I. Definition and Common Applications of Glass Capillary Tubes: Glass capillary tubes are a type of glass tubing, typically finer than ordinary glass tubes. With diameters ranging from a few micrometers to several hundred micrometers, they are referred to as capillaries. Glass capillary tubes find frequent use in laboratory settings for the suction and separation of minute liquid samples. In medical and life sciences, they are commonly employed for sampling and analyzing fluids such as blood and urine.

II. Usage Guidelines and Precautions for Glass Capillary Tubes:

1. Selecting Appropriate Glass Capillary Tubes: Different experiments and applications require various types and sizes of glass capillary tubes. When selecting a glass capillary tube, considerations should be made based on the experiment's requirements and the capillary tube's characteristics.

2. Preparing Samples and Glass Capillary Tubes: Prior to using glass capillary tubes, it is essential to prepare both the sample and the capillary tube. The sample should be placed in a container, and tools like droppers can be used to draw it to the bottom of the glass capillary tube.

3. Drawing Samples: Position the glass capillary tube in the sample, pinching the top with fingers. Subsequently, lift the capillary tube from the container and, upon releasing the fingers, allow the capillary tube to naturally draw in the sample. For extracting more liquid, the capillary tube can be returned to the container, repeating the procedure.

4. Recording Results: After completing the experiment, documenting the results and noting the conditions and techniques used is crucial.

It's important to exercise caution while handling glass capillary tubes due to their fragility, avoiding breakage or damage during use. Additionally, considering their small size, glass capillary tubes can be easily swallowed or accidentally introduced into the eyes, necessitating careful handling.

The above outlines the fundamental methods and precautions for using glass capillary tubes. Readers are encouraged to correctly utilize and maintain glass capillary tubes for improved experimental outcomes.