Adaption of a fragment analysis technique to an automated high-throughput multicapillary electrophoresis device for the precise qualitative and quantitative characterization of microbial communities

The analysis of microbial communities is of increasing importance in life sciences and bioengineering. Traditional techniques of investigations like culture or cloning methods suffer from many disadvantages. They are unable to give a complete qualitative and quantitative view of the total amount of microorganisms themselves, their interactions among each other and with their environment. Obviously, the determination of static or dynamic balances among microorganisms is of fast growing interest. The generation of species specific and fluorescently labeled 16S ribosomal DNA (rDNA) fragments by the terminal restriction fragment length polymorphism (T-RFLP) technique is a suitable tool to overcome the problems other methods have. For the separation of these fragments polyacrylamide gel sequencers are preferred as compared to capillary sequencers using linear polymers until now because of their higher electrophoretic resolution and therefore sizing accuracy. But modern capillary sequencers, especially multicapillary sequencers, offer an advanced grade of automation and an increased throughput necessary for the investigation of complex communities in long-time studies. Therefore, we adapted a T-RFLP technique to an automated high-throughput multicapillary electrophoresis device (ABI 3100 Genetic Analysis) with regard to a precise qualitative and quantitative characterization of microbial communities.     

Solid-state sensors and their applications in consumer electronics and home appliances in Japan

Rapid progress in semiconductor technology, involving microcomputers and VLSI, has increased the capabilities of electronic equipment used in industry. Requirements for consumer products are (1) comfort and convenience; (2) ‘intelligence’, (3) energy and resources saving and (4) safety. In order to realize these requirements, microcomputers and sensors have been introduced into consumer electronics and home appliances. Mechanical sensors, radiation sensors, temperature sensors and magnetic sensors have been used. There is now a growing demand for small, reliable and low-cost solid state sensors capable of interfacing with natural events. A review of some typical sensor applications for microcomputer-based equipment in consumer electronics and home appliances is presented.     

On-Line Derivatization of N-acetylcysteine Using Ethyl-Propiolate as a Novel Advantageous Reagent and Sequential Injection Analysis

This study reports a novel automated assay for the determination of N-acetylcysteine (NAC). The method is based upon the on-line derivatization of the analyte with a new reagent, ethyl-propiolate (EPL), to form a UV-absorbing derivative. The reaction is fast, proceeds in aqueous solutions under mild conditions and is, therefore, ideal for automation using sequential injection analysis. All major chemical and instrumental variables were examined thoroughly. The assay was validated for linearity, range, LOD-LOQ, within and day-to-day precision, selectivity, and accuracy. The experiments confirmed its suitability for the reliable quality control of NAC-containing formulations at a sampling rate of 80 h^?1.     

Automation and Standardization—A Coupled Approach towards Reproducible Sample Preparation Protocols for Nanomaterial Analysis

Whereas the characterization of nanomaterials using different analytical techniques is often highly automated and standardized, the sample preparation that precedes it causes a bottleneck in nanomaterial analysis as it is performed manually. Usually, this pretreatment depends on the skills and experience of the analysts. Furthermore, adequate reporting of the sample preparation is often missing. In this overview, some solutions for techniques widely used in nano-analytics to overcome this problem are discussed. Two examples of sample preparation optimization by automation are presented, which demonstrate that this approach is leading to increased analytical confidence. Our first example is motivated by the need to exclude human bias and focuses on the development of automation in sample introduction. To this end, a robotic system has been developed, which can prepare stable and homogeneous nanomaterial suspensions amenable to a variety of well-established analytical methods, such as dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), field-flow fractionation (FFF) or single-particle inductively coupled mass spectrometry (sp-ICP-MS). Our second example addresses biological samples, such as cells exposed to nanomaterials, which are still challenging for reliable analysis. An air–liquid interface has been developed for the exposure of biological samples to nanomaterial-containing aerosols. The system exposes transmission electron microscopy (TEM) grids under reproducible conditions, whilst also allowing characterization of aerosol composition with mass spectrometry. Such an approach enables correlative measurements combining biological with physicochemical analysis. These case studies demonstrate that standardization and automation of sample preparation setups, combined with appropriate measurement processes and data reduction are crucial steps towards more reliable and reproducible data.     

Quantum Control of Gas‐Phase and Liquid‐Phase Femtochemistry

Active control of chemical reactions on a microscopic (molecular) level, that is, the selective breaking or making of chemical bonds, is an old dream. However, conventional control agents used in chemical synthesis are macroscopic variables such as temperature, pressure or concentration, which gives no direct access to the quantum‐mechanical reaction pathway. In quantum control, by contrast, molecular dynamics are guided with specifically designed light fields. Thus it is possible to efficiently and selectively reach user‐defined reaction channels. In the last years, experimental techniques were developed by which many breakthroughs in this field were achieved. Femtosecond laser pulses are manipulated in so‐called pulse shapers to generate electric field profiles which are specifically adapted to a given quantum system and control objective. The search for optimal fields is guided by an automated learning loop, which employs direct feedback from experimental output. Thereby quantum control over gas‐phase as well as liquid‐phase femtochemical processes has become possible. In this review, we first discuss the theoretical and experimental background for many of the recent experiments treated in the literature. Examples from our own research are then used to illustrate several fundamental and practical aspects in gas‐phase as well as liquid‐phase quantum control. Some additional technological applications and developments are also described, such as the automated optimization of the output from commercial femtosecond laser systems, or the control over the polarization state of light on an ultrashort timescale. The increasing number of successful implementations of adaptive learning techniques points at the great versatility of computer‐guided optimization methods. The general approach to active control of light–matter interaction has also applications in many other areas of modern physics and related disciplines.     

Design and use of electrochemical sensors in enantioselective high throughput screening of drugs. A minireview

The importance of reliable detection systems for enantiomeric assays increases with the necessity of high throughput screening analysis of raw materials for the pharmaceutical industry. The utilization of electrochemical sensors in enantioselective analysis is an accurate and precise alternative to chromatographic techniques. The reliability of the response characteristics as well as of the analytical information obtained by using electrochemical sensors is strictly correlated with the design of the sensors. The designs evaluated for sensors have been based on PVC, imprinting polymers and carbon paste matrices. Among these, carbon paste sensors have been the most reliable and have been utilized for the construction of potentiometric, enantioselective membrane electrodes as well as for amperometric biosensors, and immunosensors. There are two ways to use the electrochemical sensors in enantioselective screening analysis: selective binding and catalyst selectivity. A molecule with a special chemical architecture is required for selective binding: a lock for a key. The high reliability of analytical information obtained using these sensors has made possible the automation of potentiometric and amperometric techniques by integration of enantioselective sensors as detectors in flow injection analysis and sequential injection analysis techniques.     

Plasma protein fractions in healthy blood donors quantitated by an automated multicapillary electrophoresis system

During the last decade, capillary electrophoresis (CE) has emerged as an important alternative to traditional analysis of serum and plasma proteins by agarose or celluloseacetate electrophoresis. CE analysis of plasma proteins can now be fully automated and also includes bar-code identification of samples, preseparation steps, and direct post-separation quantitation of individual peaks, which permits short assay times and high throughput. For laboratory work, it is important to have reference values from healthy individuals. Therefore, plasma samples from 156 healthy blood donors (79 females and 77 males) have been analyzed with the Capillarys instrument and the new high resolution buffer, which yields higher resolution than the beta1-beta2+ buffer. Albumin concentrations in samples are measured using nephelometry in order to assign protein concentrations to each peak. The 2.5 and 97.5 percentiles for both the percentages of different peaks and the protein concentrations in the peaks are calculated according to the recommendations of the International Federation of Clinical Chemistry on the statistical treatment of reference values. The Capillarys instrument is a reliable system for plasma protein analysis, combining advantages of full automation with high analytical performances and throughput.     

Flow injection spectrophotometric determination of calcium, phosphate and chloride ions in milk.

Flow injection procedures for the determination of calcium, phosphate and chloride ions in milk samples are described. The reactions are based on the formation of coloured complexes and their spectrophotometric monitoring. A sample pre-treatment with acetate buffer was carried out owing to the complexity of the sample matrix. For chloride, a rapid and reliable automated procedure for direct measurement of its content in milk (using a dialyser to eliminate interferences) is also described. After optimizing the sample pre-treatment and flow injection variables, the procedures were applied to commercial milk; the results obtained agreed satisfactorily with those of the reference methods. With 50 mm3 samples, a working range of 0-15 ppm for calcium, 50-150 ppm for phosphate and 5-100 ppm for chloride is covered with a precision of better than 1.1%. The sample throughput was higher than 50 samples h-1. These preliminary experiments are the basis for the automation of the determination of calcium, phosphate and chloride ions using a computer-controlled, self-designed and laboratory-built autoanalyser.     

Application of quantum dots as analytical tools in automated chemical analysis: A review

Colloidal semiconductor nanocrystals or quantum dots (QDs) are one of the most relevant developments in the fast-growing world of nanotechnology. Initially proposed as luminescent biological labels, they are finding new important fields of application in analytical chemistry, where their photoluminescent properties have been exploited in environmental monitoring, pharmaceutical and clinical analysis and food quality control. Despite the enormous variety of applications that have been developed, the automation of QDs-based analytical methodologies by resorting to automation tools such as continuous flow analysis and related techniques, which would allow to take advantage of particular features of the nanocrystals such as the versatile surface chemistry and ligand binding ability, the aptitude to generate reactive species, the possibility of encapsulation in different materials while retaining native luminescence providing the means for the implementation of renewable chemosensors or even the utilisation of more drastic and even stability impairing reaction conditions, is hitherto very limited. In this review, we provide insights into the analytical potential of quantum dots focusing on prospects of their utilisation in automated flow-based and flow-related approaches and the future outlook of QDs applications in chemical analysis.     

Automated sample treatment with the injection of large sample volumes for the determination of contaminants and metabolites in urine

This work reports the development of a simple and automated method for the quantitative determination of several contaminants (triazine, phenylurea, and phenoxyacid herbicides; carbamate insecticides and industrial chemicals) and their metabolites in human urine with a simplified sample treatment. The method is based on the online coupling of an extraction column with RP LC separation–UV detection; this coupling enabled fast online cleanup of the urine samples, efficiently eliminating matrix components and providing appropriate selectivity for the determination of such compounds. The variables affecting the automated method were optimized: sorbent type, washing solvent and time, and the sample volume injected. The optimized sample treatment reported here allowed the direct injection of large volumes of urine (1500 μL) into the online system as a way to improve the sensitivity of the method; limits of detection in the 1–10 ng/mL range were achieved for an injected volume of 1500 μL of urine, precision being 10% or better at a concentration level of 20 ng/mL. The online configuration proposed has advantages such as automation (all the steps involved in the analysis – injection of the urine, sample cleanup, analyte enrichment, separation and detection – are carried out automatically) with high precision and sensitivity, reducing manual sample manipulation to freezing and sample filtration.     

新型荧光光纤免疫磁珠流动分析系统研究（I）

将荧光免疫分析技术、光纤传感技术、流动注射技术和免疫磁珠分离技术联用,建立了一种新型荧光光纤免疫磁珠流动分析系统,并采用荧光素异硫氰酸酯（ＦＩＴＣ）对系统性能进行考察,结果表明该分析系统设计合理,性能可靠,在临床、环保等领域有广泛的应用前景。     

Breath sampling control for medical application

Sampling of breath under human control or automated control with sensors was combined with chemical determination of a synthetic sample using multi-capillary column ion mobility spectrometry to measure quantitative variability. Variation was 19% with an automated inlet and 33% with human control. Sensors to operate an automated inlet were also evaluated with human subjects and included carbon dioxide (CO₂), flow (direction and velocity), volume (integrated from the flow rate) and humidity, all operating in the mainstream of exhaled air. The flow sensor provided a measure of sampling of breath from the upper airways and other sensors gauged exclusive sampling of the end-tidal volume as well. Sensors for volume and CO₂ exhibited identical profiles, using appropriate threshold values, in reference to inspiration and expiration. A sensor for humidity lagged inspiration and expiration with a delay of 300 ms and therefore is diminished in value. The sensors recommended for an automated inlet for breath sampling are CO₂ and the exhaled or tidal volume though tidal volume varies significantly with personal physiognomy. This necessitates an evaluation of a subject to establish a threshold setting and CO₂ is the single best parameter providing the availability of sensor signal within 50 ms.     

新型荧光光纤免疫磁珠流动分析系统研究（Ⅰ）

将荧光免疫分析技术、光纤传感技术、流动注射技术和免疫磁珠分离技术联用,建立了一种新型荧光光纤免疫磁珠流动分析系统,并采用荧光素异硫氰酸酯（FITC）对系统性能进行考察,结果表明该分析系统设计合理,性能可靠,在临床、环保等领域有广泛的应用前景。     

Spatial and temporal resolution in cryo-electron microscopy—A scope for nano-chemistry

Cryo-electron microscopy has evolved in an established approach to study the structure of bio-colloids. Recent developments in instrumentation and automation, often demanded by life sciences, made cryo-EM a general tool in colloid chemistry. Recently improved instrumentation for vitrification has resulted in reliable and reproducible preparation of specimen in water and other solvents. A dynamic approach, following processes in time is gaining importance and a time resolution up to 1 ms is expected to become general available. With improved instrumentation and automation 3D reconstructions by cryo-EM tomography are becoming routinely accessible. Tomography as such or in conjunction with time resolved microscopy is expected to give new insights in (macro)molecular assembly/disassembly mechanisms and thus become an essential tool in nano-chemistry.     

光电化学传感器的研究进展

光电化学传感器以光作为激发源,以光电流或光电压作为检测信号,具有响应快速、灵敏度高、设备简单等特点,目前已在环境、食品、医学等多个领域的分析测试中得到广泛应用。该文阐述了光电转换材料与光电化学传感器的制备方法,介绍了光电化学传感器的原理和分类。光电化学传感器包含光寻址电位型传感器和电流型光电化学传感器,其中,电流型光电化学传感器由于优良的光电性能、检出限低、所需材料低廉且易加工等优势而被广泛应用。文中着重介绍了电流型光电化学传感器在金属离子、有机污染物、核酸、蛋白质、细胞等方面的应用,并对光电化学传感器的发展前景进行了展望。     

Miniaturized electrochemical sensors and their point-of-care applications

Most of the current analytical methods depend largely on laboratory-based analytical techniques that require expensive and bullky equipment,potentially incur costly testing,and involve lengthy detection processes.With increasing requirements for point-of-care testing(POCT),more attention has been paid to miniaturized analytical devices.Miniaturized electrochemical(MEC)sensors,including different material-based MEC sensors(such as DNA-,paper-,and screen electrode-based),have been in strong demand in analytical science due to their easy operation,portability,high sensitivity,as well as their short analysis time.They have been applied for the detection of trace amounts of target through measuring changes in electrochemical signal,such as current,voltage,potential,or impedance,due to the oxidation/reduction of chemical/biological molecules with the help of electrodes and electrochemical units.MEC sensors present great potential for the detection of targets including small organic molecules,metal ions,and biomolecules.In recent years,MEC sensors have been broadly applied to POCT in various fields,including health care,food safety,and environmental monitoring,owing to the excellent advantages of electrochemical(EC)technologies.This review summarized the state-of-the-art advancements on various types of MEC sensors and their applications in POCT.Furthermore,the future perspectives,opportunities,and challenges in this field are also discussed.     

Engineering upgrades to the Radionuclide Aerosol Sampler/Analyzer for the CTBT International Monitoring System

The Radionuclide Aerosol Sampler/Analyzer (RASA) is an automated collection and analysis system designed for aerosol radionuclide monitoring for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The advantages of an automated system include minimal need for human intervention and consistent analytical data. However, maintainability and down time issues threaten this utility, even for systems with over 90 % data availability. Engineering upgrades to the RASA are currently being pursued to address these issues, as well as measures relevant to technical lessons learned from the Fukushima nuclear power plant event. Current work includes a new automation control unit and other potential improvements such as alternative detector cooling and sampling options. This paper presents the current state of upgrades and improvements under investigation.     

Modelling of glass transition and molecular weight distribution in emulsion and suspension copolymerisation

SUMMARY. Modelling of emulsion copolymerisation is now more and more used for both mechanistic investigations and process control. Many specific characteristics of monomers, as well as polymerisation in heterogeneous medium can be quite accurately taken into account (temperature, pH, gel effect, crosslinking, inhibition, e.g.). However, a major problem is the extensive number of required parameters. But, depending on the main informations sought (kinetics, microstructure or properties), the number of parameters actually required can be decreased considerably by providing the computer either on-line or even off-line with global information on conversion and particle size, from reliable sensors. In addtion to kinetics, many distributions characterising the copolymers can be derived, which in turn lead to the accurate simulation and control of end-use properties such as glass transition or molecular weight distribution, as shown in this work.