Micro manufacturing equipment

Workers at TA Instruments UK, manufacturer of thermal micro-analysis equipment, have given details of the model TA 2990 system. They give examples of its application to thermal and morphological problems [339]. 

CFR211.46 states that a) Adequate ventilation shall be provided, b) Equipment for adequate control over air pressure, micro-organisms, dust, humidity, and temperature shall be provided when appropriate for the manufacture, processing, packaging, or holding of a drug product, c) Air filtration system, including prefilters and particulate matter air filters, shall be used when appropriate on air suppliers to production areas. ... 

An upgraded version of the micro reaction system, the mikroSyn II, is equipped with a third rotary pump. Additional, different micro fluidic components provided by the manufacturer can be incorporated in the system. 

R 18] [A 1] Each module is equipped with a heater (H3-H8) and a fluidic cooling (C03-C06). Temperature sensors integrated in the modules deliver the sensor signals for the heater control. Fluidic data such as flow and pressure are measured integrally outside the micro structured devices by laboratory-made flow sensors manufactured by silicon machining. The micro structured pressure sensor can tolerate up to 10 bar at 200 °C with a small dead volume of only 0.5 pi. The micro structured mass flow sensor relies on the Coriolis principle and is positioned behind the pumps in Figure 4.59 (FIC). For more detailed information about the product quality it was recommended to use optical flow cells inline with the chemical process combined with an NIR analytic or a Raman spectrometer. 

X-ray spectrometry has benefited, as have other physico-chemical analysis methods, from the many recent advances in electronics and micro-computing. We have seen that, for qualitative analysis, software is used for the automatic identification of peaks. For quantitative analysis, the majority of equipment manufacturers provide highly extensive correction software packages. Finally, the automatic handling of samples in the spectrometer is well established (sample handlers with a capacity of 72 to 100 samples). 

Rates of hydrolysis were measured on a Varian Cary 219 UV spectrophotometer equipped with a Haake constant temperature bath. A stirred batch tank reactor was placed in a water bath maintained at 26.0 0.1 C and the solution was transported to a micro flow UV cell located in the spectrophotometer via silicone rubber tubing using a precision flow peristaltic pump (MHRE 22) manufactured by the New Brunswick Scientific Company. 

Many systems that have been used consist of a commercial fluorimeter fitted with a micro flow-through cell. Descriptions of such systems can be found in the papers by Katz and Pitt , Cassidy and Frei and Roth and Hampai , while the manufacturers of the fluorimeters used also market flow cells (Aminco and Turner Assoc.). Conmercial equipment especially designed for use in HPLC has also been available for several years, with emission lines and filters (Siemens, Dr. Ing. Herbert Knauer, Laboratory Data Control, DuPont, Varian), as well as with monochromators (Winopal Forschung, Perkin-Elmer, Schoeffel, Aminco, Turner Assoc., Jasco). Cells of these designs are small enough (ca. 20 gl) to be able to give a small contribution to the peak width with suitable connection lines and electronics. However, adequate information on this point is not generally available, in some instances perhaps because the reaction systems frequently used with these instruments contribute much more to the peak width. 

The aim here is simply to present an overview of the various features on offer. The range of instruments extends from differential scanning calorimeters in a suitcase for on-site use to spatially resolved micro-thermal analysis equipment for samples as minute as 2 x 2 fim. Between these rather extreme examples there is a wide choice of commercial DTA and DSC equipment which allows samples to be studied at temperatures ranging from — 150°C to about 1600°C. For higher temperature measurements (above 1600°C) the equipment becomes increasingly more specialised. The detailed specification of equipment is often difficult (sometimes impossible ) to decipher - there appears to be no common practice between manufacturers. Information can best be obtained by raising questions directly with the manufacturers. Even so, hands-on experience is to be recommended when choosing equipment. 

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