Commercially available instruments

The Corning Ion-meter 135 and the Orion 811 are representative examples of pH-meters with and without a built-in microprocessor, respectively. The latter shows the cell voltage at equilibrium. Its temperature sensor automatically corrects the error due to the difference in temperature between the standards and the sample. When the potential difference between two standards varies significantly from the theoretical expectation, the Instrument shows the deviation. The microprocessor of the Ion-meter 135 allows the automatic use of different measurement programs (e.g. standard additions, sample addition, pH determination). Data can be stored In the memory for subsequent calculations. The microprocessor can also be used Independently. 

To follow the trend of the automation of the potentlometrlc technique, various manufacturers have launched a series of single- and multi-parameter analysers for the determination of gases and liquids, which are discussed below. 

The Radiometer ICA 113 Is an Improved version of their former ICA 1. It Is a modular Instrument for the automatic anaerobic measurement of calcium and pH in serum and plasma. Because of the close relationship between these two parameters, their simultaneous measurement Is essential as a normal Ionized calcium value may be accompanied by an anomalous pH and vice versa —this may lead to erroneous diagnoses. The sensor of the ICA 113 consists of an F2111 Ca Selec-trode whose PVC membrane Is protected from contamination by proteins by a 

The automated ISE-based (glass and valinomycin) instruments commercially available for the determination of sodium and potassium compete advantageously with flame photometers for the same purpose. Representative examples of this type of potentlometrlc Instrument are the KNAI sodium-potassium analyser from Radiometer, the Electrolyte II (In semi- and fully automatic versions) from Beckman and the Nova 1 from Biomedical Laboratories. 

The relevance to clinical chemistry of Instruments capable of determining gases or performing acid-base equilibrations on blood Is obvious. Manufacturers have marketed various blood gas analysers for the determination of crucial parameters In human serum. 

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Fokker Bond Tester. An ultrasonic inspection technique commonly used for aircraft structures is based on ultrasonic spectroscopy [2]. Commercially available instruments (bond testers) used for this test operate on the principle of mechanical resonance in a multi-layer structure. A piezoelectric probe shown in Figure 3b, excited by a variable frequency sine signal is placed on the surface of the inspected structure. A frequency spectrum in the range of some tens of kHz to several MHz is acquired by the instrument, see Figure 3a. 

Figure 3.15 The Rheovibron Viscoelastometer, a commercially available instrument for the determination of the dynamic moduli and compliances. [Photo courtesy of Imass, Inc, Accord (Hingham), Mass. 02018.]...

Figure 12.14 IR spectra of (a) hexane, (b) Vhexene, and (c) 1-hexyne. Spectra like these are easily obtained on milligram amounts of material in a few minutes using commercially available instruments.

The sensitivity of the fluorescence methods varies considerably with the instrument used. Advances in modern instrumentation and the power of today s computers allow for a much improved sensitivity. Using commercially available instruments and modern computers equipped with appropriate software, detection limits down to 10 pg of calf thymus DNA can be achieved using ethidium bromide. (We have achieved such levels using several Perkin-Elmer MPF66 Instruments at various locations.)... 

We are first concentrating on commercially-available instrument technologies providing in situ measurements in polymer reactors, as opposed to those requiring new instrument development or external sampling loops. 

However, these analogues are actually hypothetical. The reason for this is that it is nearly impossible to obtain optical measurement components, such as the source and the detector, whose response to light across the visible spectrum is flat (or nearly so). However, this is not an impossible task and we find that an excellent match can be obtained to the transmission functions of 7.8.21., i.e.-those of the Standard Observer. This is typical for commercially available instruments. Now, we have an instrument, called a Colorimeter, capable of measuring reflective color. 

We find that an excellent match can be obtained to the transmission functions of 7.8.20. This is typical for commercially available instruments. Now, we have ein instrument, called a Colorimeter, capable of measuring reflective color. 

Supercritical fluid chromatography (SEC) was first reported in 1962, and applications of the technique rapidly increased following the introduction of commercially available instrumentation in the early 1980s due to the ability to determine thermally labile compounds using detection systems more commonly employed with GC. However, few applications of SEC have been published with regard to the determination of triazines. Recently, a chemiluminescence nitrogen detector was used with packed-column SEC and a methanol-modified CO2 mobile phase for the determination of atrazine, simazine, and propazine. Pressure and mobile phase gradients were used to demonstrate the efficacy of fhe fechnique. 

The use of SCF as extracting media and mobile phases for chromatography is now commonplace, and SFE and SFC occupy established niches in analytical chemistry. Commercially available instrumentation for SFE and SFC have been available since the mid 1980s. Basic requirements for analytical scale SFE equipment that can perform selective removal or solubilisation of target analytes or analyte classes consist of a... 

In a different approach a super-high-throughput ee-assay was developed on the basis of chirally modified capillary array electrophoresis (CAE).90 CAE was used in the Human Genome Project, and commercially available instruments have been developed which comprise a high number of capillaries in parallel, for example the 96-capillary unit MegaBACE consisting of 6 bundles of 16 capillaries.91 The system can address a 96-well microtiter plate. It was adapted to perform ee-determinations of chiral amines, which are potentially accessible by catalytic reductive amination of ketones, transition metal catalyzed Markovnikov addition of ammonia, or enzymatic hydrolysis of acetamides (Scheme 14).90... 

Figure 1 Comparison of the prices of commercially available instruments used for element analysis...

Commercially available instruments include the SEsitive Detector of Exothermic processes (SEDEX) [103,104], SIKAREX [106], with a typical sensitivity of 0.5 W/kg), and RADEX [102, 108]. This equipment can also be run inisothermal and scanning modes. 

Quadmpole analyzers have generally been considered to give poor mass accuracy. Recently, however, with better machined parts and better electronics, commercially available instruments can perform quite well. A mass accuracy <5 ppm can be obtained with internal calibrants. 

Some commercially available instruments, in addition to visible spectrophotometers, can also perform measurements in the UV and near IR regions of the spectrum. 

The different types of thermobalances which are used today in research laboratories and in industry are usually bound to and designed for specific applications. They may either be commercially available instruments, or assembled from individual components or completely homemade6,7 13 1S. As an example, the set-up of a modern thermobalance is shown schematically in Fig. 5. This type of instrument with its... 

It should be noted that most commercially available instruments are delivered with a file containing the correction factors. 

Temperature measurements. It is well-known that several generally commercially available instruments, based on different principles, may be used for temperature measurement and control. We will take a look at a few types, but a little more attention will be devoted to the thermocouple devices. 

Commercially available instrumentation for absorbance and fluorescence measurements in the NIR region is scarce. Conventional absorbance spectrophotometers... 

At the present time, two methods are in common use for the determination of time-resolved anisotropy parameters—the single-photon counting or pulse method 55-56 and the frequency-domain or phase fluorometric methods. 57 59) These are described elsewhere in this series. Recently, both of these techniques have undergone considerable development, and there are a number of commercially available instruments which include analysis software. The question of which technique would be better for the study of membranes is therefore difficult to answer. Certainly, however, the multifrequency phase instruments are now fully comparable with the time-domain instruments, a situation which was not the case only a few years ago. Time-resolved measurements are generally rather more difficult to perform and may take considerably longer than the steady-state anisotropy measurements, and this should be borne in mind when samples are unstable or if information of kinetics is required. It is therefore important to evaluate the need to take such measurements in studies of membranes. Steady-state instruments are of course much less expensive, and considerable information can be extracted, although polarization optics are not usually supplied as standard. 

Fortunately, the detector performance is in the same order for commercially available instruments. Still a re-validation of the DL is recommended for methods that investigate trace impurities. A significant change of precision data by a different S/N ratio would be found during the repeatability test. 

We will first review the principles of indirect detection, how it works, and what are its requirements. Thereafter, we will focus on considerations concerning buffer composition and sample preparation. The goal is to develop tools that can be used today with commercially available instruments present in many pharmaceutical companies. We will also review available publications and, in an addendum, describe a complete assay for phosphate as a counterion and an impurity. 

Methods of measuring the components of photochemical smog are reviewed in Chapter 6. There have been significant advances in the calibration of instruments for monitoring ozone in ambient air. A method based on the absorption of ultraviolet radiation at 254 nm has been adopted by California for the calibration of air monitoring instruments. The method is based on the use of a commercially available instrument that measures ultraviolet absorption as a transfer standard in the calibration process. 

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