Electroporation is particularly useful for introducing DNA into plant spheroplasts. 

A chemistry kit is a container or box in which are stored some special apparatus/material and so these are readily available for experimentation and demonstration work. 

Maintenance of a proper record of the apparatus, material etc. in the laboratory is one of the important duties of the science master. For this after receipt of articles they should be thoroughly checked and then they be entered in the stock register. 

Materials only slightly hazardous to health. It may be desirable to wear self-contained breathing apparatus. Materials that must be moderately heated before ignition will occur. Water spray may be used to extinguish fire because material can be cooled below its flashpoint. 

The results of a study can be relied on only as far as the study itself is being properly conducted, but also only as far as the circumstances surrounding the study can be ascertained to have been supportive of this reliance. Suitability of apparatus, materials and reagents is thus one of the key points in this judgement. 

Most of the techniques mentioned above can be applied to electrolyte solutions in a straightforward manner. It may be necessary to use different apparatus materials due to the corrosive nature of some electrolyte systems, especially at high temperatures. In addition, special techniques exist to measure activity and osmotic coefficients in electrolyte solutions. These methods are discussed in more detail in reference [70]. 

Workers Apparatus Materials Probe type Measuring system Calibration... 

The highest yields (over 90%) are obtained with a platinxim reaction vessel. Glass may be used as the apparatus material if other material is imavailable, but the product is then quite impure... 

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