Detection of Free Thiol Content

Free thiol, also known as hydrosulfide or thiol group, is the -SH group at the end of the side chain of the cysteine residue. It has reducibility and can be oxidized by oxidizing reagents to form various thiol modifications. The chemical properties of free thiols are very active. They can bind to proteins to change their structure and function, and they can also react with oxygen molecules to produce oxides that damage cells and tissues. In the body, the content of protein thiols is very abundant. The different thiol content can affect the different structures and functions of proteins, thereby affecting the biological life activities and physiological functions, so it is necessary to detect its content.

 

The detection of the content of free thiols is mainly based on the reducibility of thiols and their specific reactions with other chemical reagents. The commonly used detection methods include the following:

 

Colorimetry

1. Principles

The thiol group reacts with a specific reagent to cause a redox reaction, which causes a color change. The content of free thiols is calculated by measuring the absorbance. The commonly used colorimetry method is the Ellman method, which is currently the most widely used method for detecting free thiol content.

 

2. Features

It is simple and fast, the cost is relatively low, and it is suitable for preliminary screening of a large number of samples; but the sensitivity is relatively low.

 

Chromatography

1. Principles

It is mainly based on the difference in the interaction between the thiol group and the fixed phase or the mobile phase in the chromatographic column, and the thiol content is determined by chromatographic separation and detection. These include high-performance liquid chromatography and capillary electrophoresis.

 

2. Features

It has strong separation capability and is suitable for analysis of complex samples; but the operation is relatively complicated and time-consuming.

 

Fluorescence Spectroscopy

1. Principles

The free thiol is quantified by measuring the fluorescence intensity based on the interaction between the thiol group and a specific fluorescent probe.

 

2. Features

High sensitivity, good selectivity, and suitable for the detection of trace samples; but it requires specialized fluorescence detection equipment, and the cost is relatively high.

 

Electrochemical Method

1. Principles

Using the reducibility property of thiol group, electron transfer reaction occurs on the electrode surface, and free thiol is detected by measuring current or potential.

 

2. Features

High sensitivity and fast response speed; but the equipment cost is high, and it may be interfered by other electroactive substances.

 

Mass Spectrometry

1. Principles

The content of free thiols is determined by separating and detecting compounds containing thiol groups through mass spectrometry technology.

 

2. Features

High accuracy and resolution, and it can directly measure the types and quantities of free thiols in the sample; but the sample pretreatment is complicated and the cost is high.

 

The above methods have their specific application ranges and limitations, so in practical applications, various factors need to be considered comprehensively, and the appropriate method should be selected according to the specific situation to measure free thiols. MtoZ Biolabs has developed various platforms for detecting the content of free thiols, which can meet your various requirements. Please feel free to consult us.