Acetone as solvent in flame-photometric determination of lithium in serum.
Abstract The effect of some water miscible organic solvents on the flame photometric emission of Li is discussed. A simple procedure is described with acetone as diluting solution giving a ten to twenty fold increase in sensitivity.
Micro flame photometric determination of sodium, potassium, and calcium in serum with organic solvents.
The effect of organic solvents on the flame photometric emission of certain elements in petroleum products has been reported (1). Propanol, hutanol, and acetone have been used in the flame photometric determination of sodium and potassium in serum, but these organic solvents were not used routinely, “as it was feared that complications might arise in practice owing to their volatility and to the restricted solubility of NaCl and KC1 in some solvents” (2). Apparently no extensive investigation has been made of the effect of organic solvents on the emission spectra of the cations of blood serum. We have investigated the use of organic solvents to extend the sensitivity of the flame photometer in the direct determination of sodium, potassium, and calcium, and to make practical the analyses of extremely small biological specimens. Our investigation of the effect of organic solvents on the emission spectra of sodium and potassium (3) indicated that, of the solvents studied, acetone produced the greatest enhancement of emission spectra. Less enhancement was produced by methanol, ethanol, propanol, and isopropanol in the order named. Acetone increased the spectral emission of sodium 17-fold in relative per cent transmittance and potassium 13-fold as compared with the aqueous solvent. This investigation also indicated that bovine albumin* had no effect on sodium and potassium spectra. Further study of organic solvents has been made to test their enhancement effect on the emission spectra of sodium, potassium, and especially of calcium. The use of an aqueous solvent for the direct microphotometric determination of sodium, potassium, and calcium in a single biological specimen has been reported (4).
Photoreflectance characterization of vanadium-doped GaAs layers grown by metalorganic vapor phase epitaxy
Abstract We characterized the vanadium-doped (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy. The conductivity of the samples is checked by the Hall effect measurements, and it is n type with electrons concentration ranging from 2×10 13 to 2×10 17  cm −3 . We used the photoreflectance technique (PR) to study the effect of vanadium doping on the optical properties of GaAs. Our experimental results show that the built-in electric field F and the broadening parameter Γ 0 increase with V-doping concentration. Furthermore, the temperature dependence of the built-in electric field and the broadening parameter of GaAs:V samples have been investigated by PR. It has been observed that these parameters increase with increasing temperature. The decrease of the built-in electric field with decreasing temperature is due to the photovoltage effect.We characterized the vanadium-doped GaAs (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy.