Powder sampling syringe

The use of NIRA for monitoring constituent levels in infant formula products began in the late 1970s. Protein, fat, content, and total solids monitoring were the targets of initial efforts in this area [11]. The early work paralleled the development of NIRA for dairy applications. Instrumentation was relatively simple at this point, utilizing a flow cell in the place of the powder sample holder. Samples were prewarmed and injected into the flow cell manually via syringe. 

Fig. 9.4.10 Apparatus for the gas flow-arc plasma method. The apparatus is composed of two components. The upper part is a glass Dewar, which accumulates small particles in a cryogenic matrix on the trim cooled with liquid nitrogen (LN). Sorv, inlet of organic vapor Syr, syringe for transferring produced colloids under anaerobic conditions RP, rotary pump S, target sample. Lower part is for plasma discharge. A BN furnace has gas inlets (G) and is specially designed for Ar gas to flow in screwed stream hence the plasma is emitted in a jet flame due to a plasma pinch effect. The black parts are copper electrodes cooled by water. In order to maintain a constant spacing between the surface of sample and tbe upper electrode, the sample position can move vertically so that the current through the sample to the upper electrode is precisely controlled and constant. This is very important to produce powders with a narrow size distribution.

Solid-phase extraction, or liquid-solid extraction, can overcome several of these problems. Solid-phase extraction techniques use membranes or small disposable syringe-bairel columns or cartridges. A hydrophobic organic compound is coated or chemically bonded to powdered silica to form the solid extracting phase. The compounds can be nonpolar, moderately polar, or polar. For example, an octadecyl (C jj) bonded silica (ODS) is a common packing. The functional groups bonded to the packing attract hydrophobic compounds in the sample by van der Waals interactions and extract them from the aqueous solution. 

For the experimental standard procedure 15.0 g a-pinene oxide was stirred in 30.0 g of toluene, brought to reaction temperature in a flask equipped with a double wall cooling system and mixed with 2.0 g of powdered catalyst under careful temperature control Product samples were taken from reaction mixture by means of a syringe filter and analyzed by gas chromatography. The analysis was performed on a Siemens RGC 202 using a 60 m capillary column SE 54. The injection temperature was 200°C Products were identified by GC-MS or by comparing them with authentic samples. 

High-risk samples All biological samples have the potential to contain infective viruses such as hepatitis or human immunodeficiency virus. Dust and powders can cause serious problems if inhaled. Automation has the advantage that human contact with these types of samples is reduced. However, some automated techniques, e.g., the use of syringes, can generate aerosols containing infectious droplets. Thus, it is important to evaluate the operation of automated systems and house them in appropriate environments. 

Cumene (0.25 kPa) diluted in Argon was fed with a constant flow of 20 ml/min (STP) into the reactor, while the flow rate of the jet stream was varied. Samples were taken with a syringe and analysed in a GC. Carbon mass balances were better than 95%. The extrudates were crushed to three different sizes (diameter = 0.15, 0.085, 0.065 cm). The reactions were carried out for 3 hrs. The extrudates were calcined at 480°C in air for 12h between experiments. Kinetic studies with the powder form (0.5 pm) were measured in a plug flow reactor at a constant contact time (WHSV=0.7 g cat/(g hr))... 

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