On-line Analytical Techniques Research Articles

A quantitative on-line analysis of salt in cured ham by near-infrared spectroscopy and chemometrics

In this work, non-invasive near-infrared spectroscopy (NIRS) combined with chemometrics was evaluated as a possible online analytical technique to categorize pieces of cured ham on the industrial production line based on their maximum sodium content. Stifle muscle was selected for the development of the NIRS prediction models because it is the one with the highest sodium content and the easiest in terms of accessibility for spectral measurement. In the study, samples with varying thicknesses were taken. The suitability of this method is demonstrated when a 5 mm sample is used for the construction of the model, obtaining the best fit with an R2cv of 92% and a prediction error of 0.11% sodium that coincides with the error of the reference method. In conclusion, a method is proposed for the direct determination of sodium content on the production line which allows the different pieces of ham to be quickly categorized according to their salt content.

Electrolyte Effects on CO2 Electrochemical Reduction to CO.

ConspectusThe electrochemical reduction of CO2 (CO2RR) constitutes an alternative to fossil fuel-based technologies for the production of fuels and commodity chemicals. Yet the application of CO2RR electrolyzers is hampered by low energy and Faradaic efficiencies. Concomitant electrochemical reactions, like hydrogen evolution (HER), lower the selectivity, while the conversion of CO2 into (bi)carbonate through solution acid–base reactions induces an additional concentration overpotential. During CO2RR in aqueous media, the local pH becomes more alkaline than the bulk causing an additional consumption of CO2 by the homogeneous reactions. The latter effect, in combination with the low solubility of CO2 in aqueous electrolytes (33 mM), leads to a significant depletion in CO2 concentration at the electrode surface.The nature of the electrolyte, in terms of pH and cation identity, has recently emerged as an important factor to tune both the energy and Faradaic efficiency. In this Account, we summarize the recent advances in understanding electrolyte effects on CO2RR to CO in aqueous solutions, which is the first, and crucial, step to further reduced products. To compare literature findings in a meaningful way, we focus on results reported under well-defined mass transport conditions and using online analytical techniques. The discussion covers the molecular-level understanding of the effects of the proton donor, in terms of the suppression of the CO2 gradient vs enhancement of HER at a given mass transport rate and of the cation, which is crucial in enabling both CO2RR and HER. These mechanistic insights are then translated into possible implications for industrially relevant cell geometries and current densities.

The sampling interface—A critical Theory of Sampling success factor in process sampling and PAT

In the process industry arena, analytical endeavors are today well served by the Process Analytical Technology (PAT) framework, offering a plentitude of on-line analytics, mostly spectroscopic: UV-VIS, NIR, RAMAN, NMR, “acoustic chemometrics” a.o. This context is generally considered satisfactory, but there is a major catch. The present paper focuses on a fundamental feature in process sampling, the link between an on-line analytical technique and a moving stream of matter, which is to be characterised, monitored, and analysed. A process sampling operation can serve many objectives; process regulation, product or interim product characterisation, optimisation of raw material consumption, maximizing energy efficiency, pollution, and environmental impact management ‒ or process, plant, company, corporation decision making at supervisor and management levels concerning economics and risk management. All these objectives can only be meaningfully undertaken if based onrelevant information, that is, if based on reliable analytical data, which in turn is 100% dependent upon representative samples, or representative sensor signals. The singular common element in all of this is the process sampling interface. This paper develops a critique of most current interfaces, with a scathing verdict: the dual role of the process sampling interface as both delineating an appropriate aliquot volume while facilitating the specific analytical technique, has largely been overlooked, with a significant negative effect that is spelled out in full detail across implemented solutions across widely different application sectors. Most current process sampling interfaces do not comply with TOS’ demands, putting representativity severely at risk for heterogenous materials.

A Novel Methodology for Online Analysis of Amine Solution Degradation Caused by Fly Ash

Two research goals were set for this study. (1) The first goal was to develop a reliable and cost-effective online analytical technique to measure amine solvent concentration, loading, and to quantify the amine degradation process based on Gas Chromatography (GC). (2) The second goal was the investigation of amine degradation in the presence of fly ash, which includes: the identification of proper chemistry of degradation; and, the identification and quantification of the degradation products of the amines. For this study, aqueous monoethanolamine (MEA) and aqueous methyldiethanolamine (MDEA) have been selected. To accomplish the first goal, an online analytical technique to quantify the amine solvent chemistry based on Gas Chromatography (GC) was developed and set up in the lab. An automatic liquid sample injection system was attached to the GC to study the impact of the concentration of fly ash on the degradation process of two well-known amines (MEA and MDEA) by measuring the concentrations of amine, water and carbon dioxide (CO2). The flow system was equipped with filters to avoid the introduction of large particles into the GC column. A solvent back-flush system was used to allow for automated cleaning of the particulate filters. GC was then calibrated for the amine and water using various concentrations of aqueous amines (MEA and MDEA), and various CO2 loaded aqueous MDEA solutions and aqueous solutions of ammonium bicarbonate (NH4HCO3) were used to calibrate the GC for quantification of CO2 using a Total Organic Carbon / Total Inorganic Carbon (TOC/TIC) analyzer. To accomplish the second goal, two kinds of fly ash samples were collected from a coal burning power plant. Fly ash samples collected from the power plant were analyzed by SGS Canada Inc. ASTM methods were used to estimate the ash percentage, moisture content and elemental composition of the fly ash (silica and other metal oxides). A lab scale experimental setup was designed and developed to observe the influence of fly ash on amine-based solvents (MEA or MDEA) degradation.

Current Trends in Fully Automated On-Line Analytical Techniques for Beverage Analysis

The determination of target analytes in complex matrices such as beverages requires a series of analytical steps to obtain a reliable analysis. This critical review presents the current trends in sample preparation techniques based on solid phase extraction miniaturization, automation and on-line coupling. Techniques discussed include solid-phase extraction (SPE), solid-phase microextraction (SPME), in-tube solid-phase microextraction (in-tube SPME) and turbulent-flow chromatography (TFC). Advantages and limitations, as well as several of their main applications in beverage samples are discussed. Finally, fully automated on-line systems that involve extraction, chromatographic separation, and tandem mass spectrometry in one-step are introduced and critically reviewed.

On-line prediction of sodium content in vacuum packed dry-cured ham slices by non-invasive near infrared spectroscopy

In the present study, non-invasive near infrared spectroscopy (NIRS) was evaluated as a potential on-line analytical technique to predict the sodium content in dry-cured ham slices. Samples of 310 packages were scanned by applying a remote fibre-optic probe to the surface of the slices, at different temperatures, with no previous manipulation. The sodium content of the meat samples was determined by a reference method based on Inductively Coupled Plasma Atomic Emission Spectrophotometry (ICP-AES) after chemical digestion. Partial least squares (PLS) regression was used as a chemometrics method to perform the calibrations. The models yielded acceptable results with cross validation correlation coefficients (R2CV) determined 86.2–90.2%. The prediction capacity reached in the external validation was 3.63, with a standard prediction error of 0.12% Na. These results show that NIR measurements could be implemented on the packaging line of dry-cured ham slices to provide accurate and relevant information about the sodium content of each packaged products.

Regulation of the cerebral circulation: bedside assessment and clinical implications.

Regulation of the cerebral circulation relies on the complex interplay between cardiovascular, respiratory, and neural physiology. In health, these physiologic systems act to maintain an adequate cerebral blood flow (CBF) through modulation of hydrodynamic parameters; the resistance of cerebral vessels, and the arterial, intracranial, and venous pressures. In critical illness, however, one or more of these parameters can be compromised, raising the possibility of disturbed CBF regulation and its pathophysiologic sequelae. Rigorous assessment of the cerebral circulation requires not only measuring CBF and its hydrodynamic determinants but also assessing the stability of CBF in response to changes in arterial pressure (cerebral autoregulation), the reactivity of CBF to a vasodilator (carbon dioxide reactivity, for example), and the dynamic regulation of arterial pressure (baroreceptor sensitivity). Ideally, cerebral circulation monitors in critical care should be continuous, physically robust, allow for both regional and global CBF assessment, and be conducive to application at the bedside. Regulation of the cerebral circulation is impaired not only in primary neurologic conditions that affect the vasculature such as subarachnoid haemorrhage and stroke, but also in conditions that affect the regulation of intracranial pressure (such as traumatic brain injury and hydrocephalus) or arterial blood pressure (sepsis or cardiac dysfunction). Importantly, this impairment is often associated with poor patient outcome. At present, assessment of the cerebral circulation is primarily used as a research tool to elucidate pathophysiology or prognosis. However, when combined with other physiologic signals and online analytical techniques, cerebral circulation monitoring has the appealing potential to not only prognosticate patients, but also direct critical care management.

Fine and Ultrafine Particles in the Vicinity of Industrial Activities: A Review

This review synthesizes the existing knowledge on the characteristics of PM2.5 at sites under the direct influence of industrial emissions, with a specific focus on their morphology, size distributions and chemical composition. Results from online and off-line analytical techniques indicate a high temporal and spatial variability of mass size distribution and chemical composition depending on the type of industrial processes, the sampling distances and frequencies, and the meteorological conditions. Tracers of specific activities have been identified in a number of studies and may help to provide estimates of the relative contribution of pollutant sources from heavily industrialized areas.

Membrane Introduction Mass Spectrometry (MIMS): A Versatile Tool for Direct, Real‐Time Chemical Measurements

Membrane introduction (or inlet) mass spectrometry (MIMS) is a direct, on-line analytical technique, requiring that the mass spectrometer resolve analytes in the mixture based upon their m/z, their ionization characteristics and/or by mass spectrometry techniques. The coupling of semi-permeable membranes to mass spectrometers enables rapid, direct analysis with minimal sample handling as well as continuous monitoring applications. It can be employed to follow dynamic changes in trace analyte concentrations and is therefore well suited for applications such as environmental monitoring, process control and /or in-situ/in-vivo analysis. In this special feature article, Erik Krogh and Chris Gill present recent developments and applications of MIMS variants using examples from their research and collaborations with others and comment on the future for this emerging ‘old dog with new tricks’. Christopher Gill and Erik Krogh have been the main forces behind the establishment of the Applied Environmental Research Laboratory at Vancouver Island University (Nanaimo, BC, Canada).

Delicate polydimethylsiloxane hollow fibre membrane interfaces for condensed phase membrane introduction mass spectrometry (CP‐MIMS)

On-line analytical techniques such as condensed phase membrane introduction mass spectrometry (CP-MIMS) permit direct and rapid analyte measurements in complex samples. Direct, rapid analytical methods are desirable because they eliminate potential contamination and/or dilution from sample workup steps, facilitate rapid sample screening and allow 'real-time' monitoring applications. PDMS hollow fibre membrane (HFM) flow cell interfaces (215 µm, 35 µm, and 0.5 µm thick composite) were coupled with an electrospray ionization (ESI) triple quadrupole mass spectrometer. A simultaneous push/pull methanol acceptor phase delivery system and membrane mounting via epoxy potting ensured that the delicate membranes were not ruptured during construction or sample measurements. Both flow cell and direct insertion 'J-Probe' interfaces using the 0.5 µm thick composite PDMS HFM were utilized for direct naphthenic acid measurements. Delicate HFM CP-MIMS interfaces were used for the rapid screening and continuous, on-line monitoring of carboxylic acids and hydroxylated compounds directly in complex sample matrices under ambient conditions at pptr - ppb detection limits. Push/pull acceptor phase (methanol) delivery maintained ambient hydrostatic pressures within the HFMs, improving ESI stability and analytical sensitivity, especially with stopped acceptor flow operation. Signal response times less than 2 min were achieved for thin, composite PDMS HFMs at 30°C. The continuous monitoring of naphthenic acid degradation was demonstrated. Delicate PDMS HFM CP-MIMS interfaces were developed and used for the direct, on-line detection of low volatility, polar analytes in complex aqueous samples. Composite PDMS HFM interfaces yielded the best overall analytical performance improvements, and were used to demonstrate the direct measurement of naphthenic acids in complex aqueous samples.

A new online technique for the simultaneous measurement of the δ 13 C value of dissolved inorganic carbon and the δ 18 O value of water from a single solution sample using continuous-flow isotope ratio mass spectrometry

The oxygen isotope study of water reservoirs (δ(18)OH2O values) and the carbon isotope study of dissolved inorganic carbon (δ(13)CDIC values) are powerful tools to decipher Earth's past and present environmental changes. This study presents a novel online analytical technique, namely the DIC evolved CO2 Gas Equilibration Method (DIC-CO2-GEM), in which the δ(18)OH2O and δ(13)CDIC values can be simultaneously determined from a single solution sample. The DIC-CO2-GEM measures both δ(18)OH2O and δ(13)CDIC values concurrently by combining the fundamental principles of the classic CO2-H2O equilibration and gas evolution methods, respectively. Phosphoric acid is used to convert dissolved inorganic carbon in a solution sample of 0.2 mL into gaseous CO2, which is then equilibrated with the solution at 25 °C. The oxygen and carbon isotope compositions are subsequently determined via continuous-flow isotope ratio mass spectrometry from the single solution sample. Results obtained employing the DIC-CO2-GEM are in good agreement (<± 0.07‰ for δ(18)OH2O values and < < ± 0.1‰ for δ(13)CDIC values) with those acquired using each of the traditional techniques. For both oxygen and carbon isotope measurements, an addition of 0.01 mL phosphoric acid yields the most consistent results between our technique and the traditional methods. Devised to combine the traditional approaches independently assessing δ(18)OH2O and δ(13)CDIC values, the DIC-CO2-GEM is less complex and highly efficient. It preserves the modern precision requirements for oxygen (± 0.09‰) and carbon (± 0.18‰) isotope analyses while accurately measuring both parameters simultaneously. This innovative method generates an abundance of data while minimizing resources and is suitable for a variety of practical applications.

Detection of Anisakid Larvae in Cod Fillets by UV Fluorescent Imaging Based on Principal Component Analysis and Gray Value Analysis

Anisakid larvae are regarded as an important hazard in marine products, and demand is growing for on-line nondestructive analytical techniques for effective monitoring of these parasites. A UV fluorescent imaging was developed for detection of the third-stage anisakid larvae in marine fishes, and different processing methods were investigated and optimized based on principal component and gray value analyses. Using cod fillets as samples, the efficiency of the developed technique was evaluated, and the overall detection ratio was greater than 80 % . These results indicate a promising application of UV fluorescent imaging as an effective and nondestructive technique for identification of anisakid larvae in fishery products.

Integration of Process Analytical Technology Tools in Pilot-Plant Setups for the Real-Time Monitoring of Crystallizations and Phase Transitions

In this study it was demonstrated that the usage of an access unit connected to a pump-around loop cycle is a good solution for the integration of various online analytical measurement techniques i...

Measurement and control of bioprocesses.Preface.

Automated Measurement and Monitoring of Bioprocesses: Key Elements of the M3C Strategy, by Bernhard Sonnleitner.- Automatic Control of Bioprocesses, by Marc Stanke, Bernd Hitzmann.- An Advanced Monitoring Platform for Rational Design of Recombinant Processes, by G. Striedner, K. Bayer.- Modelling Approaches for Bio-Manufacturing Operations, by Sunil Chhatre.- Extreme Scale-Down Approaches for Rapid Chromatography Column Design and Scale-Up During Bioprocess Development, by Sunil Chhatre.- Applying Mechanistic Models in Bioprocess Development, by Rita Lencastre Fernandes, Vijaya Krishna Bodla, Magnus Carlquist, Anna-Lena Heins, Anna Eliasson Lantz, Gurkan Sin and Krist V. Gernaey.- Multivariate Data Analysis for Advancing the Interpretation of Bioprocess.- Measurement and Monitoring Data, by Jarka Glassey.- Design of Pathway-Level Bioprocess Monitoring and Control Strategies Supported by Metabolic Networks, by Ines A. Isidro, Ana R. Ferreira, Joao J. Clemente, Antonio E. Cunha, Joao M. L. Dias, Rui Oliveira.- Knowledge Management and Process Monitoring of Pharmaceutical Processes in the Quality by Design Paradigm, by Anurag S Rathore, Anshuman Bansal, Jaspinder Hans.- The Choice of Suitable Online Analytical Techniques and Data Processing for Monitoring of Bioprocesses, by Ian Marison, Siobhan Hennessy, Roisin Foley, Moira Schuler, Senthilkumar Sivaprakasam, Brian Freeland.

Mass Spectrometry “Sensor” forin VivoAcetylcholine Monitoring

Developing sensors for in vivo chemical monitoring is a daunting challenge. An alternative approach is to couple sampling methods with online analytical techniques; however, such approaches are generally hampered by lower temporal resolution and slow analysis. In this work, microdialysis sampling was coupled with segmented flow electrospray ionization mass spectrometry (ESI-MS) to perform in vivo chemical monitoring. The use of segmented flow to prevent Taylor dispersion of collected zones and rapid analysis with direct ESI-MS allowed 5 s temporal resolution to be achieved. The MS "sensor" was applied to monitor acetylcholine in the brain of live rats. The detection limit of 5 nM was sufficient to monitor basal acetylcholine as well as dynamic changes elicited by microinjection of neostigmine, an inhibitor of acetylcholinesterase, that evoked rapid increases in acetycholine and tetrodotoxin, a blocker of Na(+) channels, that lowered the acetylcholine concentration. The versatility of the sensor was demonstrated by simultaneously monitoring metabolites and infused drugs.

A spectrophotometric study of cerium IV and chromium VI species in nuclear fuel reprocessing process streams

Nuclear fuel reprocessing schemes such as PUREX and UREX utilise HNO3 media. An understanding of the corrosion of process engineering materials such as stainless steel in such media is a major concern for the nuclear industry. Two key species are cerium and chromium which, as Ce(IV), Cr(VI), may act as corrosion accelerants. An on-line analytical technique for these quantities would be useful for determining the relationship between corrosion rate and [Ce(IV)] and [Cr(VI)]. Consequently, a strategy for simultaneous quantification of Ce(IV), Cr(VI) and Cr(III) in the presence of other ions found in average burn-up Magnox / PWR fuel reprocessing stream (Fe, Mg, Nd, Al) is being developed.This involves simultaneous UV-vis absorbance measurement at 620, 540, 450 nm, wavelengths where Ce and Cr absorb but other ions do not. Mixed solutions of Cr(VI) and Ce(IV) are found to present higher absorbance values at 540 nm than those predicted from absorbances recorded from single component solutions of those ions. This is attributed to the formation of a 3:1 Cr(VI)-Ce(IV) complex and we report on the complexation and UV-visible spectrophotometric characteristics of this species. To the best of our knowledge this is the first experimental study of this complex in aqueous nitric acid solution systems.

Quality Evaluation and Quality Control of Botanicals and Traditional Chinese Medicine

This presentation will introduce a systemic strategy and relative technologies for the quality evaluation of Traditional Chinese Medicine (TCM), including the identification and differentiation of botanicals and also the quality standard of TCM products. The emphasis will focus on the quality control of manufacture of TCM products, especially to introduce an application of NIRS online analytical technique and quality-based control system into the extraction procedure of TCM. The system hardware was composed of the extraction equipment, the online sample pre-treatment subsystem, the NIRS subsystem, the online NIRS analysis and intelligent control subsystem, and the automatic control subsystem. A diagram of the system is shown in Fig. 1. The whole system includes cooperative-working hardware and software components. The extraction process of TCM was analyzed using online NIRS, and the results demonstrated that NIRS was feasible to be applied to online monitoring and controlling in the manufacturing of TCM. Based on the online NIRS analysis technology, the real-time monitoring of the effective components or indicative components in the extraction procedure, the analysis of the extraction ratios, the diagnosis of the extraction procedure, and the real-time feedback control based on the quality status were actualized.

Dynamics of retronasal aroma perception during consumption: Cross-linking on-line breath analysis with medico-analytical tools to elucidate a complex process

An analytical concept is developed for the on-line investigation of the temporal and spatial dynamics in ortho- and retronasal odor perception. It aims at the elucidation of the relationship between the molecular level and perception during and after administration of a chemical stimulus. One basic principle is to apply precisely defined odorous stimuli, and to measure their temporal characteristics using an on-line analytical technique, proton-transfer reaction mass spectrometry (PTR-MS). In parallel, the subjects’ response to the stimulus can be investigated with electrophysiological and psychophysical techniques. This approach can be modified to elucidate the processes involved in the perception of food and drinks. Panellists may take an active role as they modulate chemosensations with certain patterns of mastication/swallowing. Using videofluoroscopy or real-time magnetic resonance imaging these mechanical oropharyngeal processes may be visualized.

HDI: Integrating Health Data and Tools

Health systems globally are looking to make better use of the data they capture in order to improve their services, both for service provision and clinical outcome. One way of doing this is to integrate existing data sources. However, major technical and legal questions exist concerning data integration, data quality, data security and privacy in health data usage. In this paper, we present the HDITM tool, that is currently under development at the e-Health Research Centre. Firstly we describe the HDITM architecture and its data integration capabilities. We then consider two of its core capabilities (1) privacy-preserving similarity linkage and (2) on-line analytical techniques and report generating. Finally, we discuss how HDI functionality can be used to provide the capabilities of a knowledge based medical system. The e-Health Research Centre is currently working with the Queensland Health department to deploy the software in practice.

Achiral–chiral LC/LC–MS/MS coupling for determination of chiral discrimination effects in phenprocoumon metabolism

Many physiological processes show a high degree of stereoselectivity, including the metabolism of xenobiotics as catalyzed by cytochrome P450 enzymes. An analysis of these chiral discrimination effects in drug metabolism is essential for an in-depth understanding of metabolic pathways that differ between enantiomers of a given chiral drug or metabolite thereof. Achiral chromatographic separation and structural identification followed by chiral analysis of metabolites from blood specimens usually requires a time-consuming multistage analytical technique. In an effort to optimize such a complicated analytical scheme, a novel two-dimensional online achiral–chiral liquid chromatography–tandem mass spectrometry (LC/LC–MS/MS) coupling method was developed by using a peak parking technique in combination with a makeup flow system. Metabolites were separated in the first dimension using a C18 reversed-phase system. A makeup eluent of water/methanol (95/5) was split into the flow before storing the metabolites separately on chiral cartridges. Subsequently, the metabolite enantiomers were eluted backward onto the analytical chiral column and separated, and the ratio of enantiomers was determined. The method was successfully validated with respect to limit of detection, linearity, intra- and interday accuracy, and precision. In the course of a human volunteer study investigating the influence of CYP (cytochrome) 2C9 genetic polymorphism on phenprocoumon (PPC) metabolism, we used this new two-dimensional online analytical technique for the analysis of PPC metabolites in plasma. The enantiomeric forms of 4′-, 6-, and 7-hydroxy-PPC metabolites as well as two novel metabolites were identified, and the ratio of the enantiomers was calculated. We found that the enantiomeric ratio for the different metabolites in the plasma sample of each measured individual differs markedly from a nearly 100% chiral discrimination for the two new putative metabolites. This new analytical coupling method possesses general utility in the analysis of chiral discrimination effects, particularly as it relates to pharmacokinetics and dynamics, a scientific field that is rapidly becoming an area of concern and interest.