Modification of a Perkin-Elmer 603 atomic absorption spectrophotometer by adding a high-intensity tungsten-halogen lamp for background correction significantly improved the detection limit for elements that have analytical wavelengths in the near-ultraviolet and visible regions. Chromium in human serum and urine can be measured, with a simplified sample-handling technique, in concentrations of ...

H/D isotope effect on the circular dichroism spectrum of methyl α-D-glucopyranoside in aqueous solution has been analyzed by multicomponent density functional theory calculations using the polarizable continuum model. By comparing the computational spectra with the corresponding experimental spectrum obtained with a vacuum-ultraviolet circular dichroism spectrophotometer, it was demonstrated th...

Instruments. NMR spectra were obtained with Bruker AC-300 and Varian UNITY-500 spectrometers. Mass spectra were obtained with Perkin Elmer Sciex API 365 electrospray ionization (ESI) and Bruker Biflex III matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) instruments at the University of Wisconsin Biotechnology Center. Ultraviolet and visible absorbance was recorded with a C...

We examined the feasibility of measuring absorbance in the far ultraviolet for serum protein determination with a medium-priced, double-beam spectrophotometer. The method has been simplified by using an automatic dilutor to dilute the serum, and a flow-through cell and recorder in conjunction with the spectrophotometer. Because it is only necessary to dilute the serum and determine its absorban...

ETHODS FOR DETERMINATION of deuterium oxide (D00) using infrared spectrophotometry have been reported by a number of workers (1-3). These methods permit determination of D00 in biologic fluids with an accuracy and precision satisfactory for determination of total body water and similar problems. The use of an infrared spectrophotometer for measurement of 1)20 in water and biologic fluids offers...

Quantification of RNA is essential for various molecular biology studies. In this work, three quantification methods were evaluated: ultraviolet (UV) absorbance, microcapillary electrophoresis (MCE), and fluorescence-based quantification. Viral, bacterial, and eukaryotic RNA were measured in the 500 to 0.05-ng microl(-1) range via an ND-1000 spectrophotometer (UV), Agilent RNA 6000 kits (MCE), ...

Ultraviolet UV absorbance measurements are subject to significant error using a standard spectrophotometer when particles or aggregates that scatter light are present. True UV absorbance for highly turbid waters should be measured using integrating sphere IS spectrophotometry that allows the collection of reflected and transmitted radiation simultaneously. This is especially important when the ...

The current study was intended for isolation of bioactive polyphenolic compounds from methanol extract of Justicia Gendarussa and their subsequent characterization. The flavonoid compounds were isolated and identified by using thin layer chromatography (TLC), were qualified by using reverse phase high performance chromatography (RP-HPLC). Their structures and chemical bonds were analyzed using ...

High-intensity laser pulses covering the ultraviolet to terahertz spectral regions are nowadays routinely generated in a large number of laboratories. In contrast, intense extreme-ultraviolet (XUV) have only been demonstrated using small sources including free-electron facilities [1-3] and long high-harmonic generation (HHG) beamlines [4-9]. Here we demonstrate concept for compact XUV source ba...