Label
Definition and meaning of Label in chemistry.
A label in chemistry is a detectable marker, such as a radioactive isotope or fluorescent dye, attached to a molecule to track its location or fate in an experiment.
In more detail
Labels serve as tracers that allow scientists to follow specific atoms or molecules through chemical reactions or biological processes. Radioactive isotopes like C-14 and tritium have been used historically, while modern research increasingly employs fluorescent dyes and enzyme tags that offer safety advantages. The ideal label does not significantly alter the chemical behavior of the molecule being tracked.
Key facts
| Field | Analytical Chemistry |
|---|---|
| Common radioactive labels | C-14, H-3 (tritium), P-32 |
| Non-radioactive alternatives | Fluorescent dyes, enzyme tags, mass labels |
| Purpose | Track molecular fate and identify reaction intermediates |
Carbon-14-labeled glucose (C-14 glucose) enables biochemists to track glucose metabolism by detecting where the radioactive carbon atoms end up in cellular pathways and metabolic intermediates.
Frequently asked questions
Why use a labeled compound instead of directly analyzing products?
Labels allow tracking of specific atoms through complex pathways and detection of short-lived intermediates that would be invisible without a tracer.
Are radioactive labels still commonly used today?
Yes, especially in biochemistry and medical imaging, though fluorescent and mass-based labels are increasingly preferred due to safety and ease of detection in living cells.