Hach DR/850, Procedures Manual, Page: 55 / 460

55
SAMPLE PRETREATMENT
, continued
General Digesdahl Digestion (Not USEPA accepted)
Many samples may be digested using the Digesdahl Digestion Apparatus
(Cat. No. 23130). It is designed to digest many types of samples such as
oils, wastewater, sludges, feeds, grains, plating baths, food, and soils. In
this procedure the sample is oxidized by a mixture of sulfuric acid and
hydrogen peroxide. Digestion of a dry sample requires less than ten
minutes, while liquid samples require about 1 minute/mL. The digestion
is done in a special flat-bottomed 100-mL volumetric flask. Aliquots
(sample portions) are taken for analysis using colorimetric methods.
Procedures for digestion and using the Digesdahl Digestion Apparatus are
based on the type and form of the sample, and are found in the Digesdahl
Digestion Apparatus Instruction Manual, which is included with each
Digesdahl Digestion Apparatus.
Distillation
Distillation is an effective way of separating chemical components for
analysis. The Hach Distillation Apparatus (see
Figure 12 ) is adapted
easily for many test needs and is suitable for water and wastewater
samples. Sample distillations are easy and safe to perform.
Applications for the General Purpose Distillation Apparatus include:
Arsenic and cyanide require special glassware sets in addition to the
General Purpose Set (the Arsenic Distillation Apparatus and the Cyanide
Distillation Apparatus). All connecting glassware is manufactured with
threaded connectors for ease and safety. The General Purpose Heater
provides efficient heating and the Support Apparatus anchors the glassware.
•
fluoride
•
phenols
•
albuminoid nitrogen
•
selenium
•
ammonia nitrogen
•
volatile acids