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The influence of operating conditions on permeate flux was investigated using organic ultrafiltration membranes to treat a synthetic cutting-oil emulsion containing 0.05 to 0.8 wt. % oil. A commercial cutting oil, Alba-Kool, and four organic ultrafiltration membranes, two made of polysulfone (PM10 and PM30) and the other two of regenerated cellulose (YM10 and YM30), with cut-off sizes of 10 000 or 30 000 Dalton, were used. All experiments were performed in a commercially available stirred ultrafiltration cell. Within the range of operating conditions studied, it was found that the highest fluxes were obtained at the following conditions: crossflow velocity (rotation speed) of 375 rpm, temperature of 40 °C and transmembrane pressure of 0.1–0.15 MPa. Oil rejections between 99 and 99.9% were obtained. Complete membrane regeneration was achieved with a 2 vol. % aqueous solution of a commercial cleaning agent (Derquim+, Panreac). [ABSTRACT FROM AUTHOR]

Methods are discussed for linear calibration with an optimized number of data without loosing effective statistical information. Homoscedasticity is confirmed from, measurements at both limits of the chosen working range. The number of data used is given by the F-test borders. To confirm linearity a third series of measurements is taken near the mean of the working range and uniformity in sensitivity in both resulting parts is proven by t-statistics. If linearity is confirmed only data at the borders of the working range are taken as deducted from error propagation. If it is possible to recalibrate, this way is confirmed by means of the prediction interval. Furthermore, a method is discussed for finding out stochastic independence of data and systematic errors caused by memory effects. [ABSTRACT FROM AUTHOR]

For normalization of spectra in spectral libraries in UV/VIS range the maximum of absorbance, the area under the spectrum or a linear regression technique may be used. Using the error propagation law the best method should be the linear regression followed by area normalization. In practical work the area normalization has no advantages compared to a modified point normalization, where the mean of the maximum and the two next data points are taken. Therefore, in an automated comparison of UV spectra the modified point normalization is used for searching for similar spectra. The final comparison is done after linear regression normalization. This has advantages in calculation of error propagation and significance levels of two spectra. The reference spectrum is used as independent, the spectrum of the sample as dependent variable. [ABSTRACT FROM AUTHOR]

For the identification of UV spectra only such methods will be successful that incorporate all data of the whole spectrum because there is only a small content of information in UV spectroscopy. Numerical values based on integrated subsets of data are efficient for searching similar spectra. For identification three algorithms are described, the difference of two spectra after special normalization, the function of cross correlation and the rank of the two-row matrix containing the spectra of reference and sample. Difference and rank analysis have the advantage of taking the noise as precision of the system and using this as statistical defined limit for identification. [ABSTRACT FROM AUTHOR]

Calibration of ion-sensitive electrodes using nonlinear regression analysis is combined with an increase of the working range to lower concentrations. It is possible to have statistically reliable results lower than the so-called limit of determination according to IUPAC. From these items the critical level, the limit of detection and the limit of determination are derived by the calibration function, its inverse (the function of analysis) and the confidence interval. The limit of detection is defined by the smallest detectable signal and the calibration function. The limit of determination is defined by the smallest concentration of an analysis that will be statistically significant with a preset probability of error differentiated from the concentration zero and the blind value of the potentiometric measurement. The limit of determination is therefore the smallest concentration of analysis that may be quantitatively determined. [ABSTRACT FROM AUTHOR]

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Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Archives of Toxicology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Contrary to IR spectra there are only very few or no maxima in most UV spectra. Therefore library search based on peak tables will not be successful. The use of derivatives seems insufficient for there are too less data points for numerical derivatives and in case of trace analysis the signal-to-noise ratio is too bad. Integral numerical values are proposed as mean absorbance in selected wavelength ranges (200-400, 200-300, 200-260 nm) as characteristics for information ranges in the wavelength domaine. On the other hand, the absorbance domaine is characterized by the cross correlation of the spectrum in the same wavelength ranges. These numerical values will differentiate also very similar spectra as carbromal, ephedrin, pethidin, lidocain and atropin, showing only end absorptions up to about 240 nm. [ABSTRACT FROM AUTHOR]

The straight forward determination of concentrations by means of ion-sensitive electrodes is based on calibration procedures. In the case that the working range is within Nernstian response linear regression with ordinary least square calculation is sufficient. Caused by blanks there are deviations from linearity and calibration has to be done by a non-linear regression technique. Confidence intervals are discussed for both methods of calibration, for the calibration function as well as for the inverse function from the viewpoint of statistics. Furtheron, the expected relative error in the analytical result is taken into consideration as a very useful tool of comparing both methods. The influences of data distances and number of data are discussed. In many cases non-linear calibration has advantages compared to linear calibration eliminating the influence of a blank value. The possible working range is extended even below the socalled blank value. [ABSTRACT FROM AUTHOR]

This paper describes a reliable working station for the in line-process control in chemical plants. Essential parts of the equipment (pump, column) are in duplicates and may be combined by computer control in different lines. One pump and column is in working position, the other is held in ready to work position by conditioning. While one column is in working position, the system is able to calibrate the other column and to switch to this column in the case of breakdown of the other column. By means of chromatographic data (as retention time, peak height of standards, data of separation) the working column is under control and the switching to the other column is down before a real breakdown. The status of the detector is followed by number and distance in time of the necessary auto-zero operations and by the noise of the lamp. [ABSTRACT FROM AUTHOR]

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Fresenius' Zeitschrift für Analytische Chemie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)