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PubMed1977

[Extraction method for the simultaneous determination of sodium, potassium, calcium, magnesium, iron, copper, zinc and manganese in organic material using atomic absorption spectrophotometry (author's transl)].

Determination of sodium, potassium, calcium, magnesium, iron, copper, zinc, and manganese in organic material is possible with one digestion using the described extraction method. Data for sodium, potassium, calcium, magnesium, iron, and manganese agree well with those obtained by conventional methods [1, 2, 4]. For quantitative determination of copper and zink the extraction method is superior to dry ashing at 450 degrees C [1, 4]. In general the extraction method ist preferable to dry assing, because the amount of sample, time and costs can be reduced essentially using the described method.

Calcium↗
PubMed1978

Interaction of chlorpromazine with organic solvents and fatty acids as studied by UV-spectrophotometry.

The magnitude of the UV-spectral change of chlorpromazine increases in the presence of increasing concentrations of alcohols or fatty acids and with increasing chain length. A maximum is reached with 14.0- or 16.0-fatty acids. The differential spectrum is still larger with unsaturated fatty acids, a maximum effect being obtained with one cis-double bond. The spectral change is abolished by chaotropic and enhanced by antichaotropic agents.

Alcohols↗
PubMed1981

Determination of calcium intake of help of atomic absorption spectrophotometry.

In a dietary survey, large numbers of a wide variety of food samples have to be analyzed. The atomic absorption spectroscopy (AAS), with its simplicity, accuracy and rapidity, suggests itself for determination of many elements in such a case. In this investigation, calcium determination by AAS is reviewed. Analytical parameters, interferences and their control are studied. Food samples are dry ashed and treated so as to eliminate silicates. Most serious interference comes from phosphates and is successfully controlled by addition of lanthanum. Calcium is determined in the range 2-10 ppm with a sensitivity of 0.1 ppm. Single food samples and samples representing food mixtures are analyzed, and calcium intake of different population groups is computed. In most cases, results compare favourably well with those obtained from food composition tables. Calcium intake in the Netherlands both of the average per caput and of chosen population groups is found to cover the recommendations except for infants. Differences do exist between intakes of different groups and in different seasons.

Age Factors↗
PubMed1985

Determination of ethinyloestradiol in the presence of norethisterone by derivative-difference spectrophotometry.

A simple and direct method for the determination of ethinyloestradiol as a minor component in the presence of norethisterone and in oral contraceptive tablets is presented. The method is based on measuring the signal intensity, d delta A/d lambda and d2 delta A/d lambda 2, of the generated first and second derivative spectra of the delta-absorbance curves obtained by measuring solutions in methanol and methanol-sodium hydroxide at certain wavelengths. The method has been applied to the determination of ethinyloestradiol in oral contraceptive tablets, with a coefficient of variation of less than 2%.

Ethinyl Estradiol↗
PubMed1985

Reflectance spectrophotometry in the human ocular fundus.

Spectrometric investigations were carried out in normal human maculae and optic discs and in those with pathological findings (50 eyes in total). Reflection spectra were measured by illumination of various points of the fundus, using a highly sensitive photon-counting technique. It is necessary to distinguish diffusely reflected light from regularly reflected light, as we found marked differences in the spectra of diffusely reflected light between normal eyes and those with pathological findings. In optic atrophy cases, the intensity of light reflected from the optic disc (510-600 nm) was remarkably higher than normal. In findings of proliferative diabetic retinopathy, the reflected light intensity showed a steeper slope, beginning at 580 nm, in comparison with normal findings.

Diabetic Retinopathy↗