Standardized apparatus

The difficulties of working with small quantities of liquids are much greater than with small quantities of solids. For example a competent worker can, and does in fact, often work with 100 mg, of solid without any special apparatus. With liquids this is often not practicable because of the much greater losses entailed, particularly when it is realised that one ordinary-sized drop weighs about 50-100 mg. The account which follows gives details of modifications of standard apparatus suitable for the semi-micro scale defined above. 

Much can be done with such standard apparatus in borosilicate glass as — Round-bottomed flasks 5 ml., 10 ml. and 25 ml. 

The flash-point is a measure of the ease of ignition of the liquid. It is the lowest temperature at which the material will ignite from an open flame. The flash-point is a function of the vapour pressure and the flammability limits of the material. It is measured in standard apparatus, following standard procedures (BS 2000). Both open- and closed-cup apparatus is used. Closed-cup flash-points are lower than open cup, and the type of apparatus used should be stated clearly when reporting measurements. Flash-points are given in Sax s handbook, Lewis (2004). The flash-points of many volatile materials are below normal ambient temperature for example, ether —45°C, petrol (gasoline) —43°C (open cup). 

When testing the effect of low temperatures on elastomers it is rarely sufficient merely to enclose the standard apparatus in a refrigerated chamber special procedures are necessary. The relevant standard is BS 903 Part A13. Method for determination of stiffness at low temperatures (Gehman test). 

Labelling is a very important feature of laboratory management. Properly designed and used labels ensure that the identity and status of reagents, chemical standards, apparatus and equipment are always clear to users. There are various requirements that the label on a container should satisfy ... 

High-quality data from a standardized apparatus that produces consistent results are lacking. 

Reid Vapor Pressure (RVP) - The pressure caused by vaporized part if a liquid and the enclosed air and water vapor as measured under standardized conditions in standardized apparatus, the result given in psi at 100 °F, although normally reported as RVP in lbs. RVP is not the same as the true "vapor pressure" of the liquid, but provides a relative index of the volatility of a liquid. 

USP Guidelines for setting Dissolution standards Apparatus 2—Paddle adopted two Calibrator Tablets adopted... 

Of all these types, Apparatus 1 and 2 are the most widely used around the world, mostly because they are simple, robust, and adequately standardized apparatus designs, and... 

QA requires the efficient analysis of many samples to support routine production release and stability programs. Methods are typically established in the analytical development group. Efficiency and convenience issues, including the speed of media preparation and the relative convenience of data handling and documentation, are important here. While compliance is important in all aspects of the pharmaceutical industry, QA functions must approach compliance perfection. Depending upon the facility, the automated apparatus may be tailored to specific methods with fixed configurations. Dissolution methods may be routine enough that a custom system, optimized for productivity, may be justified. Compliance of USP and use of industry standard apparatus is important to maintain compatibility with other company laboratories or in the case contract laboratory services are required. 

Fire point the lowest temperature at which, under specified conditions in standardized apparatus, a... 

A 500-ml standard apparatus (round bottom flask, several inlets for stirrer, reflux condenser, nitrogen flux or vaccum, thermometer, heating bath) is evacuated and Ailed with nitrogen. 5 g of poly(vinyl alcohol) are then placed in the flask (see Example 5-1) and dissolved in 100 ml of distilled water by stirring at 60 °C next are added 2.2 g of ox-ethylated nonylphenol and 0.4 g (1.8 mmol) of ammonium peroxodisuifate buffered... 

Four 250 ml standard apparatus (round bottom flask, several inlets for stirrer, reflux condenser, nitrogen flux or vaccum, thermometer, heating bath) are filled each with 38 ml of distilled water and 405 mg (1.8 mmol) ammonium peroxodisuifate.To the fourth flask, additionally 90 mg of an alkylbenzene sulfonic acid sodium salt emulsifier (linear Cl 0-C13 aikyl chains, 70% in water) are added. After reaching an internai temperature of 80 °C,3 g of a monomer emulsion (prepared according toTabie 3.13) are added to each of the four batches. Within an induction phase of 15 min the reactions start. This is visuaiized by the pale blue coloration of the content of the flasks.Then the remaining monomer emulsion is added over a period of 3 h.The internal temperature has to be maintained at 80 °C during the whole reaction. After ail monomer emulsion has been added, the batches are heated at 80 °C for another 30 min.Then, the flasks are allowed to cool to room temperature. Now the reaction mixtures are adjusted to pH 8.5 by addition of 5% NaOH solution. 

A standard apparatus (250 ml, three-neck round-bottom flask, thermometer, heating bath) is equipped with magnetic stirrer, reflux condenser, dropping funnel with pressure release, and one neck is sealed with a septum which can be used for thermometer inlet but also addition of initiator solution using a syringe the apparatus is flushed with argon. Under argon atmosphere one adds 8.3 g of a 30-wt% polyvinylalcohol aqueous solution (2.5 g of PVA, molar mass about 30,000 g/mol), 1/5 of the vinylpyrrolidone amount (4.5 g),and about 3 drops of the initiator. 

JIS K 3602 (1990) Japanese Industrial Standard Apparatus for the estimation of biochemical oxygen demand (BODj) with microbial sensor... 

Refractive Index, 1.563-0.001 at 25° can be determined using an Abbe refractometer or other standard apparatus... 

The so-called bubble point of a membrane - a measure ofthe membrane pore size - can be determined by using standard apparatus. When determining the bubble point of small, disk-shaped membrane samples (47 mm in diameter), the membrane is supported from above by a screen. The disk is then flooded with a liquid, so that a pool of liquid is left on top. Air is then slowly introduced from below, and the pressure increased in a stepwise manner. When the first steady stream of bubbles to emerge from the membrane is observed, that pressure is termed the bubble point. ... 

The principal drawbacks of the standard apparatus is that it is difficult to flush efficiently and liquid transfer operations are awkward. With little additional complexity, the apparatus can be adapted for efficient purging and solution transfer by syringe or cannula. 

Fire point the lowest temperature at which, under specified conditions in standardized apparatus, a petroleum product rapidly vaporizes sufficiently to form above its surface an air-vapor mixture which bums continuously when ignited by a small flame. 

Most Cone Calorimeters include instrumentation for measuring light extinction in the exhaust duct, using a laser light source, described in ASTM E 1354 and ISO 5660-2 (Section 14.3.5.3.2). Instrumentation to measure concentrations of soot, carbon dioxide, carbon monoxide, and other gases are commonly added. Some laboratories have used a modified version of the standard apparatus to conduct studies in vitiated or oxygen enriched atmospheres.43 50... 

In order to ensure comparability, it is possible to advance in one of two directions either to use perfectly standard apparatus of a type possessed by all, or to calibrate one s home-made apparatus by use of a standard or reference catalyst available to all. There is much to be said in favor of the former approach, but it implies the use of commercially available equipment, which is unlikely to be cheap and is not yet widely employed. However, experience teaches that there is little difficulty in reproducing measurements concerning the physical properties of catalytic materials (XPS, XRD, TEM, etc.) when, as is usually the case, standard instrumental methods are used. The alternative is to accept that for some time to come many laboratories will continue to use home-made facilities for chemisorption and catalysis, and that there will therefore be a need for a number of standard catalysts that may be tested to ensure the proper functioning of the equipment (and of the operator ). 

The following contribution compU recently published cyclizations. Most of these examples have not been included in our former survey on the dilution principle [3 a] and are thought as a continuation and update of that former survey up to 1990. As shown there, some characteristic experimental standard methods are specified here as well. (For a standard apparatus and a modified motor-driven syringe-type version see [3d, e].)... 

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