Centrifugal Fast Analyzer Research Articles

Evaluation with the centrifugal fast analyzer of a chemical activation procedure for creatine kinase MB isoenzyme.

The differential activation method for the determination of the "myocardial" isoenzyme of creatine kinase (MB) is based on the computed difference in activity of serum aliquots activated by the combination of dithiothreitol and glutathione (skeletal plus myocardial creatine kinase) and by glutathione alone (skeletal creatine kinase). The unique ability of the Centrifugal Fast Analyzer to perform analyses in parallel is used to precisely measure (CV = 0.1-1.5%) the activity of the two chemically activated aliquots. Statistical considerations concerning the reliability of this difference estimation are discussed with respect to both the precision of the rate measurements and to the relative amount of isoenzyme MB present. Another potential source of error in the analysis of the two differently activated aliquots, namely variation in lag phases, is circumvented by use of a linear-search FOCAL software package. This program searches the data for a linear segment of maximum slope, automatically rejecting those data that appear in lag or depletion regions of the curve representing the progress of the reaction. Correspondence of the results obtained with those of comparison techniques (chromatography and electrophoresis) are discussed.

Enzyme immunoassays with the miniature centrifugal fast analyzer.

We studied the EMIT (Enzyme Multiplied Immunoassay Technique, Syva) procedures for the assay of phenytoin and phenobarbital in serum, adapting them to the miniature Centrifugal Fast Analyzer. For different concentrations of drug, each rate of reaction decreased continuously with time, tending to converge on a single common value. The rate was most affected by the concentration of drug almost immediately after the reagents were mixed, less so thereafter. The antibody evidently is present in sufficient excess to bind all the enzyme-labeled drug ordinarily present, but the antibody-bound enzyme was only 75% inhibited; this helps explain the appreciable residual activity when no drug is present. The reaction course was the same whether the serum and enzyme-labeled drug were added to the antibody sequentially or simultaneously, which suggests that antibody is bound to drug appreciably faster than to enzyme-labeled drug. The reaction rates 15 to 30 s after mixing were used as the measure of the drug concentrations. These results were confirmed by noting the rates at successive 15-s intervals. The analyzer yielded a run-to-run CV of 10% for phenobarbital at 30 mg/liter, and 9% for phenytoin at 15 mg/liter, as compared to the 15% quoted by Syva.

Adaptation of Manual Test Reagents to Centrifugal Fast Analyzer System

Journal Article Adaptation of Manual Test Reagents to Centrifugal Fast Analyzer System Get access Thomas C. Stewart, Ph.D., Thomas C. Stewart, Ph.D. Thomas C. Stewart, Ph.D., is Clinical Chemist and Beverly A. Farrell, M.S., MT(ASCP), is a staff member of the Division of Hospitals, Louisiana Health and Human Resources Division, Earl K. Long Memorial Hospital, Baton Rouge. Search for other works by this author on: Oxford Academic PubMed Google Scholar Beverly A. Farrell, M.S., MT(ASCP) Beverly A. Farrell, M.S., MT(ASCP) Thomas C. Stewart, Ph.D., is Clinical Chemist and Beverly A. Farrell, M.S., MT(ASCP), is a staff member of the Division of Hospitals, Louisiana Health and Human Resources Division, Earl K. Long Memorial Hospital, Baton Rouge. Search for other works by this author on: Oxford Academic PubMed Google Scholar Laboratory Medicine, Volume 7, Issue 10, 1 October 1976, Pages 29–31, https://doi.org/10.1093/labmed/7.10.29 Published: 01 October 1976

Simultaneous Determination of Silica and Phosphate in Water from a Single Experiment Using a Miniature Centrifugal fast Analyzer

Abstract The utility of Centrifugal Fast Analyzers for kinetic analyses of inorganic constituents is discussed and is illustrated for the simultaneous determination of silica and orthophosphate as the unreduced heteropoly acids. Silica is determined by an initial-rate approach, whereas the absorbance intercept is a measure of the orthophosphate content of the sample.

Specific Protein Analysis by LightScatter Measurement with a Miniature Centrifugal Fast Analyzer

Specific Protein Analysis by LightScatter Measurement with a Miniature Centrifugal Fast Analyzer

Development of a Multipurpose Optical System for Use with a Centrifugal Fast Analyzer

A Centrifugal Fast Analyzer is basically a sophisticated photometric measuring device containing a multicuvet rotor as its major component. Several reactions are simultaneously initiated in the rotor, which is then rotated through a stationary optical monitor and the resulting signals acquired and processed by an on-line data system. ?With the miniature version of this analyzer, one has the option of directing the incident optical beam, via a fiber optical bundle, into the cuvets of the spinning rotor in either a 90 degrees or a 180 degrees orientation relative to the analyzer's photodetector. tthe combination of newly designed rotors and a flexible optical system having multiple configurations has provided a versatile system in which one can measure the transmittance, fluorescence, chemiluminescence, or light-scattering (either turbidimetrically or nephelometrically) properties of the ensuing reaction species, all with a single analyzer. This flexibility in choosing the optical mode in which a particular set of reactions is to be monitored provides the analyst with a powerful and versatile analytical tool for developing new methods for use in various clinical laboratory applications, including chemistry, toxicology, immunology, and hematology.

Coagulation-Time Determination with Automatic Multivariable Analysis, by Use of a Miniature Centrifugal Fast Analyzer

Use of a miniature Centrifugal Fast Analyzer for the parallel photometric monitoring of the coagulation process is shown to have a number of advantages. These include a choice of optical modes, virtually simultaneous initiation and observation of the coagulation process for a number of patient-plasma samples and an on-board control sample, small sample and reagent volume requirements, and automatic determination of a number of diagnostically useful variables (including relative fibrinogen content) from the data recorded in a single run. Also, the system is shown to give results that correlate well with those obtained by conventional techniques for determination of prothrombin time.

Rapid determination of chromium in natural waters by chemiluminescence with a centrifugal fast analyzer

The centrifugal fast analyzer was adapted for luminescence measurements by designing an improved transfer disk which mixes solutions more efficiently and by reprogramming the dedicated computer for rapid data acquisition. The modified analyzer system was applied to the chemiluminescent determination of chromium( III) and, after reduction, chromium(VI), by catalysis of the luminol-peroxide reaction in basic medium. From 50 to 600 p.p.b. of chromium in water samples were determined with a relative standard deviation of 1–2%. Sensitivity can be increased if necessary. The method is very rapid—as many as 11 samples can be analyzed in 2.5 s—and only a small sample, 0.3 ml, is required. Since this. method is selective for uncomplexed chromium(III) ions, comparison of results with analyses for total chromium and chromium(VI) by other methods provides information concerning the chromium species present in a sample and the presence or absence of complexing agents.

Specific Protein Analysis by Light-Scatter Measurement with a Miniature Centrifugal Fast Analyzer

Abstract A miniature Centrifugal Fast Analyzer has been modified for fluorescence and light-scatter measurements by using several rotors developed for this purpose. The modified system has been used to evaluate the feasibility of adapting specific protein analyses, such as IgG, IgA, IgM, C'3 complement component, and α-1-antitrypsin, to the Centrifugal Fast Analyzer. A study of reaction conditions has revealed that the addition of polyethylene glycol 6000 (Carbowax) to the dilution medium increases the rate of reaction and allows apparent equilibrium to be achieved in less than 60 s. Furthermore, scatter intensity is enhanced. This system can be used to make rapid immunoglobulin measurements with only microliter volumes of antibody (2-7 µl), without the need of sample blanks. Determination of antigen excess by a method that involves dynamic injection of antibody is also discussed.

Optimization and Analytical Applications of the Technique of Dynamic Introduction of Liquids into Centrifugal Analyzers

Abstract The technique of dynamically introducing a measured volume of liquid into the spinning rotor of a miniature Centrifugal Fast Analyzer where it is subsequently apportioned into equal aliquots [C. D. Scott and J. C. Mailen, Clin. Chem. 18, 749 (1972)] has been further developed and improved. Several important structural and operational factors have been identified and investigated, including rotor design and geometry, rotor speed, injection volume and rate, and probe diameter. To determine the effect of these factors on the precision and accuracy with which a liquid may be dynamically introduced and apportioned, we developed a dye-dilution procedure. These studies demonstrate that liquid volumes ranging from 10 to 50 µl per cuvet can be dynamically loaded with an accuracy and precision (expressed as standard deviation) of 1 to 2% and 0.5 to 1.1 µl per cuvet, respectively. Several analytical applications of this technique have been investigated: (a) measurement of true sample-blank absorbance before dynamic reagent introduction, (b) sequential reagent addition, (c) correlation studies involving discrete versus dynamic loading of reagent, and (d) reconstitution of lyophilized reagents.

A Small Portable Centrifugal Fast Analyzer System

Abstract The recent development of minature fast analyzer systems based on the GeMSAEC principle, coupled with the possibility of direct introduction of unprocessed liquid samples, has been further extended to include a very small analytical system that is inexpensive, battery-operated, and portable. The basic analyzer is included in and on a cabinet, about 10 x 10 x 10 cm, and a coupled data-processor records analytical data in absorbance units and in arbitrary fluorescence units. The system is compatible with up to seven simultaneous colorimetric or fluorometric assays on physiologic fluids. The dynamic mode of sample loading is used, and the system is compatible with the introduction of unprocessed whole blood. End-point or rate analysis is possible, and the coefficient of variation obtained in multichemistry tests on a single serum sample introduced dynamically is comparable to that obtained with larger Centrifugal Fast Analyzer systems.

Blood Grouping with a Miniature Centrifugal Fast Analyzer

Abstract The Centrifugal Fast Analyzer was used to develop a semiautomated, computerized blood-grouping system. A miniaturized version of the Analyzer was used for the development because, essentially, it enables one to automate "test-tube" grouping procedures. The blood-grouping system is discussed in terms of adaptation of blood-grouping procedures; types of instrumentation used for grouping, cell washing, and Coombs testing; parametric optimization of hemagglutination reactions; subgrouping of A and AB; reverse typing; small-scale blood-grouping evaluation of our approach; and computerization of blood grouping. The data reported here indicate that the system reliably provides accurate results.

Serum Alkaline Phosphatase: Total Activity and Isoenzyme Determinations Made by Use of the Centrifugal Fast Analyzer

Abstract We present a kinetic method in which the centrifugal analyzer is used to determine total alkaline phosphatase activity and to measure the isoenzymes in bone, liver, and the L-phenylalanine-sensitive fraction (intestine, tumor, and placenta). Measurements were made at 30°C in diethanolamine buffer, with p-nitrophenylphosphate as substrate. The alkaline phosphatase isoenzymes were separated and measured by selective chemical inhibition with 10 mmol/liter L-phenylalanine and 3.3 mol urea per liter. Analyses were performed on sera of a group of healthy pediatric and young adult volunteers and, in addition, on sera from patients with clinically documented osteoblastic disorders and hepatobiliary diseases. The precision and accuracy of the centrifugal analyzer were evaluated, as was the suitability of the instrument for routine clinical laboratory use.