Class A Volumetric Flask

What is the Class A Volumetric Flask?

A Class A volumetric flask holds a single calibrated volume with a tight tolerance for standards and dilutions. Its long neck and single mark allow precise adjustment to the line, with a certificate for traceability.

Overview

The flask is made from borosilicate 3.3 with a narrow neck, a single graduation mark and usually a ground stopper or a plastic snap cap. It is calibrated to contain a stated volume at 20 °C, with tolerances from about ± 0.02 mL at 5 mL to ± 0.5 mL at 2000 mL depending on size, following ISO 1042. Broad sizes run from 5 mL to 2000 mL, and the neck diameter is small so the meniscus can be read accurately against the mark. Amber versions protect light-sensitive solutions, and some flasks have a wide neck for solids. Each flask should carry a certificate or individual serial number for traceability, and it is used to prepare standards, dilutions and mobile phases where the final volume must be known exactly.

How does it work?

Laboratory glassware works because borosilicate 3.3 is chemically inert, transparent and resistant to heat and thermal shock. Its low coefficient of expansion, about 3.3 × 10⁻⁶ per kelvin, means it tolerates rapid temperature change without cracking, and it resists attack by most acids, solvents and reagents, so it does not contaminate samples or react with them. Volumetric glassware carries a calibration mark and is made to defined tolerances: Class A flasks and pipettes hold or deliver a stated volume at 20 °C within a tight limit, while Class B allows a wider tolerance for less critical work. Graduations on cylinders and beakers are approximate. Ground joints and stoppers seal by friction, and standard tapers allow interchange. Because glass is brittle, care is needed with impact and with hydrofluoric acid and hot alkalis, which attack it.

What are the key features?

• Borosilicate 3.3 with single calibration mark
• Calibrated to contain at 20 °C
• Tolerance from ± 0.02 mL to ± 0.5 mL
• Sizes 5–2000 mL
• Ground stopper or snap cap
• Amber option for light-sensitive solutions

What are the technical specifications?

A typical class a volumetric flask configuration offers class of Class A, material of Borosilicate 3.3, volume range of 5–2000 mL, tolerance of ± 0.02 to ± 0.5 mL, calibration temperature of 20 °C and closure of Ground stopper or snap cap. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Class A Volumetric Flask is used in standard preparation, sample dilution, mobile phase preparation and volumetric analysis. Across the wider Glassware class, laboratories also deploy it for standard and reagent preparation, titration and volumetric analysis and sample mixing and heating.

Which standards and certifications apply?

Relevant standards and methods include ISO 3585 (borosilicate glass 3.3), ISO 1042 (one-mark volumetric flasks), ISO 385 (burettes), ISO 4788 (graduated measuring cylinders), ASTM E438 (glass composition) and USP <660> (glass containers). Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Clean glassware thoroughly, using a detergent suited to the residue and rinsing with reagent water, since residual detergent or acid affects results. Avoid abrasives and strong alkalis that etch glass and remove graduation marks, and never use hydrofluoric acid in glass. Dry volumetric glassware by air or with solvent rather than heat, because heating changes the calibrated volume. Handle ground joints carefully, store stoppers loosely or with a spacer and avoid seizing by keeping joints clean. Check for chips, cracks and star cracks before use, since damaged glassware can fail under vacuum or heat. Keep the calibration certificate and recheck or replace volumetric items that are damaged or of unknown history.

How do I select the right Class A Volumetric Flask?

Choose Class A flasks for any volume that must be exact, and size the flask to the final volume rather than diluting in steps. Confirm tolerance and certificate. RFQ: volumes, closure type, amber option and certificate needs.

How does it compare with other Glassware variants?

Choose the item by function and accuracy. Use Class A volumetric flasks and pipettes where the volume must be accurate, for standards, dilutions and titrations, and Class B or graduated items for approximate work. Select the material for the chemistry: borosilicate 3.3 for general laboratory use, and avoid glass for hydrofluoric acid, hot concentrated alkali and some fluoride-containing reagents, where plastic is safer. Match capacity and neck size to the application, and use narrow-neck flasks for mixing and wide-neck for solids. Check that graduations are legible and durable when buying, and confirm the calibration certificate for volumetric items. Consider whether low-extractable or amber glass is needed for light-sensitive or trace work, and plan cleaning and drying that will not damage the marks.