Hach DR/850 Procedures Manual page 384

PHOSPHORUS, TOTAL,
Sample Disposal Information
Summary of Method
REQUIRED REAGENTS
Total Phosphorus Test 'N Tube Reagent Set ......................................50 tests ............. 27426-45
Includes: (1) 272-42, (1) 20847-66, (1) 21060-46, (1) 27430-42, (50) Acid Dilution Vials*
Description
PhosVer 3 Phosphate Reagent Powder Pillows ..................1 ..............50/pkg ............. 21060-46
Potassium Persulfate powder Pillows .................................1 ..............50/pkg ............. 20847-66
Sodium Hydroxide Solution, 1.54 N ........................... 2 mL ............ 100 mL ............. 27430-42
Test 'N Tube Acid Dilution Vials .......................................1 ..............50/pkg
Water, deionized for reagent blank .............................. 5 mL ............ 100 mL ................. 272-42
REQUIRED APPARATUS
COD/TNT Adapter .............................................................1 ..................each ............. 48464-00
DRB 200 Reactor, 110 V, 15 x 16 mm tubes .................................................. LTV082.53.40001
DRB 200 Reactor, 220 V, 15 x 16 mm tubes.................................................. LTV082.52.40001
Funnel, micro ......................................................................1 ..................each ............. 25843-35
Test Tube Rack ............................................................... 1-3 ..................each ............. 18641-00
Pipet, TenSette, 1 to 10 mL.................................................1 ..................each ............. 19700-10
Pipet Tips, for 19700-10 TenSette Pipet ..................... varies ..............50/pkg ............. 21997-96
* These items are not sold separately.
continued
Final samples will contain molybdenum. In addition, final
samples will have a pH less than 2 and are considered corrosive
(D002) by the Federal RCRA.
Phosphates present in organic and condensed inorganic forms
(meta-, pyro- or other polyphosphates) must be converted to
reactive orthophosphate before analysis. Pretreatment of the
sample with acid and heat provides the conditions for hydrolysis
of the condensed inorganic forms. Organic phosphates are
converted to orthophosphate by heating with acid and persulfate.
Orthophosphate reacts with molybdate in an acid medium to
produce a phosphomolybdate complex. Ascorbic acid then
reduces the complex, giving an intense molybdenum blue color.
384
Quantity Required
Per Test Unit Cat. No.
.................................. *