Solid Sample Preparation Research Articles

High-performance liquid chromatographic determination of oxmetidine in human plasma: comparison of liquid—liquid and liquid-solid extraction techniques

A preliminary liquid—solid sample preparation scheme (LSE) for the HPLC determination of oxmetidine in human plasma is compared with the existing liquid—liquid extraction. The LSE method shows great practical advantages, such as ease of preparation, saving of time, and smaller sample volumes, but needs to be investigated further with respect to robustness and the removal of an endogenous compound that interfered with the quantitation of oxmetidine at low concentrations.

Slurry Atomization Direct Flame Emission Determination of Na and K in Hot Dogs

This report describes initial development of a slurry atomization method for rapid, cost-effective, near-direct determinations of sodium and potassium in hot dogs by flame emission. Samples were briefly homogenized in water. Na and K were thereby solubilized. Hot dog slurries were directly introduced with a Babington nebulizer into a clog-free air-natural-gas burner. This cool flame eliminated ionization. Instrumental calibration was performed merely with separate aqueous standard solutions of NaCl and KCl. Ionization suppressants, internal standards, standard additions, matrix correction factors, matrix modifiers and matrix matching schemes were all found to be unnecessary for hot dog slurries directly analyzed with this system. The overall slurry atomization method eliminated the need for acids, fume hoods and lengthy sample preparation such as wet or dry ashing. Quantitative accuracy was achieved for near-direct determinations of weight percent Na and K in hot dogs. Total solid sample preparation plus analysis times were ≤ 5 min.

Rapid high-performance liquid chromatographic method for the measurement of atenolol in plasma using UV detection

A rapid, selective and reproducible high-performance liquid chromatographic method has been developed for the measurement of the β-adrenoceptor blocking drug atenolol in small (400 μl) volumes of plasma. Following solid phase sample preparation using Bond-Elut TM mini-columns the compound is separated by high-performance column liquid chroamtography on a microparticulate (6 μm) cyano column using acetonitrile—ammonium dihydrogen phosphate (4:96) containing triethylamine (0.25%, v/v) as the mobile phase, and the absorption of the column effluent is monitored at 224 nm. The practical limit of quantitation, based upon an assay volume of 400 μl, is 25 ng/ml for atenolol. The average coefficient of variation is 3.1%.

Preparation of InAs ‐ InSb Alloys

The preparation of solid samples of alloys suitable for optical transmission and electrical measurements is considered. Cross sectional slices of ingots produced by slow directional freezing and slow zone recrystallization have been investigated by x‐ray powder photograph techniques, and results are given for the variation of composition with position along ingot and for homogeneity of the slice. Annealed powder samples have been used to check the previous data for the variation of lattice parameter with composition. Specimens have also been observed by photomicrograph methods and by use of an electron probe microanalyzer. The x‐ray, photomicrograph, and microanalyzer data are compared for various samples with different degrees of homogeneity.

Preparation of Uniform Solid Samples for Radioactive Assay

THE preparation of uniform solid samples of radionuclides is of paramount importance in radio-chemical assay, using end-window Geiger-Muller counters, especially for radionuclides emitting low-energy beta-radiation. For comparative measurements (using identically mounted samples), it is essential that all the deposits should be uniform and of the same dimensions, so that the factors due to absorption and scattering in the sample are constant.

Appendix 2. Preparation of solid samples for assay of 14C

<i>Appendix</i> 2. Preparation of solid samples for assay of 14C

A Technique for the Preparation of Grease or Solid Samples Dispersed in Grease-Like Media for Examination with the Electron Microscope

The nature of grease as a dispersion of solid particles in oil is briefly discussed, and the value of the electron microscope in studying this solid phase is pointed out. The requirements of a satisfactory grease specimen mounting technique are outlined and a new technique fulfilling these requirements is described. Electron micrographs are presented which demonstrate the usefulness of the technique in disclosing pertinent information on grease structure. The factors involved in the preparation of powder specimens for electron micrography are discussed in relation to the adoption of a modification of the grease mounting technique for this purpose. The modified technique for powders is outlined and illustrated with micrographs.