SPEX SamplePrep X-CELLS® are used throughout the world for fast, dependable, reproducible running of liquid samples in XRF spectrometers. They are designed to fit into the major suppliers of XRF spectrometers such as PANalytical, Rigaku, Bruker and Thermo Instruments. The requirements of the application will dictate the type of X-CELL® and which window material to use. Made of contaminant-free polyethylene, closed X-CELLS® are available in both 31 mm and 40 mm sizes to fit most spectrometers. For special applications there are 31 mm Double Open End and Micro X-CELLS® and a 43 mm Closed Cell for Horiba Sulfur Analyzers. The patented closed X-CELL®design features a snap-open seal for venting volatile samples and a reservoir cup for catching any liquids that expand through the vent. This assures the analyst of a smooth, flat window for improved precision, yet guards against spillage in inverted-optic spectrometers. A roughened surface within the reservoir cup facilitates labeling. Each closed X-CELL®consists of a cup and snap-on ring. For routine liquid samples, the cup is filled with liquid, a piece of film is spread over the top then the snap-ring is pushed down over the cup to form a flat drum-like window. The cell is turned over and the snap-post on the rear can be pushed to break the seal and to permit venting of trapped bubbles or expanded liquid while the sample is run.
The filled X-CELL® is then positioned in the spectrometer mask. They can also be used to run solution residues and small quantities of pastes or powders. For solution residues, the film window is prepared as for solutions then dished slightly with the rounded end of a glass rod. A drop of solution placed there and warmed under an IR lamp dries to a smudge for analysis. If powder or paste is spread on the surface and another piece of film overlaid before snapping on the ring, the sandwiched sample is ready for X-ray analysis. The 3527 40 mm X-CELL®can also be used to hold crumbling 31 mm sample disks.
SPEX SamplePrep also supplies versatile Double Open End X-CELLS® which are ideal for many unusual or hard-to-handle samples: slurries, sludges, pastes, viscous materials such as glue, tar, or RTV sealant, metal films and machine parts, etc. The 3571 X-CELL®has a body open at both ends, two snap-on rings, and a collar to hold film in place while the ring is being applied. After window film has been attached to one end of the cell, it can be inverted, and the sample placed, poured, dabbed, or otherwise located in the cell, directly against the window. The top of the 3571 X-CELL®can then be left open or sealed with film.
The 3577 Micro X-CELL®is ideal for small air-sensitive or hazardous samples. While it fits in the standard 31 mm sample holder, the window is 6.3 mm in diameter, and only 0.5 mL fills it up. Collimate your beam down to reduce scatter and you’re ready to go. The Micro X-CELL®can be run with an open or window back, but it will also accept a 7 mm x 13 mm serum bottle closure for injection, purging, or the isolation of special samples.
BUBBLE-FREE CELL INSERT
The Bubble-Free Cell Insert is a simple, patented insert for the 40mm XRF liquid cell (3527) which prevents trapped air from forming a bubble under the window film when the cell is used in the upright position. The 3527I Bubble-Free Cell Insert is pushed into a cell before the sample is added and forms an inverted-cone shelf under which air bubbles can be trapped once the cell is filled and sealed. In many XRF systems, liquid cells are run in an inverted position, so any bubbles rise to the back of the cell and do not interfere with the analysis. The drawback of this “inverted optics” configuration is that if the window film ruptures, the sample can spill and potentially contaminate or damage the spectrometer. However, an increasing number of samples are being run in so-called “normal optics” XRF spectrometers, where the X-ray source is above the cell instead of underneath. Bubbles trapped during assembly of the cell can collect against the window, displacing the sample and attenuating the X-rays reaching the sample and emitted by it. To use an X-CELL®fitted with a SPEX SamplePrep Bubble-Free Cell Insert, assemble the cell, invert it, and tap it. Bubbles should rise through the hole in the insert and when the cell is turned right-side-up the bubbles will be trapped below the insert’s shelf, away from the window film. Most but not all bubbles get into an X-CELL®during assembly and some samples outgas when heated by the X-ray beam. Tests have shown that a pinhole near the edge of the window film will allow such gases to escape without bulging or rupturing the film.The 3527I Bubble-Free Cell Insert coupled with the 3527 X-CELL®will fit normal optics XRF spectrometers made by Diano, Rigaku and Shimadzu Scientific Instruments, Inc.