Running costs, availability

The choice of a mass spectrometer to fulfill any particular task must take into account the nature of the substances to be examined, the degree of separation required for mixtures, the types of ion source and inlet systems, and the types of mass analyzer. Once these individual requirements have been defined, it is much easier to discriminate among the numerous commercial instruments that are available. Once suitable mass spectrometers have been identified, it is then often a case of balancing capital and running costs, reUability, ea.se of routine use, after-sales service, and manufacturer reputation. 

There are many techniques available for measuring the particle-size distribution of powders. The wide size range covered, from nanometers to millimeters, cannot be analyzed using a single measurement principle. Added to this are the usual constraints of capital costs versus running costs, speed of operation, degree of skill required, and, most important, the end-use requirement. 

Disadvantages Possible interaction effects on other buried structures (Section 10.6) subject to the availability of a suitable a.c. supply source or other source of d.c. regular electrical maintenance checks and inspection required running costs for electrical supply (usually not very high except in the case of bare marine structures and in power stations where structures are often bare and include bimetallic couples) subject to power shutdowns and failures. 

The system designer must consider these components and examine the options which may be available in order to determine a best selection with reference to first cost, installation, operation, running cost, maintenance and expected life. The following factors are some of those affecting the final decision ... 

Produces strong, blocky coke having good reactivity. Involves low capital and running costs. Production process delinks with availability of markets for byproducts. Allows shut down without any detrimental effects to refractory. Produces hard coke for foundry. The process is characterized by simplicity. There involves no requirements of extra fuel for heating as in by-product oven practice. 

Among the various desulphation systems available in the chlor-alkali industry, the RNDS offers excellent advantages in terms of its low initial and running costs and environmental issues. In addition, it is a simple system and the process design results... 

Steam distillation Low capital running costs Applicable to most essential oils, fragrances and flavour compounds. Designs available to suit all volumes. Unpredictable degradation of some groups of compounds. Cleaning between products can be difficult. Extraction of further products from residue can be difficult due to high moisture level. 

Mass distributions are also determinable using x-ray systems that are available as gravity and centrifugal sedimentometers. These are essential where speed and running costs are more important than capital costs. 

Capillary electrophoresis (CE) is an emerging analytical technique for determination of catechins. The majority of CE studies involve the analysis of catechins in tea infusion, extracts as well as supplements. The three variants of CE suitable for the analysis of catechins include capillary zone electrophoresis (CZE), micellar electro-kinetic chromatography (MEKC), and microemulsion electrokinetic chromatography (MEEKC) with UV detection. In general, the resolution of MEKC was found to be superior to CZE for separation of catechins. MEEKC is a relatively new technique, and the few reports available suggest that it offers a performance similar to MEKC. CE conditions are often quite complex, and many factors, such as buffer composition, pH, presence of surfactants, and column temperature, can all affect the quality of separation and should be optimized individually. On the other hand, CE offers several advantages over HPLC. The short analysis time (<20 minutes), low running costs, and reduced use of solvents make it an attractive alternative for routine analysis of catechins. 

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