Real Time Analysis

The essentially non-destmetive nature of Rutherford backscattering spectrometry, combmed with the its ability to provide botli compositional and depth mfomiation, makes it an ideal analysis tool to study thm-film, solid-state reactions. In particular, the non-destmetive nature allows one to perfomi in situ RBS, thereby characterizing both the composition and thickness of fomied layers, without damaging the sample. Since only about two minutes of irradiation is needed to acquire a Rutherford backscattering spectmm, this may be done continuously to provide a real-time analysis of the reaction [6]. 

There are two main applications for such real-time analysis. The first is the detemiination of the chemical reaction kinetics. Wlien the sample temperature is ramped linearly with time, the data of thickness of fomied phase together with ramped temperature allows calculation of the complete reaction kinetics (that is, both the activation energy and tlie pre-exponential factor) from a single sample [6], instead of having to perfomi many different temperature ramps as is the usual case in differential themial analysis [7, 8, 9, 10 and H]. The second application is in detemiining the... 

It is imperative that any HDR reservoir be created in rock which is free of natural faults. This can be accompHshed by a thorough geologic study of a rock body prior to creation of an HDR reservoir within it, by close control of the hydrofracturing operation, and through real-time analysis of microearthquake data arising from joint opening to assure that the HDR reservoir stays within known bounds. 

If further resolution is necessary one-third octave filters can be used but the number of required measurements is most unwieldy. It may be necessary to record the noise onto tape loops for the repeated re-analysis that is necessary. One-third octave filters are commonly used for building acoustics, and narrow-band real-time analysis can be employed. This is the fastest of the methods and is the most suitable for transient noises. Narrow-band analysis uses a VDU to show the graphical results of the fast Fourier transform and can also display octave or one-third octave bar graphs. 

As a consequence, good, safe, steam-sampling points are required, and automatic, real-time continuous analyzer systems for monitoring of steam and condensate quality are very useful. These requirements usually are not a problem in larger power and process HP boiler plants. Here, each facility tends to have a unique combination of operating conditions and waterside chemistry circumstances that necessitate the provision of a steady stream of reliable operational data, and this can be obtained realistically only from continuous, real-time analysis. 

These methods, when combined with real-time analysis of cell response (Omann and Sklar, this volume), also permit a quantitative analysis of the relationship between receptor occupancy and cell response. 

Spectroscopy. A whole variety of speetroscopie methods are available ineluding IR, microwave, Raman and X-ray spectroscopy. In all these cases real-time analysis gives almost instantaneous feedback of results. 

Sensor-based methods. Whilst many methods use sensors, the simplest being temperature measurement, this terminology is often used to cover viscosity, pH, oxygen and humidity determination, etc. These are true in-line techniques and offer rapid, inexpensive real-time analysis. Humidity determination in drying ovens is a common example. 

As the second-generation device contains integrated reaction and detection units, virtually real-time analysis could be achieved (compare to the delay in analysis for the first generation device described above) ]72-74],... 

Real- Time Analysis for Pollution Prevention Analytical methodologies need to be further developed to allow for real-time, in-process monitoring and control prior to the formation of hazardous substances. 

If we were to choose the ideal method for the analysis of any component of seawater, it would naturally be an in situ method. Where such a method is possible, the problems of sampling and sample handling are eliminated and in many cases we can obtain continuous profiles rather than limited number of discrete samples. In the absence of an in situ method, the next most acceptable alternative is analysis on board ship. A real-time analysis not only permits us to choose our next sampling station on the basis of the results of the last station, it also avoids the problem of the storage of samples until the return to a shore laboratory. 

Sakamoto et al. [143] described an automated, near real-time analysis with microprocessor-controlled syringe pump modules for the determination of... 

Information about the state of an interaction can be achieved by a multitude of different readouts. Most of them are based on spectroscopical properties of the biomolecules or the labels introduced and allow real time analysis of the reactions. In some cases samples have to be retained and the analysis has to be performed subsequently. 

Figure 3.1 shows a typical laboratory flow reactor for the study of catalytic kinetics. A gas chromatograph (GC, lower shelf) and a flow meter allow the complete analysis of samples of product gas (analysis time is typically several minutes), and the determination of the molar flow rate of various species out of the reactor (R) contained in a furnace. A mass spectrometer (MS, upper shelf) allows real-time analysis of the product gas sampled just below the catalyst charge and can follow rapid changes in rate. Automated versions of such reactor assemblies are commercially available. 

KEYWORDS laser ablation, LIBS, ICP-MS, real-time analysis, instrumentation... 

Automatization of all stages of the analytical process is a trend that can be discerned in the development of modern analytical methods for chemical manufacture, to various extents depending on reliability and cost-benefit considerations. Among the elements of reliability one counts conformity of the accuracy and precision of the method to the specifications of the manufacturing process, stability of the analytical system and closeness to real-time analysis. The latter is a requirement for feedback into automatic process-control systems. Since the investment in equipment for automatic online analysis may be high, this is frequently replaced by monitoring a property that is easy and inexpensive to measure and correlating that property with the analyte of interest. Such compromise is usually accompanied by a collection of samples that are sent to the analytical laboratory for determination, possibly at a lower cost. 

It is recommended to monitor the performance of the methods during real time analysis in the application labs. Indeed, the best setting for method evaluation is really during actual application to sample batches. In this way, a historical source of objective data is made available that will be the basis for future discussions on method issues between the application and the development labs. 

The data presented in Figs. 3 and 4 are examples of the types of kinetic binding data that are readily acquired with commercially available flow cytometers. Quantitative, real-time analysis of fluorescent A-formyl peptide association with neutrophil receptors has been described by Fay et al. (4), and this publication should be consulted for detailed protocols required for quantitative kinetic assays (see Notes 5 and 6). 

A first approach to determining explosives on-site might include a combination of specialized sample-collection techniques and subsequent analysis using established IMS technologies or instruments. A second level of development could involve the fabrication of analyzers or analytical systems for an on-site operation and real-time analysis of samples. During the past several years, the first step of development has been demonstrated for explosives in water, in soils, and in a few unique uses. 

As a process analytical solution, these extrinsic reactive approaches necessitate an extrinsic optode (see later discussion), an on-line sample conditioning system or an at-Une solution such as a flow injection analysis (FIA) system or other autonomous solutions. Reaction kinetics, post analysis cleanup such as rejuvenating a substrate (optode, immobilized based immunoassays, etc.) among other complexities are additional considerations for these types real-time analysis methods. ... 

Steeghs M, Bais HP, de Gouw J, Goldan P, Kuster W, Northway M, Fall R, Vivanco JM (2004) Proton-transfer-reaction mass spectrometry as a new tool for real time analysis of root-secreted volatile organic compounds in arabidopsis. Plant Physiol 135 47-58... 

O.A. Carmi, A.B. Stewart, S. Ulitzer, and J. Kuhn. 1987. Use of bacterial ludferase to establish a promoter probe vehicle capable of nondestructive real-time analysis of gene expression in Bacillus spp. i, Bacteriol. 169 2165-2170. 

Medina, M. B., VanHouten, L., Cooke, P. H., and Tu, S. I. (1997). Real-time analysis of antibody binding interactions with immobilized E. coli 0157 H7 cells using the BlAcore. Biotechnol. Tech. 11,173-176. 

Gard, E., J. E. Mayer, B. D. Morrical, T. Dienes, D. P. Fergenson, and K. A. Prather, Real-Time Analysis of Individual Atmospheric Aerosol Particles Design and Performance of a Portable ATOFMS, Anal. Chem., 69, 4083-4091 (1997). 

Stoffels, J. J., A Direct-Inlet Mass Spectrometer for Real-Time Analysis of Airborne Particles, Ini. J. Mass Spectrom. Ion Phys., 40, 217-222 (1981a). 

---