Chlorophyll is an important pigment in plants and some plankton, and plays a vital role in photosynthesis. Chlorophyll determination is a common analytical method to determine the chlorophyll content in samples. The principle of chlorophyll determination is based on the absorption characteristics of chlorophyll. In the visible region, chlorophyll has obvious absorption peak, and the absorption is strongest between blue-violet light and red light with wavelengths of 440 nm and 663 nm.
The steps of chlorophyll determination are as follows:
1. sample preparation: firstly, the sample to be tested needs to be extracted. The common extraction method is to add samples into organic solvents (such as ethyl acetate) to release chlorophyll from cells and form chlorophyll extract.
2. Optical density measurement: put the chlorophyll extract in an ultraviolet-visible spectrophotometer or spectrophotometer, and select the appropriate wavelength for measurement. Generally, two wavelengths, 440 nm and 663 nm, can be selected. Measure the absorbance of the sample solution at these two wavelengths respectively.
3. Calculation of chlorophyll concentration: According to the optical density measurement results, calculate chlorophyll concentration by colorimetry or standard curve method. In colorimetry, the concentration of chlorophyll in an unknown sample is determined by comparing it with a chlorophyll solution with a known concentration. The standard curve method is to measure the absorbance according to the standard solution with known concentration, then draw the standard curve, and get the chlorophyll concentration by reading the absorbance of the unknown sample, looking up the table or calculating.
In the process of chlorophyll determination, it may be interfered by other pigments and substances, so it needs to be corrected accordingly. Commonly used correction methods include acidification, alkalization, ethanol extraction and high temperature extraction. The determination of chlorophyll has important application value in ecology, agriculture, environmental science and other fields. It can be used to determine the chlorophyll content in plant leaves, so as to evaluate the photosynthetic capacity and growth state of plants.
In water quality monitoring, chlorophyll determination is also widely used to determine the biomass of algae in water to evaluate the degree of water pollution and eutrophication. Chlorophyll determination is a method to determine chlorophyll content in samples by light absorption method. Based on the absorption characteristics of chlorophyll, it calculates the concentration of chlorophyll by measuring the absorbance of the sample at a specific wavelength. Chlorophyll determination is widely used in scientific research and environmental monitoring, which is of great significance for understanding plant growth and water health.
Benefits of chlorophyll determination
1. Plant health assessment: Chlorophyll is the key pigment for plants to absorb light energy and carry out photosynthesis. By measuring chlorophyll content, the health status of plants can be evaluated. If the chlorophyll content is low, it may indicate that plants are under some kind of pressure, such as insufficient nutrition, pests and diseases or environmental stress, which is helpful to find and deal with plant growth problems as soon as possible.
2. Evaluation of photosynthetic efficiency: Chlorophyll is the key medium of photosynthesis, and photosynthetic efficiency can be evaluated by measuring chlorophyll content and related parameters. This is helpful to understand the utilization of light energy by plants, optimize the process of photosynthesis and improve the growth and yield of plants.
3. Genetic engineering screening: In genetic engineering and transgenic research, the determination of chlorophyll content can be used as one of the indicators for screening and evaluating gene transduction effect. By detecting the changes of chlorophyll, the expression of the target gene in transgenic plants can be determined and the transgenic effect can be preliminarily evaluated.