Use of a process colorimeter in industrial processing of tomatoes

A system to provide on-line colour monitoring of tomato products was investigated. The tristimulus colorimeter used can supply hundreds of recordings per second to a remote PC, which elaborates the data in real time and shows the trend of all colorimetric data with respect to any scale. By using the linear regression equation obtained by processing the experimental data it is also possible to predict values for measurements carried out in quality control laboratories during the concentration phase.     

GC analysis of gas in halogen lamps using a new sampling device

Summary A new type of gas sampling device was constructed to improve the analysis of the gas in halogen lamps. Low levels of gases such as O₂, CH₄, C₂H₄ and CH₃Br could be determined by the techniques worked out.     

The process of management review

Management review of the quality-management system is an item in many quality standards and a requirement of the ISO 9001:2000 standard and of laboratory standards ISO 15189 and ISO 17125, and others. These reviews are conducted to ensure that the top management is informed and involved in the quality-management system with respect to continuing adequacy and effectiveness, and opportunities for improvement of the system. The management review is a process that should be conducted and audited utilizing the process approach. A process approach is defined as “An activity using resources and managed in order to enable the transformation of inputs into outputs” (ISO 9001:2000). All identified main processes in the quality system should be monitored through data collection by appropriate methods, assuring that data are valid, representative, and adequate. For management review data must be collected and presented in an accessible form so that processes can be evaluated according to objectives, goals, resources, etc. On the basis of this information the laboratory management makes the necessary decisions and ensure that actions are taken that improve the effectiveness of the quality-management system. As output from the management review process, there should be evidence of decisions regarding: change of quality policy and objectives; plans and possible actions for improvements; corrective actions as appropriate; increased customer satisfaction; and planning of resources needs. Identification of the processes involved and using the process approach in the management review ensures the continual improvement of the quality system. Presented at the conference Quality in the Spotlight, March 2006, Antwerp, Belgium.     

Application of wet chemistry techniques to process analysis and control

The availability of reliable and rugged automatic titrators, flow-injection analysers and ion chromatographs provides opportunities for their application in industrial process analysis. The control of industrial processes such as the removal of sulphur during gas treatment presents a challenge as accurate on-line and in-line analysers are required. The application of automatic titrators and ion chromatographs to the compositional analysis of caustic and alkanolamine gas sweetening solutions is described. Comparisons with other techniques such as flow-injection analysis and ultraviolet and near-infrared spectrometry are made and the pertinent features and benefits of each are discussed.     

Analytical approaches for arsenic determination in air: A critical review

This review describes the different steps involved in the determination of arsenic in air, considering the particulate matter (PM) and the gaseous phase. The review focuses on sampling, sample preparation and instrumental analytical techniques for both total arsenic determination and speciation analysis. The origin, concentration and legislation concerning arsenic in ambient air are also considered. The review intends to describe the procedures for sample collection of total suspended particles (TSP) or particles with a certain diameter expressed in microns (e.g. PM10 and PM2.5), or the collection of the gaseous phase containing gaseous arsenic species. Sample digestion of the collecting media for PM is described, indicating proposed and established procedures that use acids or mixtures of acids aided with different heating procedures. The detection techniques are summarized and compared (ICP-MS, ICP-OES and ET-AAS), as well those techniques capable of direct analysis of the solid sample (PIXE, INAA and XRF). The studies about speciation in PM are also discussed, considering the initial works that employed a cold trap in combination with atomic spectroscopy detectors, or the more recent studies based on chromatography (GC or HPLC) combined with atomic or mass detectors (AFS, ICP-MS and MS). Further trends and challenges about determination of As in air are also addressed.     

Sequential injection: a new concept for chemical sensors,process analysis and laboratory assays

Established flow-injection techniques allow advanced solution handling for laboratory purposes, but chemical sensing and continuous monitoring of chemical processes require dramatically simplified flow schemes and instrumentation with the potential for miniaturization and an inherent ruggedness. Considerations based on the random walk model have led to the concept of sensor injection and sequential injection analysis. This new approach to automated analysis is designed to fill a gap in present flow-injection methodology.     

A way of establishing quality of measurements in gas analysis—national and international aspects

Standardising quality of measurements at both the national and international level results in a unity in measurement that may be regarded a synonym of traceability. In gas analysis, the key issue in achieving this aim is production of gaseous reference materials. Establishing a network of secondary measurement standards at gaseous CRM producers’ sites in Ukraine might be interesting for those involved in gas analysis activities. Inevitably, problems concerning the recognition of measuring capabilities of both national metrological institutes and local CRM producers are now an international issue. Thus, the problems of national adoption of international standards, as well as harmonisation between different international documents are currently relevant, and Ukrainian experience may be useful to others in this field. Presented at the 3rd International Conference on Metrology, November 2006, Tel Aviv, Israel.     

Rapid analysis of hydrocarbons and inert gases by a multidimensional gas chromatograph

A combination of a pressure switching system with multiple columns and photoionization detectors makes possible rapid analysis of a mixture of inorganic gases and hydrocarbons. Hydrocarbons are separated by a narrow bore capillary column. An alumina PLOT column is used for the separation of lower molecular weight hydrocarbons, especially C4 isomers, while a combination of a micro-packed column with Porapak N and a PLOT capillary column with Molecular Sieve 5A is used for the fast separation of inorganic gases. A photoionization detector is a powerful additional tool for organic gas analysis.     

A GC-system for the analysis of residual geothermal gases

Summary The gases evolved from geothermal fields, after condensation of H₂O, CO₂, H₂S and NH₃ in caustic solution, contain He, H₂, Ar, O₂, N₂, CH₄ and higher hydrocarbons. The analysis for the major components in these residual gas mixtures can be achieved by use of two simple gas chromatographs in parallel, and using 5Å molecular sieve. The separation of He and H₂ to baseline is achieved by using low temperatures (30°C) coupled with a relatively long column; and the difficult separation of Ar and O₂ is achieved by use of a cryogenically cooled column. The use of switching valves to backflush and bypass columns ensures that a minimum time for analysis can be achieved whilst retaining baseline separations of the He/H₂ and Ar/O₂ pairs.     

The Process Analytical Technology initiative and multivariate process analysis, monitoring and control

Process analytical technology is an essential step forward in pharmaceutical industry. Real-time analyzers will provide timely data on quality properties. This information combined with process data (temperatures, flow rates, pressure readings) collected in real time can become a powerful tool for this industry, for process understanding, process and quality monitoring, abnormal situation detection and for improving product quality and process reliability. A very important tool for this achievement is the multivariate analysis. Dr. Theodora Kourti is Research Manager in the McMaster Advanced Control Consortium (MACC) and Adjunct Professor in the Chemical Engineering Department at McMaster University. She is the co-recipient of the 2003 University – Industry Synergy Award for Innovation, given by the Natural Science & Engineering Research Council of Canada. Dr. Kourti has been working on Multivariate Statistical Methods for Process and Product Improvement and Abnormal Situation Detection in Process Industries since 1992 and has been involved in more than 80 major industrial applications in North America and Europe. These are either off-line or real-time applications for batch and continuous processes, in diverse industries such as Chemicals, Pharmaceuticals, Semiconductor, Mining, Pulp and Paper, Petrochemicals, Photographic and Steel Industry. She has published extensively in this area and has provided training for numerous industrial practitioners.     

Time-series analysis in analytical process control

Analysis of time series tries to extract tendencies from measured values dependent on time. For this purpose the cusum technique has proved to be a very sensitive tool for the evaluation of both current and completed time series. Even very weak tendencies can be detected at a high level of noise. Time-series analysis further tries to predict values to come from hitherto performed measurements. As a very flexible model exponential smoothing could be successfully used. Even for processes with a high extent of non-stationarity this model allowed a good prediction owing to the dynamics of the process. Three types of time-series analysis, i.e., evaluation of current measurements, retrospective evaluation and prediction of data (also known as “in vivo”, “post mortem” and “in futurum” time-series analysis) are demonstrated for problems stemming from analytical process control.     

A review of very large scale chromatography

Summary The relative merits of large scale gas chromatography (GC) and high performance liquid chromatography (HPLC) have not been reviewed for some considerable time. Although methodologies capable of manufacturing high efficiency (and hence cost effective) plant have existed for over a decade, commercial introduction has been remarkably slow. This has primarily been caused by confidentiality restrictions placed on equipment manufacturers, in turn severely limiting wide ranging applications data. These are necessary to raise potential end users confidence that both techniques offer viable large scale routes to separation and purification of mixtures as analysed by laboratory chromatographic methods. Considerable recent progress has been made with large scale HPLC plant, which has led to sufficient published data to make both technical and economic comparisons against GC possible.     

Passive sampling and/or extraction techniques in environmental analysis: a review

The current state-of-the-art of passive sampling and/or extraction methods for long-term monitoring of pollutants in different environmental compartments is discussed in this review. Passive dosimeters that have been successfully used to monitor organic and inorganic contaminants in air, water, sediments, and soil are presented. The application of new approaches to the determination of pollutants at the sampling stage is discussed. The main milestones in the development of passive techniques for sampling and/or extraction of analytes, and in biomonitors used in environmental analysis, are summarized in this review. Passive samplers and biomonitors are compared.     

Analytical theory for permeation of condensable gases in a nanopore

The permeation of a condensable gas mixture in a pressure gradient is examined within a dynamic density functional theory (DDFT). The non-equilibrium density and flux profiles of gas molecules trapped within a nanopore are calculated for each species as a function of feed gas density. Because of important fluid–fluid interaction close to condensation the flux and density gradients are not related by constant transport diffusivities with the thermodynamic correction of uniform density. For long narrow pores the relation of the selectivity to the equilibrium adsorption isotherms is validated. Improved separation is achieved by combining preferential wall interaction and advantageous attraction between gas molecules of different species and examples are discussed. Results from experiments and simulations of permeation in binary mixtures near condensation are still rare and the theory provides a simple basis to study qualitative trends using known parameters.     

The use of the electron capture detector in human and equine doping analysis by gas chromatography

Summary The possibilities, applications and limitations of the electron capture detector (ECD) in human and equine doping analysis are considered. As many stimulants and/or their metabolites possess and amino group the introduction of halogen containing groupings by acylation results in improved chromatographic performance almost combined with enhanced sensitivity and selectivity when using the ECD. Several examples of the confirmation of doping agents like amphetamines, ephedrine, phenylbutazone, pemoline and procaine by GC/ECD are given.Presented at the 7^th International Symposium on Biomedical Applications of Chromatography, Hradec Králové, Czechoslovakia; 6–9 Sept. 1982.     

Considerations of comparability and traceability for food analysts

Presented at the CCQM Workshop on Comparability and Traceability in Food Analysis (18–19 November 2003, BIPM, Sevres, France), consideration is given to the interpretation of comparability and traceability to food analysis. The difficulties and complexities of food analysis are discussed and a case is made for how the principles of comparability and traceability may be used to ensure high levels of analytical quality.Presented at the CCQM Workshop on Comparability and Traceability in Food Analysis, 18–19 November 2003, BIPM, Sèvres, France.     

Towards quantitative laser-induced breakdown spectroscopy analysis of soil samples

A quantitative analysis of chromium in soil samples is presented. Different emission lines related to chromium are studied in order to select the best one for quantitative features. Important matrix effects are demonstrated from one soil to the other, preventing any prediction of concentration in different soils on the basis of a univariate calibration curve. Finally, a classification of the LIBS data based on a series of Principal Component Analyses (PCA) is applied to a reduced dataset of selected spectral lines related to the major chemical elements in the soils. LIBS data of heterogeneous soils appear to be widely dispersed, which leads to a reconsideration of the sampling step in the analysis process.     

On practical metrology and chemical analysis: legal,institutional and technical evolutions in the Australian national measurement system

 Economic and technological change, regional and international trade and the globalisation of industry have led to intense pressures for improvements to analytical quality, reliability and comparability. Of central importance are national traceability structures connecting chemical measurements in the field with internationally accepted measurement units and their practical realisations. Australia has a developed physical and engineering measurement system, a legislative framework for analytical traceability and, in the National Association of Testing Authorities, a recognised laboratory accreditation system. The need has been identified to develop the technical capability to perform matrix-independent reference measurements for the certification of traceable reference materials, useable as practical analytical etalons to establish metrological control systems in field measurements for amounts of substance. Recently, a unique collaborative consortium has proposed a National Analytical Reference Laboratory (NARL). The NARL is designed to be a metrological mass spectrometry facility for the transference of measurement units to more widely useable chemical measurement standards and reference materials. Received: 10 October 1995 Accepted: 26 October 1995     

Gas chromatographic analysis of methyldemeton

Summary A gas chromatographic method is described for the analysis of methyldemeton present in the form of two isomers,O,O-dimethyl O-2-(ethylthio)ethylphosphorothioate andO,O-dimethyl S-2(ethylthio)ethylphosphorothioate in mixtures containg benzene, xylene, 3-thiapentanol-1, andO,O,O-trimethylthiophosphate. Such mixtures are obtained when methyldemeton is synthesized fromO,O-dimethylchlorothiophosphate and 3-thiapentanol-1 [1]. The best results are obtained using a short stainless steel column packed with 5% (w/w) OV-17 on Chromosorb G AW-DMCS 100–120 mesh.     

Solid-state gas sensors for breath analysis: A review

The analysis of volatile compounds is an efficient method to appraise information about the chemical composition of liquids and solids. This principle is applied to several practical applications, such as food analysis where many important features (e.g. freshness) can be directly inferred from the analysis of volatile compounds.