LECTURE 2: Three Grades of Water

1. distilled water

2. deionized water

3. RO water

THREE GRADES OF REAGENT WATER:

DISTILLED WATER

Water solely purified by distillation results

DEIONIZED WATER

Water purified by ion exchange produces

RO WATER

Reverse osmosis, which pumps water across a semipermeable membrane, produces

• ultrafiltration

• ultraviolet light

• sterilization

• ozone treatment.

Water can also be purified by:

1. Distillation

2. Ion exchange

3. Reverse osmosis

4. UV oxidation

Processes involved in the preparation of reagent grade water:

specifications needed for its use

Laboratory requirements generally call for reagent grade water that, according to the Clinical and Laboratory Standards Institute (CLSI), is classified into one of six categories based on the______ rather than the method of purification or preparation.

• clinical laboratory reagent water (CLRW)

• special reagent water (SRW)

• instrument feed water

• water supplied by method manufacturer

• autoclave and wash water

• commercially bottled purified water

Categories based on the specifications needed for its use:

• type I

A long-held convention for categorizing water purity was based on three types, I to III,

• with ____ water having the most stringent requirements and generally suitable for routine laboratory use.

TYPE I REAGENT WATER

Used for procedures that require maximum water purity for accuracy and precision.

TYPE I REAGENT WATER

Used for ultramicrochemical analyses, measurements of nanogram or subnanogram concentrations, tissue or cell methods (microscopy) and preparation of standard solutions.

TYPE I REAGENT WATER

Uses:

• flame photometry,

• AAS,

• blood gases and pH,

• enzyme studies,

• electrolyte testing,

• HPLC,

• trace metal and

• iron studies.

TYPE II REAGENT WATER

For hematology, microbiology, immunology and chemistry section.

• hematology

• microbiology

• immunology

• chemistry

What sections of the laboratory is Type II Reagent Water?

TYPE II REAGENT WATER

Acceptable for preparation of reagents and quality control materials.

TYPE III REAGENT WATER

For urinalysis, parasitology and histology

• urinalysis

• parasitology

• histology

What sections of the laboratory is Type III Reagent Water?

TYPE III REAGENT WATER

For washing glassware