Quantitative analysis in chemistry is the branch of analytical chemistry that determines how much of a particular substance is present in a sample.
In simple terms, while qualitative analysis identifies what substances are in a sample, quantitative analysis measures how much of each substance is present.
Key Points
- Purpose:
To measure the concentration or amount of chemical components in a sample. - Units of Measurement:
The amount is usually expressed in:- Molarity (mol/L)
- Mass percent (%)
- Parts per million (ppm)
- Grams or moles of analyte
- Types of Quantitative Analysis:
- Gravimetric Analysis: Involves measuring the mass of a substance to find its quantity (for example, by precipitating and weighing a compound).
- Volumetric Analysis (Titration): Involves measuring the volume of a solution of known concentration that reacts completely with the analyte.
- Instrumental Methods: Use instruments to obtain precise results, such as spectrophotometry, chromatography, atomic absorption spectroscopy, and mass spectrometry.
- Examples:
- Determining the percentage of iron in an ore sample.
- Measuring the concentration of glucose in a blood sample.
In summary:
Quantitative analysis provides numerical information about the composition of a substance or mixture and is essential in research, industry, and quality control.