Technique of Laboratory Work

Voskresencky, P. I. Tekhnika laboratornykh robot (Technique of Laboratory Work) (Moscow Khimiya, 1970). 

Due to poor laboratory technique, statistically determined limits may be inadequately wide. For example, recovery limits of zero to 200 percent are not acceptable for any analyte, even if determined statistically they indicate only a poor quality of laboratory work. Such control limits should not satisfy a data user who is concerned with data quality. 

An introduction to the current techniques and methods of analytical and preparative biochemistry. In addition to the core methodologies of sample preparation, separation and analysis, the authors discuss the application of immunological and biophysical approaches to the study of biochemical systems, as well as advising on biochemical literature, equipment and safety aspects of laboratory work. 

Comment. Because literature service is required in two plants some distance apart, this administrator had little time for on-the-job training of new employees. He has, however, formulated ideas of what he is looking for and translated his ideas into specific educational qualifications. These he has learned are minimum essentials. As there is little uniformity of concept in relation to education of literature chemists, these ideas constitute a real contribution. A chemist himself, in no way did he decry the importance of laboratory work, but he did emphasize the fact that literature work requires a different type of person -- one who approaches it with the conviction of its importance as a distinct occupation. He has also been willing to admit his unsuccessful attempt in selling a career to those who offered skepticism and resistance. On the other hand, there have been instances where a person wholly unfamiliar with literature work may like it, once he realizes he is a creative member of the research function. In fact, the situation next described shows results wherein the selling technique paid dividends. 

Surveys have shown (Section 1.2) that many laboratories appear to be unaware of the poor quality of the results which they may be producing. Full awareness of the potential sources of error in the various aspects of laboratory work is undoubtedly the best stimulus to maintaining a high standard of accuracy and precision, and clinical chemistry laboratories should have their quality control data continuously available and under review. Control techniques have come into general use only comparatively recently, and their value may not yet be appreciated widely enough by the heads of laboratories. 

TLC has become an important technique in laboratory work, because it permits the rapid determination of the composition of complex mixtures. TLC allows the isolation of substances in micro amounts. If, however, milligrams or even grams of substance are required, CC has to be applied, as TLC would involve a high cost and excessive time. In many cases, even the so-called thick layer or prep layer is but a poor choice because of time, cost, and sometimes inadequate transferability of the parameters of the analytical technique. In addition, the transfer from TLC to CC, however, often proves to be difficult because the CC adsorbent is not usually analogous to the TLC adsorbent. 

Of all the experimental means for determining the above density or distribution functions direct measurement of I(t) or of W(t) is preferred as inherently the most accurate. The former is not practically feasible in chemical engineering but is practiced in biomedicine. Direct determination of both F(t) and W(t) is an attractive technique in laboratory work but... 

I view this text as a guide and reference, a sort of road map to biomedical safety. Learning proper safety principles and techniques at the onset of laboratory work is a great advantage to students just embarking on research careers, as it will lead to the development of safe habits in research work. Safety education is also essential for the research technician starting to work at an industrial biomedical laboratory. Finally, even experienced workers will find this book useful, as it serves as a reminder of unsafe practices. I sincerely hope that this text will help you to learn more about laboratory safety and to make your lab a safer place to work. 

A basic knowledge of calorimetric and Fourier transform infrared (FTIR) and ultraviolet (UV) spectrometric techniques, and of laboratory work, is required before starting with the experiments in solution. Gas-phase measurements of BF3 affinity and lithium cation basicity must be carried out by chemists experienced in gas/liquid calorimetric techniques and mass spectrometric techniques, respectively. 

It is regretted that the size of the volume has rendered the insertion of literature references impossible the Selected Bibliography (A,5) may partly compensate for this omission. Section numbers are now included in the headings of the pages—a feature introduced in response to requests by many readers. The volume comprises virtually at least three books under one cover, viz., experimental technique, preparations, and qualitative organic analysis. It should therefore continue to be of value as a one volume reference work in the laboratory. Students at all levels will find their requirements for laboratory work (excluding quantitative organic analysis) adequately provided for and, furthermore, the writer hopes that the book will be used as a source of information to supplement their theoretical studies. 

Microwave spectroscopy is used for studyiag free radicals and ia gas analysis (30). Much laboratory work has been devoted to molecules of astrophysical iaterest (31). The technique is highly sensitive 10 mole may suffice for a spectmm. At microwave resolution, frequencies are so specific that a single line can unambiguously identify a component of a gas mixture. Tabulations of microwave transitions are available (32,33). Remote atmospheric sensing (34) is illustrated by the analysis of trace CIO, O, HO2, HCN, and N2O at the part per trillion level ia the stratosphere, usiag a ground-based millimeter-wave superheterodyne receiver at 260—280 GH2 (35). 

The enormous increase in the number of groups working in this domain, in concert with the advances in the fundamental techniques of chromatography and laboratory automation (screening technologies) have led to the rapid and unprecedented accumulation of data [1]. 

Some preliminary laboratory work is in order, if the information is not otherwise known. First, we ask what the time scale of the reaction is surely our approach will be different if the reaction reaches completion in 10 ms, 10 s, 10 min, or 10 h. Then, one must consider what quantitative analytical techniques can be used to monitor it progress. Sometimes individual samples, either withdrawn aliquots or individual ampoules, are taken. More often a nondestructive analysis is performed, the progress of the reaction being monitored continuously or intermittently by a technique such as ultraviolet-visible spectrophotometry or nuclear magnetic resonance. The fact that both reactants and products might contribute to the instrument reading will not prove to be a problem, as explained in the next chapter. 

It is perhaps an indication of the limited success of electrophoretic techniques for the determination of pesticide residues at trace levels that although many papers and reviews on the subject have been published, very few laboratories involved in the routine analysis of residues rely on such techniques for their work. Electrophoretic techniques have suffered because of poor flexibility and sensitivities compared with chromatographic techniques. 

---