Atomic absorption spectrometry.
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Animals↗
Biomedical subjects
W Slavin
Publications and source records attributed to W Slavin.
Direct-calibration method for determination of aluminum in serum is comparable with the protein-precipitation technique.
We compared results by two methods for serum Al determination: matrix modification with direct calibration in a stabilized-temperature platform furnace (Clin Chem 28, 2139, 1982) and a technique involving extraction with nitric acid before atomic absorption spectrometry (Clin Chem 30, 1216, 1984). The two methods gave similar results with use of either a deuterium or a Zeeman system of background correction, but gave different slopes for standard additions (mA X s per microgram/L), depending on the Al content of the serum, an effect not seen with aqueous solutions. These differences do not affect the accuracy of the Al determination up to 150 micrograms/L.
Aluminum↗
Determination of phenylalanine in serum using reversed-phase liquid chromatography and fluorescence detection.
A liquid chromatography procedure is reported for determining phenylalanine in small volumes of serum. A 10-microliter volume of serum was deproteinized with ethanol and an aliquot was derivatized with dansyl chloride reagent. The dansylated phenylalanine and the norleucine internal standard were separated using reversed-phase chromatography and measured with a fluorescence detector. Linearity was excellent over the range 50-800 mg/l. Within-run precision was better than 4%. Total analysis time including chromatography was approximately 40 min. As little as 300 pg of dansylated phenylalanine was detected.
Chromatography, Liquid↗
Determination of polyamines by liquid chromatography and precolumn labelling for fluorescence detection.
Procedures are described for the separation and detection of picomole quantities of putrescine, spermidine, and spermine by liquid chromatography. The polyamines are labelled by precolumn derivatization with dansyl chloride followed by reversed-phase chromatography with a methanol and water mobile phase. The derivatized polyamines are measured with a fluorescence detector using an excitation wavelength of 340 nm and emission wavelength of 515 nm. The polyamines are eluted within 12 min and 0.5 ng of each could be detected. Some preliminary data on urine samples is presented.
Chromatography, Liquid↗
A fluorescence detector for high-pressure liquid chromatography.
We describe a fluorescence spectrophotometer adapted with a micro quartz flow cell to record the output of modern liquid chromatographs. The optical system is double beam in that the light source variations are cancelled out by a second photomultiplier, thus enhancing the sensitivity of the technique. The emission spectra may be scanned by stopping the flow in the chromatographic column and scanning the fluorescence detector. Many specific applications have been studied: polycyclic aromatic hydrocarbons, several vitamins, porphyrins, methyl anthranilate, etc. These are studied in natural samples and it is shown that the specificity of the fluorescence detector frequently obviates the need for sample preparation. The sensivitity available with the fluorescence detector for fluorescing compounds is often much greater than is available with variable-wavelength ultraviolet spectrophotometers. We report picogram-level detectability in real samples for many of the compounds that we have studied.
Animals↗