Analytical Flow Solution Recipes

Follow all lab safety protocols when handling chemicals, including protective eye and skin wear and appropriate lab clothing.

Ammonium Reagents

Citrate Complexing Reagent (2L)

<ul>
	<li>Sodium Citrate 63g</li>
	<li>Sodium Hydroxide 2 g</li>
	<li>Nanopure Water</li>
	<li>Brij 35 (30%)</li>
</ul><h5>Partially fill a 2.0 L volumetric flask with nanopure water. Add dry chemicals, stir until dissolved then bring to volume with nanopure water. Filter reagent and store at room temperature or refrigerate for up to 6 weeks.  To prepare working reagent add 5 ml Brij 35 / 1 liter of solution.  Prepare working reagent fresh daily.</h5>

Alkaline Phenol (500 ml)

<ul>
	<li>Sodium Hydroxide (10N or 40% w/v) 40 ml</li>
	<li>Liquid Phenol (88%) 47 ml</li>
	<li>Nanopure Water</li>
</ul><h5>Partially fill a 500 ml volumetric flask with nanopure water. Place in ice bath and stir while slowly adding sodium hydroxide first, then liquid phenol. Dilute to volume with nanopure water and filter. Store refrigerated in light resistant container.  This reagent should be made as needed and not stored more than 3 days.</h5>

NOTE: This reagent is hazardous waste! Any glassware, paper towels, gloves, filter paper, etc used/contaminated during this process must be treated or disposed of as hazardous waste.

Sodium Nitroferricyanide (1L)

<ul>
	<li>Sodium Nitroferricyanide 0.5 g</li>
</ul>
<ul>
	<li>Nanopure Water</li>
</ul><h5>Partially fill a 1.0 L volumetric flask with nanopure water. Carefully measure sodium nitroferricyanide and add to nanopure water. Dilute to volume with nanopure water and filter. Store refrigerated in light resistant container for up to 4 weeks.</h5>

NOTE: This reagent is hazardous waste! Any glassware, paper towels, gloves, filter paper, etc used/contaminated during this process must be treated or disposed of as hazardous waste.

Nitrate/Nitrite Reagents

Ammonium Chloride EDTA Buffer (4L)

<ul>
	<li>Ammonium Chloride 340 g</li>
	<li><span class="caps">EDTA</span> 0.4 g</li>
	<li>10N Sodium Hydroxide 20+ ml</li>
	<li>Nanopure Water</li>
	<li>Brij 35 (30%)</li>
</ul><h5>Partially fill a 4L Erlenmeyer flask with nanopure water. Add ammonium chloride and <span class="caps">EDTA</span> and stir until dissolved. Adjust buffer solution using 10 N sodium hydroxide (start with 20 ml and add from there as needed) to pH 8.50. Dilute to volume with nanopure water and filter. Store refrigerated for up to 6 weeks.  To prepare working reagent add 4 ml Brij 35 / L of solution.  Prepare working reagent fresh daily.</h5>

NOTE: Always keep some of the buffer available that does not have Brij 35 added to it. This is used when reactivating the cadmium reduction coil.

Color Reagent (1L)

<ul>
	<li>Phosphoric Acid (85%) 100 ml</li>
	<li>Sulfanilamide 40 g</li>
	<li>N-1-Naphthylethylenediamine dihydrochloride 2g</li>
	<li>Nanopure Water 1 L</li>
</ul><h5>Partially fill a 1 L volumetric flask with nanopure water. On stir plate, add phosphoric acid then dry chemicals. Stir until dry chemicals are dissolved. This can take several hours of stirring. Bring to volume with nanopure water and filter.  Store refrigerated in light resistant container for up to 2 months.</h5>

Cadmium Coil Activation/Recharge Reagents

(see page 17 of The Flow Solution Nitrate/Nitrite Methodology for procedure)

<ul>
	<li>Nanopure Water</li>
	<li>0.5 N Hydrochloric Acid</li>
	<li>2% Copper Sulfate</li>
	<li>Ammonium Chloride <span class="caps">EDTA</span> Buffer (no Brij 35)</li>
</ul><h4>0.5 N Hydrochloric Acid (100 ml)</h4>

<ul>
	<li>Hydrochloric Acid (37%) 4.9 ml</li>
	<li>Nanopure Water to 100 ml</li>
</ul><h5>Partially fill a 100 ml volumetric flask with nanopure water. While stirring (and in the hood), slowly add the hydrochloric acid. Bring to volume (1L) with nanopure water.</h5>

2% Copper Sulfate (1L)

<ul>
	<li>Copper Sulfate 2 g</li>
	<li>Nanopure Water 100 ml</li>
</ul><h5>Partially fill a 100 ml volumetric flask with nanopure water. Add copper sulfate and stir until dissolved. Bring to volume with nanopure water.</h5>

Super Cartridge Cleaning Solutions

If there are problems with contamination in the cartridges the following solutions may be used to clean the interior and related tubing. It is not necessary to disconnect plumbing to do this.

<ul>
	<li>1 N Sodium Hydroxide</li>
	<li>1 N Hydrochloric Acid</li>
</ul><h4>1 N Sodium Hydroxide (1 L)</h4>

<ul>
	<li>10 N Sodium Hydroxide 100 ml</li>
	<li>Nanopure Water</li>
</ul><h5>Partially fill a 1.0 ml volumetric flask with nanopure water. While stirring (and in the hood), slowly add the sodium hydroxide. Bring to volume with nanopure water.</h5>

1 N Hydrochloric Acid ( 1 L)

<ul>
	<li>Hydrochloric Acid (37%) 82.5 ml</li>
	<li>Nanopure Water</li>
</ul><h5>Partially fill a 1.0 L volumetric flask with nanopure water. While stirring (and in the hood), slowly add the hydrochloric acid. Bring to volume with nanopure water.</h5>

The Nitrate/Nitrite cartridge can be cleaned as follows:

1. Pump a solution of 1 ml Brij / 1 L nanopure water through lines for at least 1/2 hour.
2. Pump 1 N Hydrochloric acid solution for 1/2 hour.
3. Brij/water solution for 1/2 hour
4. 1 N sodium hydroxide solution for 1/2 hour
5. Brij/water solution for 1/2 hour

The Ammonium channel may be cleaned in the same manner but reverse the order of solutions:

1. brij/water
2. 1 N NaOH solution
3. brij/water
4. 1 N HCl solution
5. brij/water

*NOTE: It is EXTREMELY important to rinse with brij/water solutions between the acid and base solutions!