Laboratory Robotics and Automation最新文献

The design, development, and testing of a flow-injection analysis (FIA) manifold for the simultaneous determination of two species in water samples are reported. Fluoride is determined potentiometrically, and, following on-line sample dilution and treatment, amperometric analysis of phenolics is performed. The combination FIA system is a rapid, low-cost, highly reproducible method that uses small sample volumes and could be used to provide on-site near-real-time measurements. © 1999 John Wiley & Sons, Inc. Lab Robotics and Automation 11: 105–109, 1999

An automatic system for the stepwise treatment of solid samples is described. The system is controlled by a PC computer that is connected to a burette equipped with a three-way valve, to a peristaltic pump, and to a robot arm through two serial interfaces. In a cycle, the burette introduces a solvent volume in the sample cell, sonication is applied, and, after a fixed time, the pump carries the solvent to the vial selected by the robot arm. Measurements can be performed both in-line and off-line by analyzing the vial series. The program was written in Visual Basic 3. Lixiviation rates of several cations from the lichen Ramalina farinacea were measured by capillary zone electrophoresis using the vial series obtained in several experimental conditions. The automatic system gave better reproducibility than the manual procedure. Initial lixiviation rates were higher in the presence of ultrasounds. © 1999 John Wiley & Sons, Inc. Lab Robotics and Automation 11: 121–126, 1999

A conventional instrumentation based on batch procedure and a continuous flow analyzer for monitoring chemiluminescence and bioluminescence reactions are described. A possible development for measuring electrogenerated chemiluminescence would be the incorporation of the electrochemical flow cell in conjunction with flow injection analysis. The advantages of continuous flow analyzer for monitoring these reactions and the detector design are also discussed. © 1999 John Wiley & Sons, Inc. Lab Robotics and Automation 11: 91–96, 1999

Two major approaches exist for devising gait control for a legged machine: (1) finding a sequence of leg and body movements of a robot on the basis of kinematic and possibly dynamic considerations assuming all foot placements are valid and (2) selecting leg and body movements first on the basis of feasibility of foot placements (because the underlying terrain might render impossible certain foot placements) and then accepting those that also satisfy kinematic and possibly dynamic constraints. Consider now the problem of a legged robot pursuing a quarry. With the first approach, the robot will be limited to operating over a relatively flat terrain; over such a terrain, it might be able to synthesize a sequence of precomputed straight-line and turning gaits in order to match as closely as possible to the trajectory of the quarry. If the terrain is uneven, however, the robot will have no recourse but to take the second approach, even though it is computationally more demanding. The work done so far in the second approach is limited either by the constraint that the overall direction of ambulation of the robot is known in advance or by the constraint that the foot placements are limited to the points of a grid superimposed on the topographic map of the terrain. This article presents how a free gait can be generated for following a quarry without invoking such constraints. The robot attempts to adapt constantly its direction of ambulation so that at each instant the quarry is pursued by the shortest path (although there is no guarantee that the path actually traversed by the robot is globally optimal in any sense). The directions generated by this “shortest path pursuit” prune away large segments of the search space for the discovery of appropriate foot placements. Simulated and experimental results are presented to validate the proposed gait control method. © 1999 John Wiley & Sons, Inc. Lab Robotics and Automation 11: 71–81, 1999

The present article reviews the main progress in automation of Mössbauer spectroscopy data analysis by using genetic algorithms, fuzzy logic, and artificial neural networks. Several tests were carried out, and the results are presented and discussed. © 1999 John Wiley & Sons, Inc. Lab Robotics and Automation 11: 3–23, 1999

This article describes the continuous production of glycine by catalytic ammonolysis of monochloroacetic acid in an aqueous medium. The synthesis and crystallization of glycine are carried out in a battery of three stirred double-jacketed reactors while temperature and pH values are controlled. The results of the kinetic study allow one to calculate the residence time in each tank for a desired conversion ratio and are first checked with the setup. Then, some parameters (concentration of reagents, regulation of pH, residence time, catalyst) are modified to improve the final yield in crystallized glycine. The best yield resulting from a flow process (96.6%) is better than that resulting from a batch process (93%) and is obtained in the following conditions: the first step is performed at 75°C and pH 5.4 with a 10 mol L−1 monochloroacetic acid solution and a 17 mol L−1 ammonia aqueous one with a 0.2 molar ratio of hexamethylenetetramine; the second step is carried out at 75°C and pH 8.0; the optimal residence times are respectively 1 and 4 hours. Replacement of hexamethylenetetramine by formaldehyde can also be considered even if the yield is slightly lower. © 1999 John Wiley & Sons, Inc. Lab Robotics and Automation 11: 29–35, 1999

A flow-injection (FI) spectrophotometric procedure is proposed for the determination of vitamin B1 (thiamine hydrochloride) in multivitamin preparations. Powdered sample, containing from 25 to 100 mg of multivitamin preparations, was previous dissolved in 0.1 mol L⁻¹ hydrochloric acid, and a volume of 250 μL was injected directly into a carrier stream of 0.10% (w/v) potassium hexacyanoferrate(III) in 0.5 mol L⁻¹ sodium hydroxide at a flow rate of 2.46 mL min⁻¹ an FI system. The thiochrome produced in the oxidation of thiamine hydrochloride by potassium hexacyanoferrate(III) in alkaline solution was directly measured at 369 nm. Potassium hexacyanoferrate(III) in this concentration did not cause any interference.

Vitamin B₁ was determined in three multivitamin preparations in the concentration range from 2.5 to 50.0 mg L⁻¹ (calibration graph: A = −0.0132 + 0.0134 C, r = 0.9990, where A is the absorbance and C is the vitamin B₁ concentration in mg L⁻¹). Sucrose, glucose, fructose, lactose, citric acid, starch, vitamin B₂, and vitamin B₆ do not interfere, even in concentrations five times higher than vitamin B₁. Only vitamin B₁₂ causes interference, but this vitamin is not present in the multivitamin preparations used in this work. The detection limit was 1.0 mg L⁻¹, and the recovery of vitamin B₁ from three samples ranged from 97.5 to 105.0. The sampling rate was 41 h⁻¹ and RSDs were less than 1% for solutions containing 10.0 and 30.0 mg L⁻¹ vitamin B₁ (n = 10). The results obtained for the determination of vitamin B₁ in commercial preparations are in good agreement with those obtained by differential pulse polarography (r = 0.9999) and also with the label values (r = 0.9998). © 1999 John Wiley & Sons, Inc. Lab Robotics and Automation 11: 45–50, 1999

This article reports an automated sample preparation for determination of total siloxanes in shampoo products using an inductively coupled plasma (ICP). A fully automated robotics system requires only setting blank sample tubes on the racks and putting products into these tubes manually. Robot preparation gives us higher efficiency in extraction and lower RSD than current manual preparation.

The analytical data sets demonstrate accuracy, precision, and reproducibility of the sample preparation. Linearity, accuracy, and precision ensure the validity of the robotics method. The method has a linearity working range from 0 to 500 ppm (correlation coefficient, R = 0.9999). The method gives the sufficient recoveries, R = 101 ± 1%. Relative standard deviation (RSD) is 0.42%. © 1999 John Wiley & Sons, Inc. Lab Robotics and Automation 11: 25–28, 1999

A flow-injection system for iodide determination has been developed based on the Sandell and Kolthoff reaction in which iodide catalyses the reaction of Ce(IV) and As(III). The decrease in Ce(IV) concentration measured colorimetrically in the range 410–430 nm, after a fixed time interval, is thus dependent on the iodide concentration. The method is simple and sensitive to very low concentrations of iodide. The detection limit is 0.8 μg I− L−1 (S/N = 3). The calibration graph was found to be linear over a range of 0–7 μg L−1. The effects of some interferents, including halides and others that are found in urine and milk samples (glucose, ascorbic acid, thiocyanate ion, bicarbonate ion and calcium ion), were studied. The presence of fluoride ion, thiocyanate ion, or oxidizable organic molecules caused serious positive errors. Sulfate ion was the only interferent examined that caused a negative error, but the effect of sulfate can be ignored when its concentration is less than 10⁵ mg L−1. © 1999 John Wiley & Sons, Inc. Lab Robotics and Automation 11: 37–44, 1999