The low-pressure liquid chromatography separation chromatography system is suitable for scientific research and preparation in industries such as biochemistry, synthetic chemistry, natural products, drug development, food chemistry, agricultural chemistry, cosmetics, polymers, and petrochemicals. Ion exchange chromatography, affinity chromatography gel filtration chromatography, hydrophobic interaction chromatography and other methods can be used for the separation, analysis and flow detection of proteins, enzymes, nucleic acids, nucleotides, polypeptides, (with or without aromatic amino acids) and any other biological/non biological samples with UV absorption. It is an ideal choice for biological molecule purification. It has many functions, simple use, economy and other characteristics. Compact design maximizes space savings in cold storage and laboratories.

notes

The technical specifications of the high-performance dual beam ultraviolet detector in the system configuration are required for quantitative testing of drugs in pharmaceutical factories across the country. Characteristics of Instruments and Equipment

Protein 280nm/254nm dual wavelength measurement

Aromatic amino acids such as tyrosine and tryptophan containing conjugated double bonds in protein molecules. They have the property of absorbing ultraviolet light, with the absorption peak at 280nm wavelength, and the optical density value of the absorption peak within this wavelength is proportional to its concentration. Therefore, it can be used as a basis for qualitative and quantitative determination of proteins. Therefore, the ultraviolet absorption method at 280nm is usually used for continuous monitoring of protein concentration in chromatography systems. However, due to the different contents of tyrosine and tryptophan in various proteins, accurate quantification requires the use of pure samples of the protein to be tested as standards for comparison, or the extinction coefficient of the protein already known as a reference. In addition, many non protein substances also have a certain absorption capacity at a wavelength of 280nm, which may cause interference. Among them, the impact of nucleic acids (purine and pyrimidine bases) is particularly severe. The absorption at 280nm is 10 times stronger than that of protein (per gram), but

The absorption of nucleic acid is stronger at 254nm, with a peak around 254nm. The extinction coefficient at 254nm for nucleic acids is twice that at 280nm, while for proteins it is the opposite, with 280nm UV absorption being greater than the absorption value at 254nm.

usually

The light absorption ratio of pure protein: A280/A254>1.8

Light absorption ratio of pure nucleic acid: A280/A254<0.5

Therefore, when nucleic acids are present simultaneously in protein solutions (as is the case in most biological systems), both OD254nm and OD280nm must be measured simultaneously. Then, based on the ratio of absorbance of two wavelengths, the true protein content is calculated by correcting it through empirical formulas to eliminate the influence of nucleic acids.

Protein concentration=1.45 × A280-0.74 × A254 (mg/ml)

This empirical formula is established based on data obtained from a mixture of proteins (yeast enolase) and nucleic acids (yeast nucleic acid) at known concentrations and ratios.

System configuration