scholarly journals Novel sample preparation technique for protein crystal X-ray crystallographic analysis combining microfluidics and acoustic manipulation

2009 ◽  
Vol 42 (4) ◽  
pp. 636-641 ◽  
Author(s):  
Stefano Oberti ◽  
Dirk Möller ◽  
Sascha Gutmann ◽  
Adrian Neild ◽  
Jürg Dual
Keyword(s):  
High Frequency ◽  
Pressure Field ◽  
Acoustic Radiation ◽  
Spatial Separation ◽  
Crystallographic Analysis ◽  
Protein Crystal ◽  
Preparation Technique ◽  
X Ray ◽  
Sample Preparation Technique ◽  
Fluidic Device

In order to perform X-ray crystallographic analysis, protein crystals are removed from their growing solution by means of a nylon loop, which is then mounted on a goniometer. As this process is repeated for a large number of crystals, there is a need for automation, especially with regard to the placement on the nylon loop. A novel technique involving the use of acoustic radiation forces and a micro-machined fluidic device is introduced here. After insertion into the micro-machined channel, the crystals are positioned in a row along its centre-line by excitation of a high-frequency standing pressure field, and then moved towards an orifice by applying a flow along the channel, which also ensures spatial separation. Once located in a defined orifice, the single crystals can be removed using a nylon loop. X-ray crystallographic analysis showed that application of ultrasound does not influence the diffraction properties of the crystals.

A Rapid, Low Cost, Manual Fusion Sample Preparation Technique for Quantitative X-Ray Fluorescence Analysis

1983 ◽  
Vol 27 ◽  
pp. 491-496
Author(s):  
Gerald D. Bowling ◽  
Iris B. Ailin-Pyzik ◽  
David R. Jones
Keyword(s):  
Raw Materials ◽  
Low Cost ◽  
Surface Preparation ◽  
Fluorescence Analysis ◽  
Preparation Technique ◽  
Muffle Furnace ◽  
X Ray ◽  
Fusion Device ◽  
Sample Preparation Technique

This study compares the quality of the fused samples obtained by three separate methods. The first set of samples was prepared by the method used at USGS in Denver and reported by Taggart and Whalberg (1). The second set was fused by our manual method and cast in graphite molds. The third set was fused in the Herzog HAG-12 automated fusion device.The manual fusion technique requires the use of a muffle furnace capable of 1100°C (2100°F) and graphite molds. No release agents such as KBr and LiBr are required since the disks release easily from the graphite. The 25mm diameter center of the “fire-polished” upper surface of the disk is used for analysis without further surface preparation. This method has been shown to be suitable for preparation of a wide variety of glasses and raw materials including burned dolomite, silicates* high zircon materials such as BCS-388, calcined alumina and alumina refractories.

The Dramatic Effect of Crystallite Size on X-Ray Intensities

1982 ◽  
Vol 26 ◽  
pp. 111-117 ◽  
Author(s):  
James P. Cline ◽  
Robert L. Snyder
Keyword(s):  
Spray Drying ◽  
Energy Minimization ◽  
Primary Source ◽  
Preferred Orientation ◽  
Preparation Technique ◽  
X Ray Diffraction ◽  
Spherical Form ◽  
X Ray ◽  
Sample Preparation Technique ◽  
Spherical Agglomerates

Preferred orientation has long been considered the primary source of systematic error involved in quantitative analysis by X-ray powder diffraction. Techniques of spherical agglomeration have been shown to eliminate preferred orientation provided that the agglomerate size is made sufficiently larger than the particle size. These techniques invariably employ the surface energy minimization of a liquid phase dispersed within a second fluid to create the spherical form desired. Spray drying has been the only method to date which has been successfully used to prepare spherical agglomerates suitable for X-ray diffraction. This study was undertaken to investigate possible deleterious effects of spray drying as a diffraction sample preparation technique.

Peritectic Melting Sequence of Bi-2212 and Bi-2212/Ag Measured Using Insitu XRD

1995 ◽  
Vol 39 ◽  
pp. 723-729
Author(s):  
S. T. Misture ◽  
D. P. Mathers ◽  
R. L. Snyder ◽  
T. N. Blanton ◽  
G. M. Zom ◽  
...  
Keyword(s):  
High Temperature ◽  
Thick Films ◽  
Tape Casting ◽  
Lattice Parameter ◽  
Residual Carbon ◽  
Preparation Technique ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sample Preparation Technique ◽  
Peritectic Melting

High temperature X-ray diffraction (HTXRD) was used to determine the peritectic melting sequence of BI2Sr2CaCu2O8 (Bi-2212) and Bi-2212+20 wt.% Ag thick films on MgO substrates. The optimized sample preparation technique includes tape casting the powders to form 10μm thick films, and reducing the residual carbon concentration to 1600 ppm by careful thermal treatment before the HTXRD measurements. Lattice parameter analyses were used to determine the compositions of solid solutions present in the partially-melted state. Pour phases form during melting Bi-2212 or Bi-2212 + Ag, including an unidentified phase, (C0,4Sr0,6CuO2, (Ca1,4Sr0,6)CuO3, and (Sr,Ca)0.

Determination of the Relative Amounts of α-carbamazepine and β-carbamazepine in a Mixture by Powder X-Ray Diffractometry

1990 ◽  
Vol 5 (3) ◽  
pp. 155-159 ◽  
Author(s):  
Raj Suryanarayanan
Keyword(s):  
Weight Fraction ◽  
Preparation Technique ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Sample Preparation Technique ◽  
Integrated Intensity ◽  
Diffraction Patterns ◽  
Good Agreement

AbstractA powder X-ray diffraction technique has been developed to quantify the relative amounts of α-carbamazepine (A) and β-carbamazepine (B) when they occur as a mixture. The theoretical basis of this technique was developed in 1948 by Alexander and Klug (Anal. Chem., 20:886-889). The powder X-ray diffraction patterns of A and B revealed that the line with d-spacing of 10.1 Å was unique to A. The ratio of the integrated intensity of the 10.1 Å line in a mixture of A and B, to the intensity of the 10.1 Å line in a sample consisting of only A, was calculated as a function of weight fraction of A in the mixture. These ratios were also experimentally determined, and there was a good agreement between the theoretical and experimental intensity ratios. The particle size of the samples, the sample preparation technique and the experimental conditions were controlled so as to eliminate the major sources of error in powder X-ray diffractometry. In order to minimize preferred orientation of the particles, a sample holder was specially fabricated.

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