Automated Determination of Arsenic,Selenium, Antimony,Bismuth and Tin by Atomic Absorption Utilizing Sodium Borohydride Reduction

Abstract

An automated system for the determination of arsenic, selenium, antimony, bismuth and tin is described. These elements and their compounds are reduced with sodium borohydride to the corresponding hydride. Sensitivity of the automated system is comparable and in most cases better than the manual technique. The automated method was found superior to the manual with respect to reproducibility and ease of operation.     

Analysis of Bilirubin (Total or “Direct”) with an Automated Michaelsson Method on the Dsa-560 Autoanalyzera

Abstract

A method for the determination of Bilirubin, total or “direct”, is presented. It is a fully automated version of the Michaels son method, comprising the introduction of the sample at the beginning and at the end of the reaction sequence. Reference values are proposed based on the Gaussiam distributions of the square roots of values measured in blood donors, 99 men and 97 women.     

An Automated Spectrophotometric Flow Injection Assay of Alkaline Phosphatase

Abstract

Assay of alkaline phosphatase using an automated flow injection manifold is described. The detector used is a spectrophotometer. The measurement is based on the rate of formation of p-nitrophenol at 405 nm, from the substrate p-nitropheny1 phosphate. The linear range, precision and accuracy of the technique for the assay of the enzyme is given. The advantages of the approach to assay of plasma enzymes are also discussed.     

Comments on “A Simple Gas Chromatograph Sample Introduction System”

Abstract

The utilization of a simple gas chromatograph sample introduction system is expanded from research laboratory to industrial laboratory by using a more readily automated 6-port valve system.     

An Evaluation of Eluent Recycling and Column Life for HPLC Analysis of Carbohydrates

Abstract

The length of service of amine modified silica columns for the automated analysis of carbohydrates in food and beverages typically exceeds 500 sample injections. Excessive accumulation of carbohydrate in the recirculated eluent results in a gradual decrease in peak height. Detector response is independent of injection volume over the range of 1–50 μl. These results suggest critical parameters for use in automated carbohydrate analysis systems.     

Evaluation of System Errors in TLC-Densitometry when using the Streaking Technique

Abstract

The errors that contribute to the total variance of the automated streaking technique are examined. These results are compared with computer optimized and zig-zag scanning approaches. The error due to inhomogeneous sample distribution is shown to be the most important.     

Crude Oil Hydrocarbon Group Separation Quantitation

Abstract

The petroleum industry like most other industrial segments are continuously developing new and sophisticated techniques of analysis and at the same time are working to automated routine techniques. In the petroleum industry, the source of supply has generally become less stable and economics has dictated new thinking, both in processing and in the analysis of composition to support these new trends. In addition, this industry is faced with having a new raw material, shale oil, and coal liquids, in the near future.     

Observations on Sampling Control Sera: Distributions of Chemistry Quality Control Values

Abstract

Data, obtained in quality control programs in automated clinical chemistry systems are often not normally distributed. Falsely assuming that the data is Gaussian produces errors in classifying patients, and in statistical inferences drawn from parametric tests.     

The Use of an Automated Device in the Direct Simultaneous Determination of Heavy Metals in Commercial Coca Cola By DPASV

Abstract

The performance of a polarographic analyser equipped with a long-lasting, sessile-drop mercury electrode is described in the direct, simultaneous determination of heavy metals (cadmium, copper and lead) in some Coca Cola samples (drawn from commercial bottles or tins). The determinations were performed by the differential pulse anodic stripping voltammetric technique using a programmed fully automated sequence (i.e., deposition-stripping-recording). The results obtained (1-3, 6-25 and 1.5-3.3 ppb for cadmium, copper and lead, respectively) as well as those previously obtained in the stripping analysis of some sea-waters and mineral-waters samples suggest that the proposed automated device ensures sufficient sensitivity and accuracy to be employed in the DPASV determination of toxic metals (at trace and subtrace levels) in natural waters and beverages.     

A High Performance Liquid Chromatography Method for the Determination of Ranitidine in Plasma

Abstract

Ranitidine hydrochloride is a highly potent H₂ receptor antagonist of value in the treatment of peptic ulceration. A method is described for the determination of ranitidine in biological fluids. The drug is extracted from plasma prior to determination by reverse phase high performance liquid chromatography. The method is sensitive enough to determine 10ng ranitidine per ml in plasma. The h.p.l.c. method has been automated so that analysis can be carried out without attention over a 24 hour period. The automated h.p.l.c. method has been used for studying the pharmacokinetics of oral and intravenous doses of ranitidine hydrochloride administered to man.     

Determination of Ethinylestradiol and Norethindrone in a Single Specimen of Plasma by Automated High-Performance Liquid Chromatography and Subsequent Radioimmunoassay

Abstract

A method is described for the specific determination of ethinylestradiol and norethindrone in the same specimen of plasma at concentrations of 20 and 50 pg/ml, respectively. The method is based on fully automated high-performance liquid chromatography for separation of the analytes form one another and from coextracted extraneous components and on radioimmunoassay using antisera of high specificity for the quantification. Validation of the method included demonstration of low procedural blanks, recoverability of added hormones and low intra-assay and inter-assay variability.     

Analysis of Cyanide in Blood by Headspace-Isotope-Dilution-GC-MS

Abstract

An uncomplicated, rapid, automated procedure for the analysis of low cyanide concentrations in whole blood is reported. The analysis was performed by headspace gas chromatography and mass spectrometry in the (¹H¹²C¹⁴N) and m/z 29 (¹H¹³C¹⁵N). Carryover from cyanide adsorption onto the surface of the needle was prevented by developing a new method that enabled automated flushing of the needle in between each cyanide analysis. Results were compared of ordinary calibrations and those of isotope dilutions. The total time of analysis was 18 min for a single cyanide analysis.     

The Analysis of Sulphonamide Drug Residues in Pork Muscle using Automated Dialysis

ABSTRACT

The aim of this study was to assess the suitability of automated dialysis, using a commercial system, for the analysis of sulphonamides in porcine tissue. The system involves automated dialysis, followed by trace enrichment of the dialysate prior to HPLC determination. The procedure was applied to the analysis of nine sulphonamide drug residues using reversed phase HPLC as the method of determination. Muscle samples were blended in saline, centrifuged and the supernatant was filtered before dialysis for an optimised time of 11 min. The resulting dialysate was concentrated on a reversed phase trace enrichment cartridge prior to HPLC analysis with UV detection at 280 nm. The developed method was evaluated by carrying out intra- and inter-assays on fortified porcine muscle. Mean recoveries, evaluated from the inter-assay study, were 80% or higher for the nine sulphonamides studied and the limit of determination for the method was 40 ng g^?1.     

Automated Determination of Ammonia in Natural Freshwaters Using Salicylate-Hexacyanoferrate-Dichloroisocyanurate System

Abstract

An automated method for the determination of ammonia in natural freshwaters was developed with the use of salicylate-hexacyanoferrate-dichloroisocyanurate system. Sodium salicylate is easy to handle and does not produce o-chlorophenol. The use of sodium dichloroisocyanurate as a chlorine donater excludes frequent standarization of chlorine content in sodium hypochlorite solution. Sensitivity in the present method is comparable with that in manual phenol method. The present study suggests that automated salicylate and phenol methods with the need of heating of more than 50°C may not determine the real concentration of ammonia due to the release of ammonia from free amino acids in natural waters.     

Automated Determination of Urinary Polyamines

Abstract

A system for the determination of urinary polyamines by ion exchange chromatography with fluorescence detection is presented. It provides a sensitive and specific assay of putrescine, cadaverine, spermidine and spermine in urine hydrolyzates. An internal standard is used, which makes the automated determination of series of samples easy.     

Automated Extraction of Drugs from Biological Fluids

Abstract

An automated continuous flow liquid-liquid extraction procedure is described for the separation of the H₂-antagonist loxtidine from plasma samples containing two metabolites which interfere in the radioimmunoassay of the drug. The extraction of the bronchodilator salbutamol was studied using the DuPont Prep I automated liquid solid extraction apparatus, with a 12 cartridge capacity, and a vacuum extraction box designed in this laboratory to hold 30 Sep-pak C-18 (Waters Associates) cartridges. Twenty-four plasma samples per hour can be automatically processed with the Prep I. Although the vacuum box is not fully automated 45 plasma samples per hour can be processed. The Prep I can only be used with DuPont XAD, strong cation and anion exchange cartridges. Cartridges containing alumina, silica, floril, cation and anion exchange resins and reverse phase packings can all be used with the vacuum extraction box. The latter costs only a fraction of the Prep I and therefore each analyst can have his own unit.     

An Automated Method for the Determination of Arsenic and Antimony

Abstract

An automated method for determining arsenic and antimony by atomic absorption spectrophotometry based on the evolution of the corresponding hydride by sodium borohydride is reported. This method is rapid and sensitive, and is most suitable for the routine monitoring of the arsenic and antimony levels in surface and ground water, as well as in polluted water.     

The Use of the PREPTM System for Handling of Body Fluids

Abstract

The Du Pont PREP^TM automated sample processor is a centrifugally based, microprocessor controlled instrument that was designed for extraction of samples from biological fluids. Extraction takes place in cartridges containing either organic resins or bonded silica packings as extraction sorbants. This paper will discuss the application of several lipophilic and ion exchange sorbants to the extraction of biological samples from body fluids. The advantages of these different types of sorbants will be compared and their performance with automated sample preparation will be shown. A variety of applications including the extraction of benzodiazepine, barbiturate, aminoglycoside and anticonvulsant drugs and their metabolites from serum, urine, and tissue homogenates will be discussed.     

Determination of Bismuth in Geological Materials by Flow Injection Hydride Generation Atomic Absorption Spectrometry

Abstract

Flow injection analysis (FIA) has been applied to sample introduction in conjunction with automated hydride generation and AAS techniques for the determination of Bi in rock samples. The powdered rock sample is digested with a mixture of hydrofluoric, perchloric, and nitric acids. The evolved hydride is carried through to a heated quartz tube by a stream of argon, and the atomic absorption of Bi is measured at 223.2 nm.

Thiosemicarbazide and 1,10 - phenanthroline are used as masking agents to control interferences from Cu and Ni. The method permits the accurate determination of Bi in geological materials at levels as low as 10 ppb with an analysis rate of more than 50 digested samples per hour. Bi values on 13 international geological reference samples are reported.     

Trace-Level Determination of Phenol by Liquid Chromatography with On-Line Precolumn Technology and Fluorescence Detection

Abstract

A strongly basic anion-exchange resin is used for the trace enrichment and automated sample handling of phenol, with subsequent determination by reversed-phase liquid chromatography with fluorescence detection. Because of the presence of high concentrations of ionic compounds in the water samples tested, phenol is first trapped on a relatively long precolumn filled with a highly hydrophobic packing material; during this step, (in) organic anions which are not retained, are flushed to waste. In the next step, phenol is desorbed from this column at high pH and sorbed in a small zone (“peak compression”) on a short precolumn containing the anion exchanger.

In the analysis of tap and river water samples, the detection limit was found to be 10ppt (1:10¹¹).