Environmental Express SimpleDist - Page 12

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SimpleDist® Micro Heating Block: Operation & Instruction Manual Distillation Methods
Ammonia Nitrogen Distillation with the
SimpleDist® Micro Heating Block
4.4 Sulfuric acid trapping solution (0.024M) - Add approximately 500 mL reagent water to
a 1000 mL volumetric ask. Add 24 mL 1.0 N sulfuric acid and swirl to mix.
Caution: This reaction is exothermic and has the potential to generate fumes. Use caution.
When the solution is at ambient temperature, add reagent water to bring the solution
up to the 1000 mL mark on the ask.
4.5 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.
5.0 Procedure
5.1 Set the temperature of the heating block to 120°C and allow the heat to stabilize. This
should take approximately 30 minutes. If all reagents are ready to use this should be
sufcient time to set up and prepare a full batch of 20 samples and all necessary QC.
5.2 Place one collector tube for each sample, standard, QC, or other aliquot needing to be
distilled in a test tube rack with the “Measure” end up. Add 1.0 mL of 0.024 M H
2
SO
4
solution (4.4) or 2 mL 0.13 M boric acid solution (Step 4.3) to each tube. The solution to
choose will depend upon the requirements of the analytical method. Note: After nal
distillate dilution this will give a concentration of 0.04 N H
2
SO
4
or boric acid. The initial
concentration may be adjusted to provide alternate nal concentrations as needed by
the analytical method of choice. Cap the tubes with one membrane and cap. Ensure
that the membrane is not torn and shows a visible edge all the way around the tube.
5.3 Place one sample tube for each sample, standard, QC, or other aliquot needing to be
distilled in a test tube rack and add 6.0 mL of sample/standard to each tube. The tubes
may be labeled with permanent ink to aid in sample identication. Do not add any
label to the tube as this will interfere with the t in the block as well as heat transfer
during the distillation process. If solid samples are being distilled, add 0.5 to 1.0 g of
the sample to the tube along with approximately 5 mL of reagent water. Samples high
in organic content such as sludge should tend toward the lower sample mass while
samples that are relatively free of organic material can use the higher end.
5.4 If the sample has been previously preserved with acid, add 1.0 mL of the borate
buffer for preserved samples (Step 4.2.2) to the rst sample tube. If the sample has
not been previously preserved with acid instead add 0.75 mL of the borate buffer for
unpreserved samples (Step 4.2.1). Immediately place the ‘Distill’ end of a lled and
capped collector tube (Step 5.2) over the open end of the sample tube. Press the two
pieces together to form a rough t. You will not be able to hand press a tight seal.