QC 8000 REAGENT RECIPES
GEL Revision Date:
3 August 2004
Index
Alkalinity (Methyl Orange)……………………………………………………………..3
Ammonia………………………………………………………………………………….4
Bromide…………………………………………………………………………………..8
Chloride………………………………………………………………………….……...10
Nitrate/Nitrite……………………………………………………………………..…….11
Orthophosphate…………….…………………………………………………………..13
Sulfate…………………………………………………………………………………...16
Sulfate (Low flow)……………………………………………………………………....19
Total Nitrogen…………………………………………………………………………..22
Total Phosphate………………………………………………………………………....25
General Notes:
1. GEL revisions are indicated by italics.
2. For different quantities, the respective amounts are given in parentheses or brackets.
3. Use Nanopure deionized water (>M ohm-cm) for all solutions specifying water as solvent.
4. Degassing with helium:
To prevent bubble formation, degas water before preparing solutions with helium. Use He at 140 kPa (20 lb/in2) through a helium degassing tube (Lachat Part No. 50100). Bubble He through the water for several minutes.
5. Chemical and reagent locations:
DCDry Chemical Cabinet (GWC 675)
SCStandards Cabinet (GWC 675)
WIRWalk-in Refrigerator (GWC 675)
ACAcid Cabinet (GWC 675)
BCBase Cabinet (GWC 675)
OC Organic Solvent Cabinet (GWC 675)
RCReagent Cabinet (GWC 637)
QuickChem® METHOD 10-303-31-1-A
DETERMINATION OF ALKALINITY (METHYL ORANGE) IN SURFACE AND WASTEWATERS BY FLOW INJECTION ANALYSIS
COLORIMETRY
21 December 1998
List of Raw Materials
Hydrochloric Acid (HCl) – CAS 7647-01-0, (DC 675)
Methyl Orange (indicator grade, Aldrich #11,451-0) – CAS #, (DC 675)
Potassium Acid Phthalate [Potassium Hydrogen Phthalate, Potassium biphthalate, KHP], (HOOCC6, H4COOK) – CAS 877-24-7, (DC 675)
Carbon dioxide-free water
Bring 6 L of water to a boil for five minutes to remove carbon dioxide. Cool before using to avoid error in the volumetric measurements.
Reagent 1. Hydrochloric Acid (HCl), 0.1M
By Volume: In a 1 L volumetric flask containing about 800 mL carbon dioxide-free water, add 8.3 mL concentrated hydrochloric acid. Dilute to the mark with carbon-dioxide free water. Invert to mix.
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Reagent 2. KHP Buffer pH 3.1, 25.0 mM(RC 637)
By Volume: In a 1 L container, dissolve 5.0 g potassium acid phthalate [potassium hydrogen phthalate, potassium biphlalate, KHP, (HOOCC6 H4COOK)] in 900 mL carbon dioxide-free water. Add 85.0 mL 0.1 M HCl (reagent 1), then add acid (no more than 5.0 mL) to bring the pH to 3.1 +/- 0.05. If greater then 5.0 mL of 0.1 M HCl is necessary, start over in the preparation of this reagent. If this fails, use Standardized 0.1 M HCl. Pour into a glass storage bottle. Prepare fresh weekly.
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Reagent 3. Methyl Orange Reagent(RC 637)
By Volume: In a 1 L volumetric flask, dissolve 0.1313 g methyl orange (indicator grade, Aldrich #11,451-0) in about 700 mL carbon dioxide-free water. Dilute to the mark and invert to mix. Store in glass. Use indicator grade methyl orange.
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QuickChem Method 10-107-06-1-J
DETERMINATION OF AMMONIA BY FLOW INJECTION ANALYSIS
15 March 2001
List of Raw Materials
Disodium Ethylenediamine Tetraacetic Acid (Na2EDTA) - CAS 6381-92-6, (DC)
Phenol (C6H5OH), crystalline – CAS 108-95-2, (WIR)
Sodium Hydroxide (NaOH) – CAS 1310-73-2, (BC)
Sodium Hypochlorite (NaOCl), Commercial grade; e.g. Clorox institutional & germicidal, (WIR)
Sodium Nitroprusside [Sodium Nitroferricyanide] (Na2Fe(CN)5NO·2H2O) –
CAS 13755-38-9, (DC)
Sulfuric Acid (H2SO4) – CAS 7664-93-9, (DC)
Reagent 1. Sodium Phenolate(RC 637)
*Add Phenol last. (Use also for TRAACS) Add NaOH to a portion of the H2O and allow to cool. Use the remainder of H2O to rinse in phenol.
CAUTION: Wear gloves. Phenol causes severe burns and is rapidly absorbed into the body through the skin.
By Volume: In a 1 (0.5) [0.25] L volumetric flask, dissolve 83 (41.5) [20.75]g crystalline phenol (C6H5OH) is approximately 600 (300) [150]mL DI water. While stirring, slowly add 32 (16) [8]g sodium hydroxide (NaOH). Cool, dilute to the mark and invert to mix. Do not degas this reagent. Prepare fresh every 3 to 5 days. Discard when reagent turns brown. *Use solid NaOH for N determination in base cabinet.
By Weight: QC 8000-Good Baseline. To a tared 1(0.5) L container, add 888 (444) g DI water. Add 83 (41.5) g crystalline phenol (C6H5OH). While stirring, slowly add 32(16) g sodium hydroxide (NaOH). Cool and invert to mix thoroughly. Do not degas this reagent. Prepare fresh every 3 to 5 days. Discard when reagent turns brown. *Use solid NaOH for N determination in base cabinet.
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Reagent 2. Sodium Hypochlorite *Use 30 mL Clorox/70mL water
By Volume: In a 500 mL volumetric flask, dilute 214 mL 5.25% sodium hypochlorite (NaOCl) to the mark with DI water. Invert to mix. Prepare fresh daily.
*@ 3% sodium hypochlorite use 175 mL bleach and 25 mL water.
*Use small bottle of bleach on counter in walk in – old JT Baker bottle. Refill it from large bleach bottle under sink in walk in.
* 70 ml of water to 30 mL of bleach – WJR 10/7/02
By Weight: To a tared 500 mL container add 214 g 5.25% sodium hypochlorite (NaOCl) and 250 g DI water. Stir or shake to mix. Prepare fresh daily.
Note: If Clorox bleach is not available solid sodium hypochlorite can be substituted. Dilute 26.25 g sodium hypochlorite to 500 mL with DI water.
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Reagent 3. Sodium Nitroprusside(RC 637)
By Volume: In a 1(0.5) L volumetric flask, dissolve 0.5(0.25) g sodium nitroprusside (sodium nitroferricyanide [Na2Fe(CN)5NO·2H2O]). Dilute to the mark with DI water and invert to mix. Store in a light resistant container. Prepare fresh every 1 to 2 weeks.
By Weight: To a tared 1 L container add 0.5 g sodium nitroprusside (sodium nitroferricyanide [Na2Fe(CN)5NO·2H2O]) and 1000 g DI water. Invert to mix. Store in a light resistant container. Prepare fresh every 1 to 2 weeks.
* Use TrAAcs concentration 0.5g in 1L
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Reagent 4. 1 M Sodium Hydroxide Solution
By Volume: In a 1 L volumetric flask, dissolve 40.0 g sodium hydroxide (NaOH) in approximately 900 mL DI water. Dilute to the mark and mix with a magnetic stirrer until dissolved. *Use solid NaOH for N determination in base cabinet.
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Reagent 5. Buffer for Non Acid Preserved Samples(RC 637)
By Volume: In a 1(0.5) L volumetric flask, dissolve 50.0 (25)g disodium ethylenediamine tetraacetic acid (Na2EDTA) and 225 (117.5) mL 1 M sodium hydroxide (Reagent 4) (or 15 mL 15 M NaOH or use 9 g solid NaOH*) in approximately 700 (350) mL DI water. Dilute to the mark and mix with a magnetic stirrer until dissolved. Prepare fresh monthly.
* Use the NaOH in base cabinet for nitrogen determination (9 (4.5) g is for prep of 1 (0.5) L of buffer). --CK 03/01/01
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If the samples are preserved at a pH less than two with sulfuric acid, the following reagent and standard recipe changes apply:
Reagent 6. Buffer for Acid Preserved Samples(RC 637)
By Volume: In a 1 L volumetric flask, dissolve 50.0 g disodium ethylenediamine tetraacetic acid (Na2EDTA) and 254 mL 1 M sodium hydroxide (NaOH) solution (Reagent 4) [10.16 g solid NaOH for 1 L or 5.08 g for 500 mL] in approximately 700 mL DI water. Dilute to the mark and mix with a magnetic stirrer until dissolved. Prepare fresh monthly.
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Reagent 7. Sulfuric Acid Diluent for Carrier and Standards (Acid preserved samples only)
By Volume: In a 1 L volumetric flask, add approximately 800 mL DI water followed by 2 mL concentrated sulfuric acid. Dilute to the mark. Keep flask sealed when not in use with parafilm to avoid ambient ammonia contamination.
NOTES: ______
QuickChem Method 10-135-21-2-A
DETERMINATION OF BROMIDE IN WATERS BY FLOW INJECTION ANALYSIS
List of Raw Materials
Acetic Acid (glacial) – CAS 64-19-7, (AC 675)
Chloramine-T – CAS 7080-50-4, (DC 675)
Phenol Red – CAS 143-74-8, (DC 675)
Sodium Acetate – CAS 127-09-3, (DC 675)
PREPARATIONS OF REAGENTS
Use deionized water (10 megohm) for all solutions
Degassing with helium:
To prevent bubble formation, degas all solutions except the standards with helium. Use He at 140 kPa (20 lb/in2) through a helium degassing tube (Lachat Part No. 50100). Bubble He through the solution for one minute.
Reagent 1. Chloramine-T Color Reagent
By Volume: In a 1 (0.5) [0.25] L volumetric flask, add 0.80 (0.40) [0.20] g chloramine-T. Add water to the mark. Invert flask six times. Inversion will dissolve the chloramine-T. Do not use a magnetic stirrer. Prepare fresh daily.
By Weight: To a tared 1 (0.5) [0.25] L container, add 0.80 (0.40) [0.20] g chloramine-T and 999 (499.5) [249.75] g water. Invert the container six times. Inversion will dissolve the chloramine-T. Do not use a magnetic stirrer. Prepare fresh daily. NOTE: Dry chloramine-T reagent is good for 6 months.
Reagent 2. Phenol Red Color and Buffer Reagent
By Volume: In a 1 (0.5) [0.25] L volumetric flask, add approximately 600 mL water. Add 29.0 (14.5) [7.25] mL glacial acetic acid. Swirl contents of flask. Add 41.0 (20.5) [10.25] g sodium acetate. Swirl contents until dissolved. Add 0.040g (0.020) [0.010] phenol red (water soluble). Swirl contents until dissolved. Add water to the mark. Mix with a magnetic stirrer.
By Weight: To a tared 1 L (0.5) [0.25]container, add 929 (464.5) [232.25] g water and 30.0 (15.0) [7.5] g glacial acetic acid. Swirl contents of container. Add 41.0 (20.5) [10.25] g sodium acetate. Swirl contents of container until dissolved. Add 0.040 (0.020) [0.010] g phenol red (water soluble). Mix with a magnetic stirrer.
Reagent 3. Amberlite XAD-2 Column Preparation
- Prepare approximately 1.0 g Amberlite XAD-2 resin, 20-60 mesh, by mixing with 10 mL water to make a slurry.
- Remove one end fitting from the glass column (Lachat Part No. 50232). Clamp the column vertically to a ring stand with the open end of the column facing upward. Attach a small plastic funnel to the top of the column with Tygon tubing. Attach a six inch piece of Tygon tubing to the nozzle of a 10.0 mL plastic syringe and attach the other end of Tygon tubing to the bottom of the column. Fill the column with water. Pour the Amberlite resin slurry into the plastic funnel. Slowly draw back on the plastic syringe in order to draw the water and Amberlite resin into the glass column. Avoid trapping air bubbles in the column or its fittings.
- When the resin has settled, replace the end fitting. To ensure a good seal, remove any resin particles from the threads of the glass, the column end, and the end fitting. To store the column, join the ends of the Teflon tubing with a union.
NOTES: ______
QuikChem® METHOD 10-117-07-01-H
QuikChem® METHOD 10-117-07-01-I
DETERMINATION OF CHLORIDE BY FLOW INJECTION ANALYSIS COLORIMETRY
All Ranges
13 December 1994
List of Raw Materials
Ferric Nitrate (Fe(NO3)3·9H2O) – CAS 7782-61-8, (DC 675)
Mercuric Thiocyanate (Hg(SCN)2) – CAS 592-85-8, (DC 675)
Methanol (CH3OH) – CAS 67-56-1, (OC 675)
Reagent 1. Combined Color Reagent
- Stock Mercuric Thiocyanate Solution(Use also for TRAACS)(RC 637)
In a 1 (0.25) L volumetric flask, dissolve 4.17 (1.042) g mercuric thiocyanate (Hg(SCN)2) to about 500(125) mL methanol. Dilute to the mark with methanol and mix.
CAUTION: Mercuric thiocyanate is toxic. Wear gloves!
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- Stock Ferric Nitrate Reagent, 0.5 M(Use also for TRAACS) (RC 637)
In a 1 L volumetric flask, dissolve 202 g ferric nitrate (Fe(NO3)3·9H2O) in approximately 800 mL water. Add 25 mL 65% concentrated nitric acid and dilute to the mark. Invert to mix.
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- Combined Color Reagent (Use also for TRAACS)(RC 637)
In a 500 mL volumetric flask, add 75 mL stock mercuric thiocyanate solution with 75 mL stock ferric nitrate reagent and dilute to the mark with water. Invert to mix. Vacuum filter through a 0.45 micrometer membrane filter.
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QuikChem® METHOD 10-107-04-1-C
QuikChem® METHOD 10-107-04-1-O
DETERMINATION OF NITRATE/NITRITE IN SURFACE AND WASTEWATERS BY FLOW INJECTION ANALYSIS
All Ranges
23 April 1999
List of Raw Materials
Ammonium Chloride (NH4Cl) – CAS 12125-02-9, (DC 675)
Ammonium Hydroxide (NH4OH) – CAS 1336-21-6, (BC 675)
Disodium EthyleneDiamine Tetraacetic Acid (Na2EDTA) – CAS 6381-92-6, (DC 675)
Hydrochloric Acid (HCl) – CAS 7647-01-0, (AC 675)
N-(1-naphthyl)ethylenediamine dihydrochloride (NED)–CAS 1465-25-4, (DC 675)
Phosphoric Acid (H3PO4) – CAS 7664-38-2, (AC 675)
Sodium Hydroxide (NaOH) – CAS 1310-73-2, (BC 675)
Sulfanilamide – CAS 63-74-1, (DC 675)
Reagent 1. 15 N Sodium Hydroxide
By Volume: Add 150g NaOH very slowly to 250 ml or g of water. CAUTION: The solution will get very hot! Swirl until dissolved. Cool and store in a plastic bottle.
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Reagent 2. Ammonium Chloride buffer, pH 8.5(hood 637)
By Volume: CAUTION: Fumes!!! In a hood, to a 1(0.5) L volumetric flask, add 500(250) mL water, 105(52.5) mL concentrated hydrochloric acid (HCl), 95 (47.5)mL ammonium hydroxide (NH4OH), and 1.0 (0.5) g disodium EDTA. Dissolve and dilute to the mark. Invert to mix. Adjust the pH to 8.5 with HCl or 15 N NaOH solution.
By Volume x2: 1000 mL H2O
210 mL HCl
100 mL rinse H2O
190 mL NH4OH
100 mL rinse H2O
1600 mL
400 mL H2O (Add 2 g EDTA to this solution)
2000 mL NH4Cl Buffer
By Weight: CAUTION: Fumes!!! In a hood, to a tared 1 L container, add 800 g water, 126 g concentrated hydrochloric acid (HCl), 85 g ammonium hydroxide (NH4OH) and 1.0 g disodium EDTA. Stir until dissolved. Adjust the pH to 8.5 with HCl or 15 N NaOH.
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Reagent 3. Sulfanilamide color reagent(RC 637)
By Volume: To a 1(0.5 L) L volumetric flask, add about 600(300) mL water. Then add 100 (50) mL of 85% phosphoric acid (H3PO4), 40.0(20) g sulfanilamide and 1.0(0.5) g N-(1-naphthylenediamine dihydrochloride (NED). Shake to wet and stir for 30 minutes to dissolve. Dilute to the mark and invert to mix. Store in a dark bottle. This solution is stable for one month.
By Weight: To a tared, dark 1 L container, add 876 g water, 170 g 85% phosphoric acid (H3PO4), 40.0 g sulfanilamide and 1.0 g N-(1-naphthyl)ethylenediamine dihydrochloride (NED). Shake until wetted and stir with stir bar for 30 minutes until dissolved. This solution is stable for one month.
NOTES: ______
QuikChem® METHOD 10-115-01-1-Q
QuikChem® METHOD 10-115-01-1-A
DETERMINATION OF ORTHOPHOSPHATE IN WATERS BY FLOW INJECTION ANALYSIS COLORIMETRY
All Ranges
28 December 1998
List of Raw Materials
Ammonium Molybdate Tetrahydrate [(NH4)6Mo7O24·4H2O] – CAS 12054-85-2, (DC 675)
Antimony Potassium Tartrate [Potassium Antimonyl Tartrate Hemihydrate] (K(SbO)C4H4O6·1/2H2O) – CAS #, (DC 675)
Antimony Potassium Tartrate [Potassium Antimonyl Tartrate Trihydrate] (K(SbO)C4H4O6·3H2O) – CAS #, (DC 675)
Ascorbic Acid (Spectrum catalog no. AS 102), granular – CAS 50-81-7, (DC 675)
Dodecyl Sulfate, Sodium Salt (CH3(CH2)11OSO3Na) – CAS 151-21-3, (DC 675)
Sodium Hydroxide (NaOH) – CAS 1310-73-2, (BC 675)
Sulfuric Acid (H2SO4) – CAS 7664-93-9, (AC 675)
Tetrasodium Ethylenediamine tetraacetic Acid (Na4EDTA) – CAS #, (DC 675)
Reagent 1. Stock Ammonium Molybdate Solution(RC 637)
By Volume: In a 1 L volumetric flask dissolve 40.0 g ammonium molybdate tetrahydrate [(NH4)6Mo7O24·4H2O] in approximately 800 mL water. Dilute to the mark and stir for two hours. Store in plastic and refrigerate. May be stored up to two months when kept refrigerated.
By Weight: To a tared 1 L container add 40.0 g ammonium molybdate tetrahydrate [(NH4)6Mo7O24·4H2O] and 983 g water. Stir for two hours. Store in plastic and refrigerate. May be stored up to two months when kept refrigerated.
______
Reagent 2. Stock Antimony Potassium Tartrate Solution
By Volume: In a 1 L volumetric flask, dissolve 3.0 antimony potassium tartrate (potassium antimonyl tartrate hemihydrate K(SbO)C4H4O6·1/2H2O) or dissolve 3.22 g antimony potassium tartrate (potassium antimonyl tartrate trihydrate K(SbO)C4H4O6·3H2O) in approximately 800 mL of water. Dilute to the mark and stir for a minimum of four hours. Store in a dark bottle and refrigerate. May be stored up to two months when kept refrigerated.
By Weight: To a 1 L dark, tared container add 3.0 g antimony potassium tartrate (potassium antimonyl tartrate hemihydrate K(SbO)C4H4O6·1/2H2O) or dissolve 3.22 g antimony potassium tartrate (potassium antimonyl tartrate trihydrate K(SbO)C4H4O6·1/2H2O) and 995 g of water. Stir for a minimum of four hours. Store in a dark bottle and refrigerate. May be stored up to two months when kept refrigerated.
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Reagent 3. Molybdate Color Reagent
By Volume: To a 250 (500)[1000] mL volumetric flask add about 125 (250)[500] mL water, then add 8.75 (17.5)[35] mL concentrated sulfuric acid (CAUTION: The solution will get very hot!). Swirl to mix. When it can be comfortably handled, add 18 (36)[72] mL Stock Antimony Potassium Tartrate Solution (Reagent 2) and 53.25 (106.5)[213] mL Stock Ammonium Molybdate Solution (Reagent 1). Dilute to the mark and invert three times. Prepare fresh weekly.
By Weight: To a tared 1 L container add 680 g water, then 64.4 g concentrated sulfuric acid (CAUTION: The solution will get very hot!). Swirl to mix. When it can be comfortably handled, add 72.0 g Stock Antimony Potassium Tartrate Solution (Reagent 2) and 213 g Stock Ammonium Molybdate Solution (Reagent 1). Prepare fresh weekly.
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Reagent 4. Ascorbic Acid Reducing Solution, 0.33 M
By Volume: In a 1 (0.5)[0.25] L volumetric flask dissolve 70 (35)[17.5]g granular ascorbic acid (Spectrum catalog no. AS 102) in about 700 (350)[175]mL of water. Dilute to the mark and invert to mix. Add 1.0 (0.5)[0.25] g dodecyl sulfate, sodium salt (CH3(CH2)11OSO3Na) (Aldrich catalog no. 86,210-0). Prepare fresh weekly. Discard if the solution becomes yellow. Do not use ascorbic acid powder.
By Weight: To a tared 1 L container, add 60.0 g granular ascorbic acid (Spectrum catalog As102) and 975 g water. Stir or shake until dissolved. Add 1.0 g dodecyl sulfate, sodium salt (CH3(CH2)11OSO3Na) (Aldrich catalog no. 86,210-0). Prepare fresh weekly. Discard if the solution becomes yellow. Do not use ascorbic acid powder.
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Reagent 5. Sodium Hydroxide – EDTA Manifold Rinse
Dissolve 65 g sodium hydroxide (NaOH) and 6 g tetrasodium ethylenediamine tetraacetic acid (Na4EDTA) in 1.0 L or 1.0 kg water. Store in plastic.
NOTES: ______
QuikChem® METHOD 10-116-10-2-B
DETERMINATION OF HIGH RANGE SULFATE BY FLOW INJECTION ANALYSIS COLORIMETRY
23 October 2000
List of Raw Materials
Ammonium Chloride (NH4Cl) – CAS 12125-02-9, (DC 675)
Ammonium Hydroxide (NH4OH)– CAS 1336-21-6, (BC 675)
Barium Chloride Dehydrate (BaCl2·2H2O)– CAS #, ( )
Ethanol (CH5OH)– CAS #, ( )
Hydrochloric Acid (HCl)– CAS 7647-01-0, (AC 675)
methylthymol blue {3,3’-bis[N,N-di(carboxymethyl)aminomethyl]-thymol-sulfonephthalein, pentasodium salt} (Lachat Part no. 50243, see System Note 11.3.4)– CAS #, (DC 675)
Sodium Hydroxide (NaOH)– CAS 1310-73-2, (BC 675)
Tetrasodium EDTA Dehydrate (Na4EDTA)– CAS #, ( )
Reagent 1. Carrier, 0.30 mg SO42-/L(RC 637)
By Volume: To a 1 L volumetric flask add 0.30 mL of 1000 mg/L Stock Sulfate Solution (Standard 1, found in Standards Preparations section). Dilute to the mark and mix by inverting. Degas with helium.
By Weight: To a tared 1 L container add 0.30 g of 1000 mg/L Stock Sulfate Solution (Standard 1, found in Standards Preparation section) and 999.7 g water. Shake or stir to mix. Degas with helium.
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Reagent 2. Barium Chloride Solution, 6.24 mM(RC 637)
By Volume: In a 1 L volumetric flask, dissolve 1.526 g barium chloride dehydrate (BaCl2·2H2O) and 500 mL water. Shake or stir until dissolved. Degas with helium.
By Weight: In a 1 L volumetric flask, dissolve 1.526 g barium chloride dehydrate (BaCl2·2H2O) and 995 g water. Shake or stir until dissolved. Degas with helium.
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Reagent 3. Hydrochloric Acid, 1.0 M
By Volume: In a 1 L volumetric flask add approximately 800 mL water and 83 mL concentrated hydrochloric acid (specific gravity 1.20, 37%). CAUTION: Fumes! Dilute to the mark and mix by inverting. Degas with helium.
By Weight: To a tared 1 L container add 913 g water and 99.6 g concentrated hydrochloric acid (specific gravity 1.20, 37%). CAUTION: Fumes! Shake or stir to mix well. Degas with helium.
______
Reagent 4. Barium – MTB Color Reagent Make at least 1 Day Before Run
Note: In preparing this reagent, we have found that the purity of the methylthymol blue and the denaturants in the alcohol are critical. USE THE SOURCES SPECIFIED BELOW, or test the material from alternate sources for suitability before using.
By Volume: Into a dry 500 (1000) mL volumetric flask place 0.236 (0.472) g methylthymol blue {3,3’-bis[N,N-di(carboxymethyl)aminomethyl]-thymol-sulfonephthalein, pentasodium salt} (Lachat Part no. 50243, see System Note 11.3.4). Add 50 (100)mL Barium Chloride Solution (Reagent 2) which may be used to aid in the transfer of the dye. Swirl to dissolve. Using a 5 mL Mohr pipet or a 4.0 mL volumetric pipet, add 4.0 (8.0) mL of the 1.0 M Hydrochloric Acid Solution (Reagent 3) and mix. The solution should turn orange. Add 71 (142) mL water and dilute to the mark with ethanol (ethyl alcohol, specially denatured anhydrous alcohol, Aldrich 24,511-9). Mix by inverting. The pH of this solution should be 2.5. Prepare this solution the day before use and store it refrigerated in a brown plastic bottle. Allow to warm to room temperature before using, then degas with helium. This is good for one week.
By Weight: To a tared 500 mL dry brown plastic bottle, place 0.236 g methylthymol blue {3,3’-bis[N,N-di(carboxymethyl)aminomethyl]-thymol-sulfonephthalein, pentasodium salt}(Lachat Part no. 50243, see System Note 11.3.4). Add 50 g Barium Chloride Solution (Reagent 2) which may be used to aid in the transfer of the dye. Swirl to dissolve. Add 4.0 g of the 1.0 M Hydrochloric Acid Solution (Reagent 3) and mix. The solution should turn orange. Add 71 g water and 321 g ethanol (ethyl alcohol, specially denatured anhydrous alcohol, Aldrich 24,511-9). Stir or shake to mix well. The pH of this solution should be 2.5. Prepare this solution the day before use and store it refrigerated in a brown plastic bottle. Allow to warm to room temperature before using, then degas with helium.