Worldwide Open Proficiency Test: Determination of ... - Nucleus - IAEA
Worldwide Open Proficiency Test: Determination of ... - Nucleus - IAEA
Worldwide Open Proficiency Test: Determination of ... - Nucleus - IAEA
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In such a case, the analyst has to revise the analytical procedure to assure a complete<br />
separation <strong>of</strong> Ra.<br />
Equally successful determinations using GS and RCP were reported only for Pb-210. The<br />
applied RCP was based on the separation <strong>of</strong> Pb-210 after the addition <strong>of</strong> a stable carrier<br />
according to the method <strong>of</strong> chromate precipitation followed by lead chloride precipitation,<br />
then mixing the source with scintillation cocktail and performing the measurement using a<br />
Liquid Scintillation Spectrometer.<br />
[Bq/kg]<br />
15<br />
13<br />
11<br />
9<br />
7<br />
5<br />
3<br />
1<br />
74<br />
131<br />
225<br />
172<br />
145<br />
21<br />
259<br />
86<br />
77<br />
130<br />
128<br />
87<br />
156<br />
110<br />
17<br />
160<br />
73<br />
257<br />
5<br />
59<br />
70<br />
175<br />
7<br />
194<br />
166<br />
39<br />
88<br />
207<br />
90<br />
134<br />
163<br />
65<br />
251<br />
236<br />
133<br />
82<br />
56<br />
62<br />
63<br />
171<br />
188<br />
52<br />
192<br />
193<br />
51<br />
152<br />
61<br />
213<br />
237<br />
212<br />
96<br />
200<br />
214<br />
151<br />
79<br />
114<br />
150<br />
184<br />
95<br />
244<br />
265<br />
83<br />
41<br />
185<br />
26<br />
276<br />
261<br />
32<br />
252<br />
245<br />
264<br />
143<br />
34<br />
13<br />
30<br />
36<br />
138<br />
125<br />
263<br />
Draft, page 36<br />
Sr-90 in moss-soil<br />
Laboratory code<br />
Figure 23: S-shape presentation <strong>of</strong> the Sr-90 results, the majority <strong>of</strong> unacceptable results is due to<br />
overestimation <strong>of</strong> the Sr-90 massic activity<br />
For Pu-238, 52% <strong>of</strong> reported results were not acceptable. Many laboratories failed in proper<br />
implementation <strong>of</strong> the procedure which resulted in not acceptable results, the exact technical<br />
reason for the shortcoming should be investigated. Little information was reported in the<br />
questionnaire on the chemical recovery correction. The main reason for unacceptable results<br />
could be attributed but not limited to a non validated radiochemical procedure, inappropriate<br />
control <strong>of</strong> the method blank, matrix reference or spiked materials were not used to verify the<br />
correctness <strong>of</strong> the application <strong>of</strong> the RCP and/or inappropriate quality control mechanism.
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