The development of sample pre-treatment and extraction methods for the detection of cobalt in soil using a tungsten (W)-coil atomic emission spectrometer (AES)

The development of sample pre-treatment and extraction methods for the detection of cobalt in soil using a tungsten (W)-coil atomic emission spectrometer (AES)

Radioactive substances -- Detection

Soils -- Cobalt content -- Measurement

Lawrence, Kelly Ann

2008

Salido, Arthur

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Terrorism has become a prominent security threat in modem society. The International Atomic Energy Agency (IAEA) has identified radioactive sources used in industrial radiography, radiotherapy, irradiators, and thermo-electric generators as the most readily available source of radioactive materials to terrorists. In response to this security threat, a fast response detection system is required in order to immediately reduce the atmosphere of public hysteria in the event these chemicals are released via a radioactive dispersion device or ""dirty bomb."" A Tungsten (W) - coil Atomic Emission Spectrometer (AES) is being developed for the detection of radionuclides. Because typical samples are complex (like soil), sample pre-treatment methods may be needed in order to enhance the detectability of the elements of interest (Co, Cs, Ir, c, r. Tc, and Yb). The research presented here focuses on methods for the extraction of Cobalt (Co2+) from soil, including the use of chelating agents (Na-DDTC and APDC) and solid-phase extraction (SPE). The IC-Chelate SPE cartridges proved to be the most effective method for the extraction of Co2 + from soil and in the presence of competing metal ions, resulting in an average Co2+ percent recovery of 99.27% � 11 .90 for the extracted soil samples. The precipitation of Co2+ using the chelating agents APDC and Na-DDTC, while useful for the extraction of Co2+ from soil and in the presence of competing metal ions, were not as effective the IC-Chelate SPE cartridges. Average percent recovery values from soil for Co2+ of 64.14% � 2.46 and 62.44% � 7.66 were obtained using the APDC and Na-DDTC chelating agents respectively. The SCX SPE cartridges did not prove to be an effective method for the recovery of Co2+ from soil as the average percent recovery of the tested soil samples was only 7.14 % � 0.81. The field method for the recovery of Co2 + from spiked soil which was shaken with 5 % nitric acid and extracted using syringe IC-Chelate SPE cartridges was an effective method. An average Co2+ percent recovery of 58.19 % � 2.25 was obtained for the tested soil samples. The method is also valuable in a qualitative sense where the goal is to simply determine the presence of cobalt in the environment.

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