Determination of Uranium in Urine using EIChrom Resins

transcript

EIChrom User Group Meeting 15/11/99

Helen E Carter Loughborough University UK

Arthur E Lally OBE RTC Ltd UK

Michaela Langer EIChrom Europe France

Peter Warwick Loughborough University UK

2RTCEIChrom User Group Meeting 15/11/99

Evaluation of some methods

Reason for the study

Inconsistency in results from certain methods

Attribute possible causes

Problem areas? A satisfactory analytical

result requires

Combination of

Analyst Method Equipment

Instrumentation Laboratory environment Materials and chemicals

Analyst

Trained limited experience

Limited time to test effectiveness

Manual procedures

Analytical

Methodology

For this study all were similar

Method A no apparent problems

Method B inconsistencies in results

Method C less of a problem than B

Method D small inconsistencies

Equipment

Materials EIChrom resin TRU

Batch to batch variation

Storage

Study protocol Part 1

PhD student - initial work

Familiarisation with techniques using Synthetic urine Genuine urine Co-precipitation Electro deposition

Actual methods

Study protocolPart 2

Evaluation of data

PhD student finished her work and left

Final tests on hydrolysis to be carried out

Conclusions to be made

Outline -Method A

Mineralisation with HNO3

Copptn on Ca phosphate Muffle at 900Oc 8 hrs Dissolution HNO3+ Al nitrate Reduction with Fe(II) sulphate TRU resin column Elution with Amm. Oxalate Source preparation Reduction with TiCl3 Micro pptn on CeF3

Outline –Method B

Mineralise with HNO3/H2O2

Muffle at 500oc 6 hrs Hydrolyse 1.4 M HNO3

Copptn Ca phosphate Ferrous sulphate/ Al2(NO3)3

TRU resin U elution Micro pptn with LaF3

Outline-Method C

Similar to method B but Muffle 12hrs at 500oC Separation on AGMP1

resin Pu on column U in load + 8M HNO3

wash U fraction on to TRU resin As for method B

Outline-Method D

Mineralisation and evaporation on hotplate

Hotplate to 500oC 5hrs Dissolution / hydrolysis in

2M HNO3

Co pptn Ca phosphate Dissolution HCl Co pptn Fe phosphate As per method C

Results - same batch of resin

Method A, Mock Urine Batch TR8B resin CeF3 pptn % recovery 84, 75, 77, 94, 88, 92, 89, 95, 92, 87, 93, 77,

Results – DifferentBatches of Resin

TR6D 88%

TR6D 91%

TR6D 62%

TR7A 88%

TR7A 55%

TR8C 70%

TR8C 23%*

TR8C 86%

*blocked col.

Results using different methods

B1 45%

B2 36%

B3 32%

C1 93%

C2 88%

C3 99%

D1 76%

D2 76%

D3 74%

Results- Different methods (real urine)

A1 78%

A2 71%

A3 76%

B1 28%

B2 30%

B3 28%

C1 67%

C2 Lost in anal.

C3 68%

Conclusions – to date

Consistency for Method A and analyst satisfactory

Different batches of resin No real evidence of

effect

Different methods A, C and D reasonable B poor

What is going on? Analyst or method !

Method A always OK Method B always poor

Give the analyst a chance!

What else could be wrong?

HYDROLYSIS ?

HydrolysisAlways been a problem

Actinides U and Pu love pyrophosphates better than any ion-exchange resin

(yes even EIChrom!) Experiment with

hydrolysis procedures New analyst on job Old analyst in years!!

Hydrolysis proceduresevaluated using:-

Mock Urine Method B CeF3 micro pptn U-233 spike

Very large prayer mat.

Method B amendments 1

Samples 1 and 2 Standard 500oC 6hrs Standard 1.4M nitric

hydrolysis and Fe(II) SO4

Samples 3 and 4 As above but 500oC 18hrs

Method Bamendments 2

Samples 5 and 6

Standard 500oC 6hrs Standard 1.4M nitric but-

with ferrous sulphamate and Fe(II) SO4

Samples 7 and 8

As above but 500oC 18hrs

Results of hydrolysischanges to Method B

Ferrous sulphate

1 6hrs 81%

2 6hrs 82%

3 15hrs 78%

4 15hrs 79%Ferrous sulphamate

5 6hrs 72%

6 6hrs 70%

7 15hrs 80%

8 15hrs 70%

Conclusions of hydrolysis changes

No significant differences

Method B appears to give good results

Overall Conclusions

The resin appears to make no difference with regards to Age Batch Packing

Methods all appear OK at times

What about the operator? Think about method,

operator and equipment combination!

Summary of all experiments

No effect of resin All methods satisfactory

Human factor Bored staff? Staff in wrong method?

Automation

Who wants an old chemist?

Determination of Uranium in Urine using EIChrom Resins

Documents