The design of a battery-powered computer-controlled micropotentiostat is described. This micropotentiostat was developed as an amperometric detector for flow-injection analysis and high-performance liquid chromatography. It is based on micropower operational amplifiers, powered by two standard 9 V batteries, and controlled by a personal computer through a commercial Analog-to-Digital–Digital-to-Analog acquisition card. The analog and digital ports of the card allowed the implementation of automation in the selection of the measuring current range, baseline level compensation, and switching control of the batteries and electrochemical cell. The control software was written using the Turbo C++ language. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:53–58, 2000
An overview is made of the research work carried out in the author's laboratory, which is aimed at developing thin ion-selective chalcogenide membrane by induced cathodic electrodeposition onto inert conducting substrate at controlled potential of the membrane's components. The most important analytical results from implementing them in flow-injection analysis are presented. The basic principle and the major advantages of the electrochemical approach are outlined, with an emphasis on its contribution to obtaining new optimized membrane formulations such as Cu 2-x Se, CuAgSe, and Ag 2+ō Se 1−x Te x with improved dynamic and surface properties. Selected examples of the performance of the newly developed ion-selective flow-injection potentiometric (ISFIP) detectors for Cu(II), Hg(II), Ag(I), and CN − ions are considered with regard to lower linearity limit, selectivity, long-term stability as well as unique FIP applications. A comparison with the dynamic behavior of the commercially available ion-selective electrodes or their second-kind electrode counterparts prepared by anodic dissolution helps to reveal the aspects of the competitiveness of the proposed ISFIP detectors. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:216–225, 2000
An automated system for on-line determination of the dissolution rates of drug-delivery formulations to USP Methods I and II is described. The system employs UV–vis spectroscopy utilizing either a fiber-optic probe for direct determination or the option of on-line flow through analysis with prior filtration. The system is also capable of on-line flow through analysis utilizing both UV–vis and fluorescence detection and an off-line storage option for further sample processing. The system also comprises a complete IT solution including a simple user interface, data archival to an NT server, remote client server interrogation of the database, and automatic report generation. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:12–22, 2000
Laboratory Robotics and AutomationVolume 12, Issue 3 p. 127-128 Editorial notes: Flow injection analysis in the Pacific Rims: Examples with various degrees of automation Kate Grudpan, Corresponding Author Kate Grudpan kate@chiangmai.ac.th Department of Chemistry, Chiang Mai University, ThailandDepartment of Chemistry, Faculty of Science, and Institute for Science and Technology Research and Development, Chiang Mai University, Chiang Mai 50200 ThailandSearch for more papers by this author Kate Grudpan, Corresponding Author Kate Grudpan kate@chiangmai.ac.th Department of Chemistry, Chiang Mai University, ThailandDepartment of Chemistry, Faculty of Science, and Institute for Science and Technology Research and Development, Chiang Mai University, Chiang Mai 50200 ThailandSearch for more papers by this author First published: 14 July 2000 https://doi.org/10.1002/1098-2728(2000)12:3<127::AID-LRA1>3.0.CO;2-YCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume12, Issue3Special Issue: Flow‐Injection Analysis in The Pacific Rims2000Pages 127-128 RelatedInformation
The redox indicator, ferroin, tris(1,10-phenanthroline)iron(II) was incorporated into the perfluorosulfonated cation-exchange membrane Nafion and, together with optical fibers, a photodiode, and a light-emitting diode, was used for the construction of a redox optical sensor (optode). The optode was incorporated in the flow-through cell of a computer-controlled sequential injection (SI) system and used for the determination of ascorbic acid (vitamin C). A linear relationship between the logarithm of the ascorbic acid concentration and the membrane absorbance was obtained for the concentration range from 2.50 x 10(-3) to 1.00 x 10(-1) mol L-1 and a sample frequency of 17 h(-1). The concentration of ascorbic acid determined in a number of commercial pharmaceutical products agreed well with iodometric titration results. This result shows that the SI system incorporating the ferroin/Nafion optode is suitable for the automated analysis of ascorbic acid in pharmaceutical products. (C) 2000 John Wiley & Sons, Inc.
This work describes the software and hardware developed for implementation of on-line microwave-assisted sample digestion in an automated sequential-injection analysis (SIA) system. The system was completely developed with conventional equipment available in analytical laboratories. The software and hardware allows for the acquisition and manipulation of analytical signals and also for the synchronization of the actuation of each component. The assembled system is composed of a mixing valve, three solenoid valves, a commercial microwave oven, a peristaltic pump, and an ultrasonic bath. Additionally, it is possible to program 60 different events that can be controlled by the operator according to the requirement of analysis. The operator only needs to inject the samples, and the other steps are carried out by the automated SIA system. This system was applied for direct determination of Fe in white wines and presented a sampling frequency of 10 h−1. The limit of detection was 0.6 mg L−1, and an addition-recovery experiment led to recoveries in the 98–101% range. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:246–252, 2000
This work proposes a new approach for sediment analysis in which the sample is introduced as a slurry in an arc/spark emission spectrometer using a monosegmented system. The spectrometer has been modified to employ a 1024 photodiode-array detector capable of collecting intensities in a 18.7 nm wide wavelength window. Sediment slurries were prepared with 8.5-50 mg of the samples, grounded to a particle size less than 38 mu m, transferred to a 50 mL volumetric flask in which 1 mL of conc.HNO3 and 300 mu L of 10% m/v La (as La2O3; used as internal standard) were added. The slurry (25 mu L) was introduced into the monosegmented system and transported by an air stream to a graphite rod in the existing arc/spark source. About 40 samples can be analyzed per hour. Results for reference materials show acceptable accuracy and precision for the proposed method. (C) 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:46-52, 2000.
This article reports the use of solid phase spectrophotometry associated with flow injection technique for simultaneous determination of zinc and nickel with 1-(2-thiazolylazo)-2-naphthol (TAN) immobilized on a C18 bonded silica support in the concentration range from 0.30 to 1.0 μg mL −1 of both ions. The multicomponent analysis was implemented using the absorbance signals in different intervals of time in a flow injection analysis peak for each sample solution inserted into the analytical path. A partial least squares (PLS) algorithm for model construction was developed in QuickBasic 4.5 as a subrotine in order to assemble it in a data acquisition program, permitting the concentration estimation in real time. The proposed method was successfully applied to nickel and zinc determination in synthetic mixtures with analytical throughput of 43 samples per hour. The results obtained with the proposed method were compared with Inductively Coupled Plasma Atomic E Mission Spectrometry (ICP-AES) data, and the results agreed with 95% confidence level. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:305–311, 2000
A simple, fast, and low-cost flow-injection system is proposed for the determination of orthophosphate in digested plant material. The determination is based on the precipitation reaction of orthophosphate with 0.05 mol L−1 zinc solution in 0.05 mol L−1 triethanolamine buffer (TEA/TEAH+, pH 6.0) solution containing 0.025% (w/v) poly-(vinylalcohol). The zinc orthophosphate suspension produced was directly measured at 410 nm. Under the best experimental conditions, orthophosphate was determinated in the concentration range from 5 to 60 mg P L−1, and the relative standard deviations were less than 1.6% for 10 and 20 mg P L−1 solutions (n = 9). The analytical frequency was 180 h−1. The results obtained using the proposed FIA procedure and those obtained using a standard spectrophotometric procedure agree at the 95% confidence level. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:236–240, 2000
A field-deployable, flow-injection-based instrument for monitoring nitrate in rivers is described. It incorporates a miniature spectrometer that gives full spectral acquisition (200–700 nm) in real time. This allows the dynamic range to be adjusted in the field to meet local requirements by monitoring at different wavelengths. For pristine environments, a linear range of 0–1 mg L−1 NO3-N (r2 = 0.9998, n = 6) and a detection limit of 0.007 mg L1 NO3-N (based on blank plus 3s) were achieved by monitoring at 597 nm. For impacted environments, a linear range of 0–9 mg L−1 NO3-N (r2 = 0.9998, n = 6) was achieved at 510 nm. Conventional peristaltic pumps were replaced by solenoid-operated, self-priming micropumps, and injection of sample was achieved by a series of electronic switching valves. The pulsations of the micropumps were effectively removed by subtracting the response at a nonabsorbing wavelength (444 nm). Instrument control and data acquisition and processing were done within a graphical programming environment. The monitor was successfully deployed for 3 days at the River Frome in Dorset, United Kingdom. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:183–193, 2000
A flow injection system with online sample preparation is proposed for the determination of phosphite in liquid fertilizers by spectrophotometry. After loop-based injection, phosphite is oxidized by an acidic permanganate solution (1.0 10−2 mol L−1 KMnO4 + 1.0 mol L−1 H2SO4) in a heated reactor (50 °C). The phosphate generated is then determined by the molybdenum blue method. Influence of flow rates, temperature, and concentration and order of addition of reagents, sample volume, and reactor configuration for the blue complex formation on recorded signals were investigated. The flow system was applied to phosphite determination in commercial samples of liquid fertilizers. The proposed system handles about 80 samples per hour [0.05–0.40% (w/v) H3PO3; R = 0,9998), consuming about 80 μL sample, 1 mg KMnO4, 25 mg (NH4)6Mo7O24, and 10 mg ascorbic acid per determination. Results are precise [relative standard deviation ≤ 3.5% for 0.1% (w/v) H3PO3, n = 12] and in agreement with those obtained by gravimetry at 95% confidence level. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:286–290, 2000
Monitoring of urinary glucose level is of great interest in health control. As a fast and accurate means to achieve this purpose, a potentiometric glucose biosensor based on SnO2 film was developed. The optimum manufacturing conditions and the functional characteristics of the biosensor were established. The n-type Sb-doped SnO2 semiconductor film properties were characterized using electrochemical impedance spectroscopy. Measurements on urine samples yielded results that are in good agreement with those obtained with the Nylander method and more accurate than those obtained with a test paper. Taking into account that urine samples do not need pretreatment and that by the renewal of the enzyme membrane the stability period of the biosensor may be prolonged over 8 days, it may be used in continuous flux, too. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:291–295, 2000
The next flow system with fully rotary valve (FRV) has been designed and applied for calibration purposes in chemical analysis. In the present case the system was aimed at performing two-component analysis, namely, at preparing the set of two-component standard solutions and using them for calibration and determination of both components in a sample. It has been proven that the FRV, if suitably configured and operated, was capable of using only two initial standards for preparation of eight two-component solutions and furthermore, of composing them in accordance with the incomplete 32 experimental plan. Owing to that, the mathematical models then formulated on the basis of measurement data could serve not only for estimation of the concentrations of both analytes in a sample, but also for evaluation and elimination of the mutual influences between them. It has been experimentally revealed that the system developed allows the calibration procedure to be performed with low consumption of time, work, and reagents, providing reliable analytical results and valuable information about interferences. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:228–235, 2000
Appropriate design of flow-injection (FI) manifold and selection of suitable detectors may provide additional changes in the selectivity of the FI response compared to conventional nonflow measurements. As an example of such systems, based on data from the literature and our own experimental data, the potentiometric detection with different ion-selective electrodes and two different amperometric systems are discussed. Selectivity changes in flow-injection analysis (FIA) systems for ion-selective membrane electrodes depend on relative response to interferences observed in batch measurements. Simultaneous detection of pesticides is shown as an example of an amperometric FIA system with a bilayer lipid membrane working electrode. Simultaneous detection of lactate and ascorbate is shown in an FIA system with amperometric biosensing detection. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:205–215, 2000
This article reviews the use of a wall-jet type flow-through detector for the potentiometric determination of quinine and paraquat ions, respectively, undertaken within our research laboratories. The detector allows the evaluation of the analytical response characteristics of the poly(vinyl chloride)-based membranes to be done in the flow injection analysis mode. Such ion-selective electrode membranes, containing either ion-exchangers or neutral carrier type of electroactive component, in conjunction with appropriate plasticizing solvent, and sometimes other membrane additive as was the case for paraquat selective membranes, can be conveniently applied to the detector assembly. Utilization of the flow-through detector allows studies on the sensing of the antimalarial drug, quinine, and the herbicide, paraquat, to be conducted conveniently. Details of the flow-through detector and its performance when used for the determination of the respective ion of interest under different matrices are described. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:133–137, 2000
Lipoprotein(a) [Lp(a)] is considered an independent risk factor in atherosclerosis and thrombosis. Its measurement in clinical laboratories necessitates the use of reliable methods and a strict control of preanalytical conditions. We studied here the potential interference of hemolysis on a peak rate nephelometric method. Serum samples were spiked with up to 500 μmol/L hemoglobin (Hb), and Lp(a) was measured with a Beckman Array 360 analyzer. Hb supplementation induced a significant decrease of Lp(a) values: −15% and −25% (p < 0.01) for Hb concentrations 200 and 500 μmol/L, respectively. Similar results were obtained when Hb addition was done before and after the manual step of sample predilution (1/5, v/v) in PEG-containing buffer. No significant difference of Hb interference was noticed according to apo(a) phenotypes. Our results indicate that hemolysis may significantly alter Lp(a) values obtained with this method, probably because of the low-dilution rate of samples. Even if this interference is of limited extent, it should be taken into account when interpretating results close to decisional values used for risk assessment. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:23–26, 2000
A robotic workstation for automated organic synthesis was developed. The system consists of a computer, robot, and several devices (reaction device, separation device, dispense device, etc.). The reaction device has four temperature-regulation units, each of which can freely change its set reaction temperature. Since each of the four can handle four reaction containers, 16 reactions under different conditions can be done simultaneously. The range of reaction temperature is from −30°C to 160°C. Reactions beyond the boiling points of solvents are possible by using reflux condensers. The separation processing device automatically performs solution extraction operations based on the detected liquid levels and interface positions. The dispensing device automatically pumps various kinds and amounts of reagents and/or solvents at various speeds into the reaction containers by switching valves through the digital syringe pump. This system can automate all synthesis and analysis process and can perform at least 3000 experiments (3000 containers) per year. Since its completion in 1996, it has conducted over 1500 experiments of various kinds. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:2–11, 2000
A flow-through spectrophotometric sensor for determination of copper based on retention of Cu(I)-1,2 ciclohexanedione thiosemicarbazone complex on C18 bonded phase beads packed in a flow-cell was developed. The method is highly selective for copper; it features a detection limit of 50 ng mL−1 and a linear range from at least 0.1 to 10 μg mL−1. The method is subject to very few interferences and is more sensitive than the batch procedure. The proposed method was applied to the determination of copper in catalysts and alloys. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:241–245, 2000
In this article, we give some information about the computation and the selectivity of DZ descriptors for a set of chemical structures. The relations between the descriptors, autocorrelation components, and Wiener's index are given. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:37–40, 2000
