The Journal of Automatic Chemistry最新文献

There are a number of factors (planning, process optimization, organizational structure, people development and the need to see the total picture) that must be in place for automation to be as effective as possible. This paper discusses these factors and their relationship with automation. It evaluates less obvious areas associated with automation, as well as the more established ones, and discusses the premise that it is the integration of all these aspects that truly offers the biggest opportunities.

A spectrometric method for the determination of L-carnitine has been developed based on the reaction of the 5,5' dithiobis-(2-nitrobenzoic) acid (DTNB) and adapted to a Technicon RA-2000 automatic analyser Química Farmacéutica Bayer, S.A.). The detection limit of the method is 13.2 mumol/l, with a measurement interval ranging from 30 to 320 mumoll1. Imprecision and accuracy are good even at levels close to the detection limit (coeffcient of variation of 5.4% for within-run imprecision for a concentration of 35 mumol/l). A good correlation was observed between the method studied and the radiometric method. The method evaluated has suffcient analytical sensitivity to diagnose carnitine deficiencies. The short time period required for sample processing (30 samples in 40min), the simple methodology and apparatus, the ease of personnel training and the low cost of the reagents make this method a good alternative to the classical radiometric method for evaluating serum L-carnitine in clinical laboratories without radioactive installations.

An automated sensor system for the continuous and in-line measurement of hydrogen peroxide in industrial applications is described. The hydrogen peroxide concentration can be measured over the entire pH range, over a wide concentration range of hydrogen peroxide (10(-3) 70 g/l), from 0 to 70( degrees )C, and with high precision and accuracy (errors less than 1% ). The system consists of a bypass in which the necessary electrodes are positioned and electronically controlled. The sensor is very selective for hydrogen peroxide, easy to instal, and it is stable for at least two months after calibration. The calibration can be done in the process solution during a running process.

This paper describes rapid, simple microwave-assisted leaching/ digestion procedures for total and mercury species determination in sediment samples and biomaterials. An open focused microwave system allowed the sample preparation time to be dramatically reduced to only 24 min when a power of 40-80 W was applied. Quantitative leaching of methylmercury from sediments by HNO(3) solution and complete dissolution of biomaterials by an alkaline solution, such as 25% TMAH solution, were obtained. Methylmercury compounds were kept intact without decomposition or losses by evaporation. Quantitative recoveries of total mercury were achieved with a two-step microwave attack using a combination of HNO(3) and H(2)0(2) solutions as extractant. The whole pretreatment procedure only takes 15 min, which can be further shortened by an automated robust operation with an open focused system. These analytical procedures were validated by the analysis of environmental certified reference materials. The results confirm that the open focused microwave technique is a promising tool for solid sample preparation in analytical and environmental chemistry.

The intensifying pressure on reducing the development time for new pharmaceutical products is resulting in an increasing need for laboratory automation. A key element for the successful implementation of robotics for drug product analysis is the establishment of a reliable process for interaction of the automation team with its various customers, for example development product team and manufacturing group. The reduction of cycle time for product development appears to be resulting in more stability studies to support NDA/MAA filings for several reasons. Key clinical information may not be available before initiation of the stability studies and simultaneous world-wide development may result in an increase in the number of product strength and pack options.

Simultaneous spectrophotometric determination of Mn, Zn and Co was studied by two methods, classical partial least-squares (PLS) and kernel partial least-squares (KPLS), with 2-(5-bromo-2- pyridylazo)-5-diethylaminephenol (5-Br-PADAP) and cetyl pyridinium bromide (CPB). Two programs, SPGRPLS and SPGRKPLS, were designed to perform the calculations. Eight error functions were calculated for deducing the number of factors. Data reductions were performed using principle component analysis. The KPLS method was applied for the rapid determination from a data matrix with many wavelengths and fewer numbers of samples. The relative standard errors of prediction (RSEP) for all components with KPLS and PLS methods were the same (0.0247). Experimental results showed both methods to be successful even where there was severe overlap of spectra.

This paper describes an automatic system which measures the effect of temperature variations on the response of ion-selective electrodes (hysteresis curves). The system is managed by a computer program which plots hysteresis curves following a pre-established temperature cycle, from setting and controlling the temperature of the water-bath, to acquiring the response potentials of up to five electrodes after temperature stabilization.

Electro-active elemental sulphur dissolved in hydrazine hydrate solvent was studied by d.c. polarography, cyclic voltammetry and millicoulometry in sodium acetate, ammonium tartrate and sodium phosphate buffers in an aqueous medium. The method, which uses a mercury electrode, is highly sensitive with less interference than other polarographic methods. The method was extended to the determination of sulphur in pressure rubber tubing. This paper also suggests a mechanism of electrode reaction.