Analyzer centrifugal

Another automated approach to kinetic analyses is the centrifugal analyzer, a partial cross section of which is shown in Figure 13.9. In this technique the sample and reagents are placed in separate wells oriented radially around a circular transfer disk attached to the rotor of a centrifuge. As the centrifuge spins, the... 

Flow injection analysis (FIA) was developed in the mid-1970s as a highly efficient technique for the automated analyses of samples. °> Unlike the centrifugal analyzer described earlier in this chapter, in which samples are simultaneously analyzed in batches of limited size, FIA allows for the rapid, sequential analysis of an unlimited number of samples. FIA is one member of a class of techniques called continuous-flow analyzers, in which samples are introduced sequentially at regular intervals into a liquid carrier stream that transports the samples to the detector. ... 

At present, several of the instruments which are being utilized for enzyme analysis, such as the centrifugal analyzers (15), have been measuring samples of the order of 5 pi. 

Figure I. Front view of the miniature centrifugal analyzer. The mechanical, analytical, and optico-electronic components are in one compact unit. Digital data reduction is in another unit, not shown, Courtesy of Dr, Carl A, Burtis, of the former Oak Ridge National Laboratory),...

Harvey, M. Measurement of erythocytes glucose-6-phosphate dehydrogenase activity with a centrifugal analyzer. Clin. Chem. (1975), 134-138. 

An area worthy of study is the development of systems of increasing sample throughput beyond the single column operation. Scott has introduced a prototype multicolumn system based on the centrifugal analyzer principle (53). In this set-up a series of LC colimns is rotated on a disc, with sample delivery at the center of the disc and elution and spectrophotometric analysis on the outside. He has suggested using affinity columns for rapid serum protein analysis by this approach. Of course, other principles, such as segmented flow, could be envisioned in an automated LC system as well. Undoubtedly, we can expect to see the availability of such systems in the next few years. 

Percent solid settled In tests where adsorption and flocculation were determined simultaneously, the 200 ml sample was allowed to settle for 30 seconds and then 100 ml of the supernatant was removed using a suction device and after centrifugation analyzed for residual polymer concentration. The minimum level of detection was at 0.5 to 1 ppm and the reproducibility of the adsorption measurements was 2-3%. The settled 100 ml portion was analyzed for solid content. Flocculation due to polymer addition is measured by noting % solid settled as a function of polymer concentration. 

Brunk, S.D. Hadjiioannou, T.P. Hadjiiannou, S.I. Malmstadt, H.V. Adaptation of emit technique for serum phenobarbital and diphenylhydantoin assays to miniature centrifugal analyzer. Clin. Chem. 1976, 22, 905-907. 

Some of the centrifuged solids obtained from the equilibrium adsorption studies were immediately subjected to consecutive desorption analyses. The liquid centrifugate was carefully drained from the test tubes and replaced with 25 ml of organic-free water. The tubes were then sealed with the teflon-lined screw tops and agitated for 24 hours. The tubes were then withdrawn, centrifugated, and the centrifugate analyzed as before. This procedure was performed several more times. Representative results from these... 

E662 Moriguchi, J., Senn, C. and Freier, E. (1990). Comparison of Kodak Ektachem 700XR and micro centrifugal analyzer for analysis of cerebrospinal fluid lactate. Clin. Chem. 36, 1199, Abstr. 1154. 

Hills LP, Tiffany TO. Comparison of turbidimetric and light scattering measurements of immunoglobuUns by use of a centrifugal analyzer with absorbance and fluorescence hght scattering optics. Clin Chem 1980 26 1459-66. 

Centrifugal analyzers were invented and developed in the early 1970s by Norman Anderson and his colleagues at the Oak Ridge National Laboratory with funding provided by the U.S. Atomic Energy Commission, National Institute of... 

Bertrand A, Buret J. A one-step determination of serum 5 -nucleotidase using a centrifugal analyzer. Clin Chim Acta 1982 119 275-84. 

Ludvigsen CW, Thurn JR, Pierpont GL, Eckfeldt JH. Kinetic enzymic assay for D(-)-lactate, with use of a centrifugal analyzer. Clin Chem 1983 29 1823-5. 

Lutz RA, Fluckiger J. Kinetic determination of glucose with the GEMSAEC (ENI) centrifugal analyzer by the glucose dehydrogenase reaction, and comparison with two commonly used procedures. Cfin Chem 1975 21 1372-7. 

Law WT, Ertingshausen G. A novel reagent and method for determination of chloride in serum with a centrifugal analyzer. Clin Chem 1980 26 1874-7. 

Barbour HM, Davidson W. Studies on measurement of plasma magnesium application of magon dye method to the Monarch centrifugal analyzer. Clin Chem 1988 34 2103-5. 

Tsang WM, Howell Mf Miller AL. A simple enzymic method for the measurement of magnesium in serum and urine on a centrifugal analyzer. Ann Chn Biochem 1988 25 162-8. 

The development and application of centrifugal analyzers, a major advance in automated enzyme assays, is described by Tiffany et al. (5). This device was the first to use computerized process control and data reduction. There are many reports in the literature that evaluate or compare specific instruments. Some... 

Creatine kinase Medium basic anion exchanger chromatography Anion exchange chromatography and centrifugal analyzer Anion exchange chromatography and evaluation of all separation methods Klein et al. [352] Elkins [353] Morin [354]... 

Dooley, J. R, and L. Racich. 1980. A new kinetic determination of serum 5 -nucleotidase activity with modifications for a centrifugal analyzer. Clinical Chemistry 26 1291-1297. 

Brun, E., F. Lingaas, and H. J. Larsen. 1989. Turbidimetric measurement of immunoglobulin G in serum using an automatic centrifugal analyzer. Research in Veterinary Science 46 168-171. 

The term parallel analysis has been coined in connection with centrifugal analyzers [4.3], in which assays are executed by means of spectro-photometric measurements on a number of samples that are simultaneously mixed in individual cavities of a rotating disk and scanned by a single beam of light (Chapter 1). 

Figure 24.13. Cross-section of sample disc and centrifugal-analyzer section of parallel-fast analyzer. From R. C. Coleman, W. D. Schultz,...

The first attempts for automation of solution handling which made up the bulk of labour in an analytical laboratory was simply mechanizing and simulating the traditional batch operations under a conveyer-belt concept. This was an approach which proved to be cost effective and efficient enough to gain widespread acceptance. Batch analyzers which were more successful include the Dupont sample bag" analyzers and the parallel centrifugal analyzers. They are, however, expensive devices, and their use is rather limited, moreover, they are not designed to perform separations. 

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