Calibration of volumes

The static methods arc volumetric or gravimetric. The volumetric method involves the use of a vacuum system comprising two sections, a dosing section which allows the introduction of accurately measured quantities of the adsorbate, and a sample section which contains the catalyst. The precision of the volumetric method depends on accurate calibrations of volumes. 

Some remarks are made about the conception and the automation of volumetric devices for the determination of gets adsorption isotherms. The calibration problems discussed concern a procedure to check the manometer linearity the optimal pressure ratio for the calibration of volumes by gas expansion measurements of He adsorption in zeolites minimal measurable surface area. The possibility of readily setting experimentai points in a prescribed zone of the isotherm by using operating iines is discussed, and ruies for the extrapolation of the isotherms are suggested for some cases a modified BET equation for adsorption in micro/mesoporous solids, and a relation between the saturation volume and the capillary condensation pressure. 

The general list of factors influencing the uncertainty in the gross rock volume included the shape of structure, dip of flanks, position of bounding faults, position of internal faults, and depth of fluid contacts (in this case the OWC). In the above example, the owe is penetrated by two wells, and the dip of the structure can be determined from the measurements made in the wells which in turn will allow calibration of fhe 3D seismic. 

Table 9.1), with the choice of buret determined by the demands of the analysis. The accuracy obtainable with a buret can be improved by calibrating it over several intermediate ranges of volumes using the same method described in Chapter 5 for calibrating pipets. In this manner, the volume of titrant delivered can be corrected for any variations in the buret s internal diameter. 

Schwartz has published some hypothetical data for the titration of a 1.02 X ICr" M solution of a monoprotic weak acid (pXa = 8.16) with 1.004 X ICr M NaOH. " A 50-mL pipet is used to transfer a portion of the weak acid solution to the titration vessel. Calibration of the pipet, however, shows that it delivers a volume of only 49.94 ml. Prepare normal, first-derivative, second-derivative, and Gran plot titration curves for these data, and determine the equivalence point for each. How do these equivalence points compare with the expected equivalence point Comment on the utility of each titration curve for the analysis of very dilute solutions of very weak acids. 

Switch on and allow the instrument to warm up the time for this will be quite short if the circuit is of the solid-state type. While this is taking place, make certain that the requisite buffer solutions for calibration of the meter are available, and if necessary prepare any required solutions this is most conveniently done by dissolving an appropriate buffer tablet (these are obtainable from many suppliers of pH meters and from laboratory supply houses) in the specified volume of distilled water. 

For most purposes it is not necessary to follow the procedures given above for the preparation of standard buffer solutions the buffer tablets which are available from laboratory suppliers, when dissolved in the specified volume of distilled (de-ionised) water, produce buffer solutions suitable for the calibration of pH meters. 

Self-Tfst 6.4B A calorimeter was calibrated by mixing two aqueous solutions together, each of volume 0.100 L. The heat output of the reaction that took place was known to be 4.16 kj, and the temperature of the calorimeter rose by 3.24°C. 

Unrecognized shifts in the calibration of the columns will affect the raw data, which are in terms of elution time of the components of the specimen from the chromatographic columns. Use of log hydrodynamic volume allows the operator to correct for such... 

The results of environmental monitoring exercises will be influenced by a variety of variables including the objectives of the study, the sampling regime, the technical methods adopted, the calibre of staff involved, etc. Detailed advice about sampling protocols (e.g. where and when to sample, the volume and number of samples to collect, the use of replicates, controls, statistical interpretation of data, etc.) and of individual analytical techniques are beyond the scope of this book. Some basic considerations include the following, with examples of application for employee exposure and incident investigation. 

This glass apparatus is inexpensive and consists of a bottle having an internal sampling tube and calibrated sampling volume (5 ml). One draws a sample and then expels it into an external 5 ml beaker. 

Vi = portion of volume of VEnd injected into the GC or HPLC system ( uL) Wa = amount of fluthiacet-methyl for Vi read from calibration curve (ng)... 

The molecular weight distributions were determined only in terms of the polystyrene equivalent from the polystyrene calibration of the GPC columns. This can only be regarded as semiquantitative, as the method determines only the relative hydrodynamic volumes. If the polysilane chain was significantly stiffer than polystyrene, the molecular weights would be estimated too high. If the chains are... 

Mercury porosimetry is based on the fact that mercury behaves as a nonwetting liquid toward most substances and will not penetrate the solid unless pressure is applied. To measure the porosity, the sample is sealed in a sample holder that is tapered to a calibrated stem. The sample holder and stem are then filled with mercury and subjected to increasing pressures to force the mercury into the pores of the material. The amount of mercury in the calibrated stem decreases during this step, and the change in volume is recorded. A curve of volume versus pressure represents the volume penetrated into the sample at a given pressure. The intrusion pressure is then related to the pore size using the Washburn equation... 

The gas pycnometer is based on the ideal gas law. A known quantity of gas (characterized by a determined temperature and pressure) is allowed to flow from a calibrated reference volume into a calibrated sample cell containing the solid. A second pressure reading is obtained, and the sample volume is calculated. 

V = (1000 0.4) ml (from supplier s catalogue), iq (V) = 0.10 ml (standard deviation of replicate measurements of volume of liquid in flask when filled to the calibration mark). 

Pressurized sample infusion An easily calibrated, low volume pumping system for ESI-MS analysis of reactions... 

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