Working with radioactivity

pH electrodes are available in many different configurations. What is essential is that the H+-permeable glass envelope is fully immersed in the solution. 

Likewise, it is essential that surface pH electrodes are in complete contact with the surface being measured. 

Recently, ion sensitive field effect transistors have become available for pH measurements they appear to be very sensitive and can be used with very small volumes (a few pi). 

In contrast to pH measurements, conductivity measurements are not widely used in the biochemistry laboratory, despite their undoubted importance. The reason for this is not clear, since the necessary apparatus and electrodes are no more expensive than those needed to measure pH, and the measurements are rapid and straightforward. Conductivity can be used readily to determine the ionic strength of solutions. 

---

Table 11.6 General control measures for work with radioactive substances...

When specifically labelled compounds are required, direct chemical synthesis may be necessary. The standard techniques of preparative chemistry are used, suitably modified for small-scale work with radioactive materials. The starting material is tritium gas which can be obtained at greater than 98% isotopic abundance. Tritiated water can be made either by catalytic oxidation over palladium or by reduction of a metal oxide ... 

Chemical advances frequently are driven by technology. The discovery that atoms have inner structure was an outgrowth of the technology for working with radioactive materials. In Chapter 2 we describe a famous experiment in which the structure of atoms was studied by bombarding a thin gold foil with subatomic particles. A contemporary example is the use of lasers to study the details of chemical reactions. We introduce these ideas in Chapters 7 and 8. 

Unlike his boss, Rutherford was a skilled experimentalist. His apparatuses were usually jury-rigged and crude, but they got the job done. His work with the particles and rays spontaneously emitted by radioactive elements led him to conclude that their emissions came in two forms. With admirable simplicity, Rutherford named them for the first two letters in the Greek alphabet, alpha and beta. After Cambridge, Rutherford accepted physics professorships at universities in Canada and Manchester, England, J.J. Thomsons hometown. He continued to work with radioactive... 

The first person to identify the hydrogen ion as a component of all atoms was Ernest Rutherford. Rutherford had his hand in virtually every aspect of atomic research. By 1919, he had discovered alpha and beta rays, found a new element (radon), won a Nobel Prize for his work with radioactive elements, and demonstrated that atoms had nuclei. For good measure, in 1914, he was knighted. However, still more discoveries and honors awaited him. 

The following operations should be done using standard safety procedures for working with radioactive compounds. All steps involving SASD prior to initiation of the photoreaction should be done protected from light to avoid loss of phenyl azide activity. The radiolabeling procedure should be done quickly to prevent excessive loss of NHS ester activity due to hydrolysis. 

Prize in 1962.) Madame Curie died from radiation poisoning that resulted from her work with radioactive elements. 

It is a common experience when working with radioactive materials that a sample under investigation contains two or more radioisotopes. Assume that you have a sample with just two radioisotopes, one with a half-life about 10 times that of the other. The amounts of the two in the sample are too small to separate chemically. 

Years of working with radioactive elements in the lab left Marie and Pierre Curie very sick as well. In 1934, Marie Curie died of a blood disease caused by exposure to radiation. When scientists examined her lab notebooks many decades later, they uncovered her glowing and toxic fingerprints everywhere. 

WORKING WITH RADIOACTIVE MATERIALS Generally Accepted Practices... 

When we put in a hard day s work, we want to be assured that we aren t being exposed to any unnecessary risks. Let s face it, at the end of our shift we all want to return safely to our homes in good health. Those working with radioactive materials therefore need to follow a few simple guidelines to help protect themselves from potential dangers. First and foremost, we must have a healthy respect for radioactive materials and radiation. Note that respect is different than fear. This respect will ensure that we do not get careless or complacent in our day-to-day activities. Secondly, we must maintain our exposure to radioactive materials in accordance with the ALARA principle. That is, we must maintain our exposure as low as reasonably achievable. Thirdly, three words will help enforce the... 

ALARA principle time, distance, and shielding. We should minimize our time working with radioactive materials, maximize the distance between us and the source of radiation, and use proper shielding to minimize our exposure. Finally, we must make sure that we understand and follow all the facility procedures and regulations regarding the use of radioactive materials so that our safety and that of our patients are assured. 

Working with Radioactivity Rules, Practices and Safety Precautions... 

Perform experiments with volatile materials or radioactive gases in a well-ventilated fume hood rated for that class of work. Good practice for safety purposes is to conduct most work with radioactive materials in a fume hood. 

To ensure that people working with radioactive materials are protected from the harmful effects of radiation, they wear photographic badges. These are developed periodically and the greater the exposure to radiation, the greater the fogging . When the value becomes too high, the worker is taken off the work task. 

Operational Radiation Protection The fundamentals of operational radiation protection (i.e., how to proceed when working with radioactive products) are based on three factors distance, time, and shielding. In any case, it is obvious that the radiation hazard is increased with the activity of the radiation source, as can be derived from the mathematical equation to calculate the exposure rate X given by... 

One of the most common topics asked of those who work with the actinides relates to handling procedures. The radioactive nature of these elements does require the use of special facilities, processes, and precautions. However, working with radioactive elements in subcritical quantities is as safe, if not safer, than handling many of the toxic chemicals found in a typical synthetic laboratory. The primary advantage in handling radioactive material is the ease with which these elements can be detected. Unlike other toxic chemicals, for example, lead, thallium, arsenic, and so on, a simple survey (seconds) with a radiation detector will show if containment of the material has been lost, where it is, and approximately how much is present. With appropriate monitoring, virtually no uptake of radioactive material occurs, and if any personnel contamination does occur, it is quickly detected and treated. 

With respect to practical work with radioactive substances, the risk of a hazardous effect should be as low as possible, and <0.1%. The following measures are recommended to keep radiation exposure to a minimum ... 

---