• pH meter, balance (1/10 000), 0.45 pm filter paper, funnel, flask (1000 mL), pipette, 5 mm x 100 mm glass column, spectral gamma analyser or gamma counter (well-type detector is recommended).

• No. 717 anion exchange resin (Beijing Analytical Reagent Factory), HCl (A. R.), Na2CO3 (A. R.).

111.4.2. Analytical procedure

The analytical procedure is shown in Fig. 92.

111.4.3. Recommendations

It is recommended that a reference solution (sample with known tracer concentration in the brine of the target reservoir) should be prepared and applied in an actual scale test in order to obtain very reliable results through use of the above analytical procedures. The concentration of the tracer in the reference solution should be at a similar level to that in the samples collected from the field.