Volumetric Flasks

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Introduction

A Volumetric Flask is a pear-shaped lab apparatus with a round flat bottom commonly used for dilutions and preparing standard solutions. In 1892, the world's first volumetric flask was invented by Dewar after his name, “Dewar Flask.”

The volumetric flask, also known as measuring flask or graduated flask, is lightweight, compact, and chemical resistant. The flask has ring graduation marking on its extended neck, which stipulates the liquid volume when filled up to the meniscus. The ridge of the flask has a PE Stopper to prevent spillage and maintain a required temperature for the chemicals. 

Need of a Volumetric Flask 

• Difficult to measure accurate volumes of liquid materials. 
• Faults in mass measurements. 
• Not feasible in preparing high precision drugs and medicines. 

Classes of a Volumetric Flask 

There are two classes in which a volumetric flask is manufactured - Class A and Class B. 

The Class A volumetric flasks have the highest level of accuracy with tighter tolerance limits. They have a unique serial number for traceability. The graduation mark on the flask is accurately placed on the flask. The highest accuracy Class A volumetric flasks have a blue color print for clear glass and white for amber variants. The Class A flasks are individually calibrated with their certification. 

The Class B volumetric flasks are used for general purpose and calibrated to a lower level of accuracy. The flasks under Class B have white print on them. Class B flasks lack calibration. These volumetric flasks are generally used in schools.

Standards under which the volumetric flask is manufactured 

The volumetric flask is manufactured under three standards, namely : 

• ASTM (American Society for Testing and Materials) 
• ISO (International Organization for Standardization) 
• USP (United Standard Pharmacopeia). 

Glassco is the first-ever glassware manufacturing plant in India to produce all the three standards under one roof. 

Types of Volumetric Flask:

Types: Four types of volumetric flasks meet the ASTM E228 Standards.

    These are as follows : 

1. Individually Certified Flasks with a Glass Stopper. 
2. Batch Certified Flasks with a Glass Stopper. 
3. Batch Certified Flasks with a Snap Cap. 
4. Individually Certified Flasks with Amber Color Glass to protect light-sensitive solutions. 

Sizes of Volumetric Flasks:

The volumetric flasks come in different sizes likewise 2 ml, 5 ml, 10 ml, 20 ml, 25 ml, 40 ml, 50 ml, 100 ml, 150 ml, 250 ml, 500 ml, 1000 ml, 2000 ml and 5000 ml. Glassco manufactures all sizes of flasks. The small volumetric flasks are used to prepare costly and precious drugs, whereas large volumetric flasks are used in pharmaceutical labs for preparing production batches.