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K Danzer

Publications and source records attributed to K Danzer.

9 recordsLinked to original sources
PubMed2001

Selectivity and specificity in analytical chemistry. General considerations and attempt of a definition and quantification.

Selectivity and specificity are performance characteristics of analytical methods which are frequently used in analytical literature. In general, the terms are applied verbally and a quantification of selectivity and specificity is given rarely. Excepted are methods like chromatography and ISE sensoring which use individual quantities such as selectivity coefficients, indices and other parameters to characterize analytical procedures and systems. Here a proposal is given to characterize selectivity and specificity quantitatively by relative values in a range of 0 to 1 expressing so a certain degree of selectivity and specificity. By examples it will be shown that the derived quantities characterize analytical methods and problems in a plausible way.

Journal Article↗
PubMed2000

Method development for the determination of anthocyanins in red wines by high-performance liquid chromatography and classification of German red wines by means of multivariate statistical methods.

A simple and fast HPLC method without sample pretreatment is described for the separation of anthocyanins in red wines using a new pH-stable stationary phase. The linearity between peak area and concentration and ruggedness of the method were checked. Investigations were made about the safekeeping of red wine samples concerning anthocyanins. Classification of 52 different wine samples was performed by multivariate statistical methods.

Anthocyanins↗
PubMed2000

Non-invasive blood glucose monitoring by means of near infrared spectroscopy: investigation of long-term accuracy and stability.

Modern strategies in the treatment of Diabetes mellitus require frequent blood glucose tests. Near-infrared spectroscopy [NIR] is considered to be a method for non-invasive blood glucose testing. The present study evaluated the long-term accuracy and stability of the method. Spectra of 10 patients were recorded. An individual calibration models were calculated for each patient from spectra which were recorded at the beginning of the investigation. These models were then applied to calculate blood glucose values from spectra which were recorded 84 to 169 days later. The long-term accuracy and stability of the calibration models expressed as root mean squared error of prediction [RMSP] varied from 3.1 to 35.9 mmol/l and the error grid analysis [EGA] from 13 to 92% clinically acceptable values in zones A and B. The results of the investigation indicate that long-term monitoring of blood glocose by means of NIR-spectroscopy and individual calibration models over a period of 3 to 4 months is basically possible once long-term stability of the method will be improved. Further technological progress and a better understanding of the underlying physiological processes is necessary to achieve a level of accuracy, reliability and stability of the method as required for clinical application.

Adolescent↗
PubMed1997

Non-invasive blood glucose monitoring by means of near infrared spectroscopy: methods for improving the reliability of the calibration models.

The feasibility of using near infrared reflection spectroscopy for non-invasive blood glucose monitoring is discussed. Spectra were obtained using a diode-array spectrometer with a fiberoptic measuring head with a wavelength ranging from 800 nm to 1350 nm. Calibration was performed using partial least-squares regression and radial basis function networks. The results of different methods used to evaluate the quality of the recorded spectra in order to improve the reliability of the calibration models, are presented.

Adult↗
PubMed1996

Multisignal evaluation in ICP-MSDetermination of trace elements in Mo-Zr-alloy.

The existence of isobaric and polyatomic ion interferences has been considered to be a significant shortcoming of inductively coupled plasma - mass spectrometry (ICP-MS). In the special case of Mo-Zr-alloys problems caused by polyatomic ions are substantial. The determination of trace elements by using classical univariate linear regression of single signals or any correction equations presented by the instrumental software is impossible. There are various possibilities to overcome spectral interferences, in principle. The application of high-resolution ICP-MS, separation methods or alternative sample introduction systems is limited by the high cost and the apparative expenditure. In this report methods of multisignal calibration, like partial least squares (PLS) regression and canonical correlation analysis (CCA), are used to overcome isobaric or chemical interferences in ICP-MS. It is shown, that PLS and CCA are able to handle or tolerate, respectively, spectral interferences existing in a Mo-Zr-O-H-F system. The results of quantitative analysis provided by PLS and CCA were comparable.

Journal Article↗