Laboratories require equipment like beakers, conical flasks, pipettes, and measuring cylinders for measuring, mixing, and making various specimens and chemicals.
A graduated cylinder, or measuring cylinder, is used mainly in laboratories requiring moderately precise volume measurements. It is narrow and cylindrical with markings for volume measurement. Along with the volume of liquid, it is also indirectly used to measure the mass of a solid.
Based on volume, the graduated cylinder is of different types; 5 ml, 10 ml, 25 ml, 50 ml, 100 ml, 250 ml, etc. Another basis for division of its type is material used to make it; either plastic or glass.
Types of Graduated Cylinder
The laboratory equipment is divided into different types based on style, materials used, precision, and size/volume capacity. Usually, two kinds of material are used to construct measuring cylinders; glass or plastic. The variety in size range is high in measuring cylinders, from 5 ml to 4000 ml.
- Based on the materials used: Usually laboratory equipment that comes in contact with chemicals and specimens are made up of either glass or plastic so, the graduated cylinder is also of two types based on the material used for its construction.
- Plastic measuring cylinder: Two types of plastic material are used in the construction of measuring cylinders; TPX® polymethyl pentene (PMP) and polypropylene. The graduated cylinder made up of clear TPX® polymethyl pentene (PMP) is expensive but easy to handle and read. The material can tolerate high heat at 177℃ and are autoclavable at 121℃. However, they are brittle in comparison to polypropylene. Polypropylene is a translucent plastic with total contained (TC) and total delivered (TD), two measurement scales for precision. These are also autoclavable; however, their thermal tolerance is lower than that of TPX® polymethyl pentene (PMP). (2) A plastic graduated cylinder is usually preferred when the volume measurement is above 1000 ml.
- Glass measuring cylinder: The glass used to make graduated is borosilicate. The borosilicate is known for its low thermal expansion and maintaining transparency and strength even under high temperatures, is 268 ℃. Glass measuring cylinders are fragile, so smaller sizes, i.e., up to 1000 ml are only available.
- Based on Precision: Based in the precision glassware are of 2 types; class A and class B. Class A is twice more precise than type B. (3)
- Class A: It is glass measuring cylinders made with borosilicate. It is more accurate than the class B types. It has more thermal and chemical resistance. These are ISO9000 compatible and usually preferred for volumetric analysis.
- Class B: It is made up of soda-line glass or borosilicate (depending on the manufacturer) and used for general laboratory purposes. The basic design is the same as class A but with fewer volumetric tolerances than class A. It is not preferred for prolonged exposure to chemicals.
- Based on the measurement capacity: The graduated cylinder is divided into several different types based on its capacity to measure the volume. Their dimensions and tolerance of each kind are as follows: (1)
- 5 ml: The least graduation is 0.1, and the main graduation marking is every 1.0, with graduation intermediate at 0.5. The minimum wall thickness is 0.9 mm, and the maximum inner diameter is 11.2 mm. In the case of style II, the standard taper stopper number 9 is applicable. Tolerance to contain and to deliver for class A is 0.05 ml, and for class B is 0.10 ml.
- 10 ml: The 10 ml graduation cylinder is constructed with class A or class B precision tolerance to contain or deliver, which are 0.10 ml and 0.20 ml, respectively. The least graduation marking of a 10 ml graduated cylinder can be either 0.1 or 0.2, the main marking is 10.0, and the intermediate graduation is 0.5 (in the case of 0.1 least marking only). The minimum wall thickness is 1.9 mm, and the maximum inner diameter is 15.2 mm.
- 25 ml: Like the 10 ml cylinder, 20 ml is also constructed in either class A or B precision with tolerance to contain and deliver 0.17 ml and 0.34 ml. The minimum wall thickness for a 20 ml cylinder should be 1.1 mm. Based on this, the main graduation marking can change from 2.0 to 5.0; the maximum inner diameter also varies from 18.5 mm to 19.3. The least marking also changes from 0.2 in 2.0 to 0.5 in 5.0 main. However, the intermediate graduation marking is the same, 1.0.
- 50 ml: The main marking is either 5.0 or 10.0, and the least is 1.0. In the case of the main marking at 10.0 intervals, the intermediate is at 5.0. The maximum inner diameter is 23 mm, and 1.2 mm is the minimum wall thickness. The tolerance to contain or to deliver for class A and class B are 0.25 ml and 0.50 ml, respectively.
- 100 ml: The main marking is at the interval of 10.0, the intermediate marking at 5.0, and the least at 1.0. The tolerances to deliver or to contain for class A and class B are 0.50 ml and 1.00 ml. The maximum inner diameter for construction is 29.6 mm, and the minimum wall thickness is 1.3 mm.
- 250 ml: The main marking is at the interval of 20.0, intermediate at 10.0, and the least at 1.0. The tolerance to contain and to deliver for class A and class B are 1.00 ml and 2.00 ml. The maximum inner diameter is 42.4 mm, and the minimum wall thickness is 1.5 mm.
- 500 ml: The tolerance to contain or to deliver for class A and class B are 2.00 ml and 4.00 ml. The minimum wall thickness for construction is 1.6 mm, and the maximum inner diameter is 50.8 mm. The least marking is at the interval of 5.0, the intermediate at 25.0, and the main marking at 50.0.
- 1000 ml: The main marking is at the interval of 100.0, the intermediate marking at 50.0, and the least at 50.0. The maximum inner diameter for construction is 63 mm, and the minimum wall thickness is 2.0 mm. The tolerance to contain or to deliver for class A and class B are 3.00 ml and 6.00 ml.
- 2000 ml: The maximum inner diameter for construction is 82.1 mm, and the minimum wall thickness is 2.0 mm. The tolerance to contain or to deliver for class A and class B are 6.00 ml and 12.00 ml. The main marking is at the interval of 200.0, the intermediate is at 100.0, and the least graduation marking is at 20.0.
- 4000 ml: The tolerance to contain or to deliver for class A and class B are 14.50 ml and 29.00 ml, respectively. The maximum inner diameter for construction is 110 mm, and the minimum wall thickness is 2.2 mm. The main graduation marking is 500.0, the intermediate marking is 250.0, and the least marking is 50.0.
- Based on the style: The style or design greatly influence the purpose of graduated cylinder. Based on the style graduated cylinder is of three types: (1)
- Style I: The topmost (lip) is beaded with a spout for easy pouring.
- Style II: The topmost part of this style has a grounded standard tapered neck. A stopper is placed on it to prevent spillage.
- Style III: The style is similar to that of style I with the beaded lip and spout at the topmost part, except it has a reinforcing band near the top. The band is usually made of rubber or plastic.
Parts of Graduated Cylinder
Almost all graduated cylinders have three fundamental parts; base, cylinder tube, and mouth.
- Base: The base of the cylinder is for support and keeping the cylinder upright.
- Cylindrical tube: It consists of the graduation mark, which indicates the volume. The top part of the graduated cylinder must consist of the maximum capacity, class in the ISO number (precision), and material it is made of (in the case of a glass cylinder).
- Mouth: It is the open end of the cylinder. There is the presence of a spout for easy pouring in styles I and III, whereas a tapered neck style opening is also available.
- Stopper: The stopper is used for sealing the mouth of the style II cylinder.
How to Use a Graduated Cylinder
The use of the correct measurement capacity of the cylinder depends on the purpose, availability, and logic. The graduated cylinder and thin and tall and can carry the risk of tipping over, so care must be taken when handling it. Following are some of the steps for using a graduated cylinder correctly: (1)
- Before pouring the liquid, you should always rinse it with the fluid to be poured. While pouring a liquid into the cylinder, use the non-dominant hand to hold the cylinder to prevent tipping over the cylinder.
- To see the exact amount of fluid in the cylinder, hold it around the top (where the graduation mark is not present) and bring it to eye level. Observe the lower meniscus of the fluids, which should be at the same level as your eyes. Sometimes placing black paper behind the cylinder is helpful as the reflection of the meniscus due to the paper is easier to read.
- The marking is split between 1 ml each, so the calculation of the exact amount of the liquid is done by mentally assigning lines 1 to 9. If the liquid is less than the desired volume, use a micropipette or plastic pipette and add the liquid dropwise and slowly until the desired volume is obtained.
- Rinse the cylinder after use with deionized water.
- For drying the rinsed cylinder, you can use filter paper. Take a filter paper longer than the length of the cylinder. Then, fold the filter paper lengthwise until it reaches the circumference of the cylinder and slowly thrust it up and down along the inside of the cylinder. The filter absorbs the moisture and dries the cylinder.
Calibrating a graduated cylinder
A graduated cylinder is calibrated by measuring the volume of water and determining the water’s mass. We know that the water’swater’s density is 1 g/ml at room temperature, which means 1 ml of water should be 1 g.
Steps for calibrating
- Place the cylinder on the weighing balance. Tare the balance to make the reading zero.
- Pour distilled water into the cylinder, up to 25% of its total capacity (be careful to measure the exact volume). Record the volume.
- Empty the water into a clean beaker. Weigh the new mass by placing the beaker in the balance. Record the mass. Empty and dry the beaker.
- Repeat steps 1 to 3 with 50%, 75%, and 100% of the cylinder’scylinder’s capacity.
- The mass of the empty cylinder is subtracted from the readings, which is the mass of water. Plot the difference in graph paper or computer graphing system. Draw a straight line through the origin. Refer to the graph when necessary.
Uses of Graduated Cylinder
The use of a graduated cylinder is in measuring volumes of the liquid accurately. It is preferred over a beaker and conical flask. The laboratories extensively using graduated cylinders are chemistry, biological, microbiological, and forensic laboratories. However, volumetric flasks and pipettes are preferred over graduated cylinders for more precise measurements during volumetric analysis.
- Specification for laboratory glass graduated cylinders. Book of Standards Volume.
- Graduated cylinders [Internet]. Graduated Cylinders | SPI Supplies. [cited 2023Jan1]. Available from: https://www.2spi.com/category/labware-graduated-cylinders/labware/
- Lab glassware: Class A vs class B [Internet]. Cambridge Environmental Products, Inc. [cited 2023Jan1]. Available from: https://cambridgeenviro.com/blogs/news/class-a-vs-class-b-in-lab-glassware
- Patnaik P. Dean’s Analytical Chemistry Handbook. New York: McGraw-Hill; 2004.