Environmental Express SimpleDist - Manual (Page 18)

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SimpleDist: Operation and Instruction Manual System Operation
3.0 Interferences
3.1 Cyanate, which may be encountered in certain industrial effluents, will hydrolyze to some extent even at the pH of 9.5 at
which distillation is carried out.
3.2 Residual chlorine must be removed by pre-treatment of the sample with sodium thiosulfate or other reagents before
distillation.
4.0 Chemicals Required: Distillation Only
4.1 Ammonia-free water
4.2 Borate buffer solution
4.3 Sodium hydroxide, 1N
4.4 Boric acid catch solution (20g/L) – for use with the nesslerization and titration methods
4.5 Sulfuric acid catch solution, 0.04N – for use with the phenate and ion selective electrode methods
4.6 Sodium thiosulfate (for dechlorinating)
Note: The toxicity for each of the reagents used in this procedure is not fully documented. Treat each chemical as a potential health
hazard and limit exposure. Exercise good laboratory technique with an emphasis on safety.
Ammonia Nitrogen Distillation with the SimpleDist™ Continued:
5.0 Procedure
5.1 Adjust an aliquot of at least 25mL of sample to a pH of 9.5 using 1N sodium hydroxide and remove any residual
chlorine.
5.2 Pipette 25mL of pH-adjusted sample or an aliquot diluted to 25mL with reagent water into the SimpleDist TM System
boiling tube. For solids weigh 1.0g +/- 0.01g and dilute to 25mL. Add boiling chips to the boiling tube.
5.3 Insert the inlet part liner into the green screw cap and thread assembly onto the top of the boiling tube.
5.4 Assemble inlet tube with funnel tip and insert into the smaller port on cap.
5.5 Pipette 15 - 20mL of the proper catch solution into the collection trap. If using the Snip & Pour concentrate pour the
entire 5mL of the 0.2N H
2
SO
4
into the trap and add enough DI Water to bring the volume up to a 22-23mL. Attach the
collection trap to the boiling tube and attach the tubing/adaptor from the vacuum manifold to the collection trap.
5.6 Repeat steps 5.1 through 5.5 for all samples to be distilled.
5.7 Turn on the vacuum and adjust each valve to provide an air flow bubble rate of 10-15 bubbles per second for each
position as viewed in the collection trap. Vacuum should be sufficient to maintain slight negative pressure on the
assembly throughout the distillation.
Important: Monitor the vacuum to insure a back pressure does not build up in the boiling tube!
5.8 Add 1.25mL of borate buffer to the sample through the reagent inlet tube.
5.9 Turn the heat on and set the temperature of the HotBlock
TM to 135ºC. The block will achieve this temperature in
approximately 30 minutes. Heat for an additional 60 minutes after the block achieves this temperature.
5.10 Remove the collection trap from the assembly.
Important: Vacuum must remain on!
5.11 Turn air/vacuum valves to the off position.
5.12 Bring the volume of distillate in the collection trap up to the 25mL mark with the appropriate catch solution.
5.13 The distillate in the collection trap is now ready for analysis. Pour contents into an appropriate container. When
pouring, position the vent tube of the collection trap up to prevent trapping of air.
5.14 After use clean exterior surfaces with a damp sponge. For acid spills sponge with a diluted solution of sodium
bicarbonate followed by distilled water.
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