Lab Plastic Measuring Cylinders

Choose a measuring cylinder where the volume you need to measure falls between 20% and 80% of the cylinder's full scale. Reading near the bottom or top of the scale reduces accuracy. A 100 ml cylinder is ideal for 20 ml to 80 ml measurements. Using a 1 000 ml cylinder to measure 10 ml gives a very inaccurate reading.

Class B PP measuring cylinders are suitable for most teaching and routine laboratory work, with a tolerance of approximately plus or minus 1%. For analytical or primary standard work requiring tighter tolerances, use a calibrated borosilicate glass measuring cylinder or a calibrated volumetric pipette. Class B is adequate for all South African school curriculum requirements.

Polypropylene resists most dilute mineral acids, alkalis, and aqueous reagents at room temperature. Avoid concentrated nitric acid, chlorinated solvents, aromatic hydrocarbons, and ketones, which attack PP. For these chemicals, use borosilicate glass cylinders. Always consult a chemical compatibility guide for the specific reagent and concentration.

PP measuring cylinders can be autoclaved at 121 degrees Celsius and are the correct choice for microbiology or cell culture applications where the cylinder needs to be sterile. Remove any internal float or insert before autoclaving. Polycarbonate cylinders should not be autoclaved as they will warp and cloud.

A Class B polypropylene measuring cylinder is accurate to approximately plus or minus 1% of the stated volume, which is the same accuracy grade as a Class B glass measuring cylinder. For a 100 ml cylinder, this means a tolerance of plus or minus 1 ml. Class A glass cylinders have tolerances roughly half those of Class B and are used for more demanding analytical work. For school and routine lab use, Class B PP cylinders are more than adequate.

With most aqueous liquids in PP, the meniscus curves upward at the edges (convex) rather than downward as it does in glass. Read the volume at the bottom of the meniscus for aqueous solutions. Hold the cylinder at eye level on a flat surface and read the scale at the lowest point of the liquid surface. Avoid reading from above or below, as parallax error will give a false reading. Use a dropper or pipette to add the final drops if you are just short of the mark, or to draw off any excess if you have overshot, and never pour that removed liquid back into your original container, since this risks contaminating the rest of your stock. Keep the cylinder on the bench rather than lifting it while you pour, to reduce the risk of a spill.

PP measuring cylinders resist many mild organic solvents including alcohols (ethanol, methanol, isopropanol) and dilute acetic acid. However, PP is attacked by chlorinated solvents (chloroform, dichloromethane), aromatic hydrocarbons (toluene, xylene), and ketones (acetone, MEK). For these solvents, use a borosilicate glass measuring cylinder. Always check compatibility before use.

A displacement vessel (overflow can or Eureka can) is an open-topped container with a side spout at the water level, used in Archimedes principle and density experiments to collect the water displaced by a submerged object. Unlike a measuring cylinder, it is not calibrated for direct volume reading. The displaced water is collected in a measuring cylinder and measured separately to determine the volume of the submerged object.

Yes, polypropylene measuring cylinders can be autoclaved at 121 degrees Celsius using a standard steam autoclave cycle. This makes them suitable for microbiology, cell culture, and biological assay applications where sterile glassware is required. After autoclaving, allow the cylinder to cool fully before handling. Inspect after multiple autoclave cycles for cloudiness or brittleness, which indicate material fatigue.