Aluminium heating block

A TurboVap Workstation is used to dry beakers in an anodized aluminium heated block with a nitrogen purge at 104°C or 108°C. 

A heater/evaporator with separate aluminium heating blocks (three sizes compatible with the vials glassware) and 6-position nitrogen purge concentrator with tubing for connection to nitrogen generator... 

Aluminium heating block designed for use with the reaction cell... 

Because of the resistance of e.g. arsenobetaine to wet and pressurized decomposition with nitric acid, higher temperatures and more effective acids are required for complete decomposition of materials that contain resistant arsenic compounds. For years this was accomplished with mixtures of nitric and perchloric acids or mixtures of nitric, perchloric and sulphuric acids (Pershagen et al., 1982). For example, urine was decomposed by pipetting 2 mL of the sample into test tubes (18x150mm) held in an aluminium heating block (Peter et al., 1979). The digesting acid (1 1 mixture of concentrated nitric and perchloric acid) was added and the heating block was kept on a hot plate at approx. 200 °C for 4-6 h until approx. 0.5 mL liquid remained. This liquid was then used after appropriate dilution for arsenic determination by hydride AAS. 

A similar procedure, evaluated for the determination of selenium in body fluids by hydride / S, has been successfully used for arsenic as well. The flasks are the same as already described above with a long neck and 40 mL volume. However, flasks of similar design (e.g. Kjeldahl flasks) may be used as well. The procedure is as follows. 0.5 mL serum, whole blood or urine is placed into the digestion flasks. If necessary a sample volume of 1.0 ml may be also used. After this 1 mL of nitric acid (65% w/v) is added, the digestion flask placed into the aluminium heating block, and the block slowly heated to 140 °C. This temperature is maintained for 25 min and then cooled to room temperature. 0.5 mL (96% w/v) sulphuric and 0.2 mL (70% w/v) perchloric acid is added to the cool solution. The subsequent programme consists of slowly heating (approx. 15 min) to... 

Aluminium heating block with holes for digestion tubes. 

Aluminium heating block, 50 mm thick, with cylindrical holes in which the digestion vessels fit. 

Sample vessel 3. Receiver and vessel for determination 4. Aluminium heating block 5. Lower connecting tube 6. Steam inlet tube 7. Aluminium heating block ... 

Humidified denaturation chamber. A simple homemade version may be constructed by setting an aluminium heat block to 94"C and covering the block with a plastic lid containing a layer of Kimwipes moistened with H O around the inner rim (Figure 2.5). 

Experimental Procedure. The resin is washed with methanol and a small portion (1-3 mg) is transferred to an Eppendorf tube. To this tube is added NF-31 solution (0.002 M in acetonitrile, 200 pi). The tube is heated in an aluminium dry heating block at 70° for 8 min. The resin is washed extensively with MeOH (3x), DMF (3x), and DCM (3x). The presence of free... 

Kg. 36. Sample holder for polymer foils made of brass (left picture) The sample is covered by Aluminium foil to ensure thermal contact. A 0.25 mm thick thermocouple is embedded into the sample. For rapid heating the sample holder is driven by a piston into the preheated heating block (right picture). The separation of the heating block into two parts allows the block to clamp the sample holder thus ensuring thermal contact. Cooling is possible by pressurized air. The beam passes through the 8 mm bore. 

A block diagram of a TL instrument, which is composed of a light-proof box with a heating block to which the sample and a thermocouple are attached, is presented in Figure 6.20. An aluminium window allows the sample to be irradiated before heating. The chamber can be evacuated or purged with an inert gas. The TL sensor is a high-sensitivity photomultiplier with a dark... 

One such monolithic carbon has been produced by Sutcliffe Speakman Carbons and is described by Tamainot-Telto and Critoph [17]. Powdered activated carbon is mixed with a polymeric binder, compressed in a die and fired to produce a monolith of the desired shape, with a density of 713 kg/m and conductivity of 0.33 W/mK. A heat transfer coefficient of 200 W/m K has been measured between the blocks and aluminium fins. 

In heat-flow calorimeters, it is particularly important, as already indicated in Section II, that the heat sink remain, throughout the experiment, at a constant temperature. The construction of the heat sink and thermostat in the Calvet apparatus is shown in Fig. 3. The calorimetric element fits into a conical socket (A), cut in a cylindrical block of aluminium (B). The block is positioned between the bases of two truncated cones (C and C ), placed within a thick metal cylinder (D). The metal cylinder is, in... 

The hquid is constantly mixed by the shearing action of the gas stream which reduces the hkehhood of sample boil-over in the heated aluminium block. 

Urine (5 ml) urine spiked with 0.2% (v/v) isopropylamine is placed in a screw-capped 15-ml vial [28]. Pelleted potassium hydroxide (3 g) is added before sealing the vial with an airtight polytetrafluoroethylene-lined septum cap. Potassium hydroxide raises the pH of the sample to ensure that the amines are present as volatile bases. The vial is heated in an aluminium block at 90 C for 20 min. While still in this block, 2 ml head-space gas is withdrawn through the septum with a disposable syringe and injected immediately on the gas chromatography column. The operating temperatures of the column, injector port and detector unit are 70 C isothermal, 150 C and 200 C, respectively, with nitrogen carrier gas at 60 ml/min. This allows quantification of TMA and other amines. TMA N-oxide is measured after quantitative reduction into TMA. For this, titanous chloride (30%, w/v 0.2 ml) is added to 2 ml urine in a screw-capped vial and incubated for 30 min at room temperature. The sample is then diluted ten-fold with distilled water and analysed as described above. The result represents the sum of TMA and TMA N-oxide present in the sample. 

Fig. 1. Shallow aluminium block-bath for heating many test-tubes.

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