Instrumentation common terms

STM and SFM belong to an expanding family of instruments commonly termed Scanning Probe Microscopes (SPMs). Other common members include the magnetic force microscope, the scanning capacitance microscope, and the scanning acoustic microscope. ... 

Silent-hours operation, which is commonly termed hands-off analysis, requires the automatic analysis to operate to a set protocol. For a fully automatic instrument to run in this manner, it will require a feedback system comparing the results with check cahbration standards. A calibration graph can be constructed from the analytical data, and the precision of this graph is easily evaluated. As the analyses proceed, the system can be monitored by reference to the check calibration standards. Should the performance remain within specification, the analyses can safely go on. The automatic instrument can then operate within the set protocols throughout the silent hours, taking full account of any variations in the instrument and its operating parameters. 

There is a wide variety of important static terms and properties related to instrumentation which require careful definition and understanding. Some of these are frequently used in a misleading or even incorrect context. Expressions such as the accuracy of an instrument or its precision or its sensitivity are often employed by manufacturers in a casual or imprecise manner. A brief description of the more common terms follows. 

Common tandem-in-space instruments employ a quadrupole as the first mass analyzer, a multipole collision cell (usually hexapole) operated in RF-only mode, and then either a second quadrupole or a TOF tube as the second mass analyzer. These instruments are termed triple or tandem quadrupole and quadrupole-time-of-flight mass spectrometers. 

Bonds are debt instruments that represent cash flows payable during a specified time period. They are essentially loans. The cash flows they represent are the interest payments on the loan and the loan redemption. Unlike commercial bank loans, however, bonds are tradable in a secondary market. Bonds are commonly referred to 3S fixed-income instruments. This term goes back to a time when bonds paid fixed coupons each year. That is... 

A list of common terms and definitions that are used with respect to instrument qualification, cahbration and maintenance is provided below. More details are provided in cited sections or later in this section. 

The increasing interest in NMR spectroscopy of what in some conferences in this field is commonly termed "other nuclei" is unmistakable. Chemists and biologists who employ NMR spectroscopy to study their problems have, however, been somewhat reluctant to study nuclei with electric quadrupole moments. These nuclei frequently give rise to broad NMR signals, sometimes too broad to be detectable with ordinary high resolution NMR spectrometers. Spectrometers that could cope with broad NMR signals of low intensity, "wide-line" spectrometers, have been available since the mid 1950 s but it appears that most of these instruments ended up in physical laboratories where the research was primarily directed towards solid state problems. 

Safety instrumented system (SIS) SIS is meant to prevent, control, or mitigate hazardous events and take the process to a safe state when predetermined conditions are violated. An SIS can be one or more SIFs, which is composed of a combination of sensors, logic solvers, and final elements. Other common terms for SISs are safety interlock systems, emergency shutdown (ESD) systems, and safety shutdown systems (SSDs). So, SIS is used as a protection layer between the hazards of the process and the public. SIS or SIF is extremely important when there is no other non-instrumented way of adequately eliminating or mitigating process risks. As per recommendations of standards lEC 61511 2003 (or ANSI/ ISA-84.00.01-2004), a multi-disciplinary team approach following the safety life cycle, conducts hazard analysis, develops layers of protections, and implements an SIS when hazardous events cannot be controlled, prevented, or mitigated adequately by non-instrumented means. 

Improvements in all practical aspects of TLC process culminated in a performance breakthrough resulting in an increase in separation efficiency, sample detectability limits, and reduced analysis time the specific advance in instrumentation was termed as HPTLC. Chapters 5 and 7 in this volume describe basic and theoretical aspects of application of instrumentation in TLC, and OPLC. That HPTLC could be used with advantage for the separation of PTH-amino acids was recognized by Bucher (1 SOm) and Yang (150n). But they could not achieve separation of all 20 common PTH-amino acids. Schuette and... 

The technique of internal normalization is commonly apphed in both MC-ICP-MS and TIMS for the precise correction of the instrumental mass bias (see also Chapter 5) that is encountered during the analysis of radiogenic isotopic compositions [33, 34]. The ICP ion source of MC-ICP-MS, however, also features two characteristics that play an important role for isotopic analysis, where internal normalization cannot be applied. First, an ICP source operates at steady state and therefore mass fractionation is not primarily a time-dependent process, as in TIMS where the measured isotopic compositions change with time due to the progressive evaporation of a sample from the filament. The steady-state operation of an ICP ion source is beneficial for the correction of instrumental mass bias by external standardization, where the isotope ratio data obtained for a sample are referenced to the values obtained for bracketing analyses of an isotopic standard [27, 35]. Hence, this procedure is commonly termed standard-sample bracketing. 

Although the power spectral density contains information about the surface roughness, it is often convenient to describe the surface roughness in terms of a single number or quantity. The most commonly used surface-finish parameter is the root-mean-squared (rms) roughness a. The rms roughness is given in terms of the instrument s band width and modulation transfer function, M(p, q) as... 

Flammable atmospheres can be assessed using portable gas chromatographs or, for selected compounds, by colour indicator tubes. More commonly, use is made of explos-imeters fitted with Pellistors (e.g. platinum wire encased in beads of refractory material). The beads are arranged in a Wheatstone bridge circuit. The flammable gas is oxidized on the heated catalytic element, causing the electrical resistance to alter relative to the reference. Instruments are calibrated for specific compounds in terms of 0—100% of their lower flammable limit. Recalibration or application of correction factors is required for different gases. Points to consider are listed in Table 9.10. 

Table 10.32 is a shortlist of the characteristics of the ideal polymer/additive analysis technique. It is hoped that the ideal method of the future will be a reliable, cost-effective, qualitative and quantitative, in-polymer additive analysis technique. It may be useful to briefly compare the two general approaches to additive analysis, namely conventional and in-polymer methods. The classical methods range from inexpensive to expensive in terms of equipment they are well established and subject to continuous evolution and their strengths and deficiencies are well documented. We stressed the hyphenated methods for qualitative analysis and the dissolution methods for quantitative analysis. Lattimer and Harris [130] concluded in 1989 that there was no clear advantage for direct analysis (of rubbers) over extract analysis. Despite many instrumental advances in the last decade, this conclusion still largely holds true today. Direct analysis is experimentally somewhat faster and easier, but tends to require greater interpretative difficulties. Direct analysis avoids such common extraction difficulties as ... 

Damping is often expressed in terms of quantities conveniently obtained with the type of instrument used. Since there are so many kinds of instruments, there are many damping terms in common use, such as the logarithmic decrement A, the half-width of a resonance peak, the half-power width of a resonance peak, the Q factor, specific damping capacity i <, the resilience R, and decibels of damping dB. 

Numerous other FOCS schemes have been described for heavy metals in the past 20 years (for reviews, see 113-115). In looking at the more recent literature one may state, however, that some of the newly described "chemistries" perform hardly better than the rather old commercial systems based on the use of dry reagent chemistries, with the additional advantage that they are compatible with a single instrument for read-out. In fact, some of the newer systems involve rather extensive chemistry and - worst of all -seem to strongly differ in terms of spectroscopy and analytical wavelengths so that they all require their own opto-electronic platform. On the other hand, there is substantial need for (low-cost) sensors for less common... 

Once into the 21st century, hyphenated instrumentation (i.e., those that couple two instruments together) became prevalent in laboratories. This is the combination of two or more, often different, instruments. In simple terms, the purpose is to first separate the analyte of interest and then to identify it. This takes place using a sample injected into the combined instruments. The most common of the hyphenated instruments is the gas chromatograph, the output of which is fed into a mass spectrometer to produce a gas chromatography-mass spectrometry (GC-MS) [35],... 

The basic components of an LC-NMR system are some form of chromatographic instrument and an NMR spectrometer equipped with a flow-probe, as shown in Fig. 19.17. In terms of the chromatography of choice, there are many examples in the literature of a wide array of separation instruments employed, from SFC to capillary electrophoresis (CE) [87,88]. By far the most common method (not necessarily the best choice from a separation point of view) of achieving the desired separation is through HPLC. There are many commercial... 

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