Quantitative transfer of liquids

Quantitative Transfer of Liquid to a Volumetric Flask Insert a funnel into the neck of the volumetrie flask use a stirring rod to direct the flow of liquid from the beaker into the funnel. With the stirring rod, tip off the last drop of liquid on the spout of the beaker. Rinse both the stirring rod and the interior of the beaker with distilled water and transfer the washings to the volumetric flask, as before. Repeat the rinsing process at least two more times. 

Practical biochemistry is highly reliant on analytical methods. Many analytical techniques must be mastered, but few are as important as the quantitative transfer of solutions. Some type of pipet will almost always be used in liquid transfer. Since students may not be familiar with the many types of pipets and the proper techniques in pipetting, this instruction is included here. 

In comparison with syringe techniques, the use of cannulae provides better air exclusion and greater convenience for the transfer of large volumes of solution. However, syringe techniques are much better suited for the quantitative dispensing of liquids, as demonstrated in the following example. 

A. Liquid Nitrogen and Liquid Air. Liquid nitrogen is the most commonly used refrigerant for the manipulation of condensable materials on a vacuum system because it is easy to use, inexpensive, and will not support combustion. Furthermore, its boiling point is low enough, — 196°C (77°K), to lower the vapor pressure of most materials below 10 3 torr, which is necessary for the quantitative transfer of condensible materials on the vacuum system. 

C. Camci, K. Kim, and S. A. Hippensteele, A New Hue Capturing Technique for the Quantitative Interpretation of Liquid Crystal Images Used in Convective Heat Transfer Studies, ASME J. of Turbomachinery, 114, pp. 512-518,1992. 

Qualitative and, hopefully, quantitative estimates of how the process result will be measured must be made in advance. The evaluations must allow one to estabhsh the importance of the different steps in a process, such as gas-liquid mass transfer, chemical reac tion rate, or heat transfer. 

Supercritical fluid extraction (SFE) and Solid Phase Extraction (SPE) are excellent alternatives to traditional extraction methods, with both being used independently for clean-up and/or analyte concentration prior to chromatographic analysis. While SFE has been demonstrated to be an excellent method for extracting organic compounds from solid matrices such as soil and food (36, 37), SPE has been mainly used for diluted liquid samples such as water, biological fluids and samples obtained after-liquid-liquid extraction on solid matrices (38, 39). The coupling of these two techniques (SPE-SFE) turns out to be an interesting method for the quantitative transfer... 

As a result of Eq. (11) we are able to calculate the chemical potential of any molecule X in any liquid system S, relative to the chemical potential in a conductor, i.e. at the North Pole. Hence, COSMO-RS provides us with a vehicle that allows us to bring any molecule from its Uquid state island to the North Pole and from there to any other liquid state, e.g. to aqueous solution. Thus, given a liquid, or a reasonable estimate of AGjis of a soUd, COSMO-RS is able to predict the solubility of the compound in any solvent, not only in water. The accuracy of the predicted AG of transfer of molecules between different Uquid states is roughly 0.3 log units (RMSE) [19, 22] with the exception of amine systems, for which larger errors occur [16, 19]. Quantitative comparisons with other methods will be presented later in this article. 

---