Amino Acid Analyzer
Amino Acid Analyzer
Introduction
Amino acid analyzer, a cation exchange chromatographic separation, ninhydrin post-column derivatization method, analyzes the components of protein hydrolysates and various free amino acids, but details the instrument for amino acid analysis.
Using classical cation exchange chromatography and ninhydrin post-column derivatization, the content of protein hydrolyzate and various free amino acids were analyzed. The basic structure of the instrument is similar to that of normal HPLC but details are optimized for amino acid analysis (eg nitrogen protection, inert tubing, online degassing, elution gradient and column temperature gradient control, etc.).
system
Often subdivided into two systems: the proteolytic analysis system (sodium salt system) and the free amino acid analysis system (lithium salt system), gradient elution is performed using sodium citrate or lithium citrate at different concentrations and pH values. The sodium salt system analyzes up to about 25 amino acids at a time at a faster rate and has a good baseline flatness. The lithium salt system analyzes up to about 50 amino acids at a time, at a slower rate, and the baseline is generally not as good as the sodium salt system.
effect
Analysis Results: Compared with the methods of pre-HPLC derivatization (HPLC: <0.5 pmol; amino acid analyzer: <10 pmol), the sensitivity (lowest detection limit) , Reproducibility, ease of operation, operating costs, etc., are superior to other analytical methods.
Amino Acid Analyzer Selection
1, the principle. Ion exchange chromatography (IEC) based on cation exchange column separation, post ninhydrin derivatization, spectrophotometry. Such methods, invented by both Stein and Moore in 1958, were awarded the Nobel Prize in 1972 and are today's international and national standards as well as methods of arbitration and foreign involvement.
2, an important indicator. Analytical needs to meet the technical indicators such as resolution, repeatability and other requirements, and the degree of separation is a more important indicator, because the chromatographic theory generally with the resolution of 1.2 as the basic premise of the separation of two peaks, only the peak separation It makes sense to discuss qualitative and quantitative repeatability.
3, the authenticity of the indicator. Some manufacturers only indicate the individual amino acid indicators such as Asp or Arg, or only the average data to replace all the data, etc., and the instrument performance is good, business reputation of the manufacturers will mark all the amino acid indicators for the user reference.
4, the reliability of the instrument. If the instrument is blocked today and will leak tomorrow, users will not only have to pay a lot of manpower and money, but also reduce the credibility of the analysis results.
5, the operating costs of the instrument. For example, whether domestic reagents can be used, column lifetime (how many injections are calculated, not how many years to calculate, etc.).
6, whether the instrument design is conducive to amino acid analysis. Such as the presence or absence of inert gas protection (ninhydrin extremely susceptible to oxidation), whether to provide online degassing, whether to provide refrigeration control of the solution and sample, and the like.
7, after-sales service. Difficulties encountered in the analysis process are inevitable, manufacturers must be able to respond quickly to solve the problem as soon as possible. In addition, the price of commonly used spare parts is also an important factor, because users generally difficult to notice the sale of the problem before the purchase, but many manufacturers did not publicize their common spare parts prices, which laid the hidden dangers for future use, in fact, There are indeed a lot of instruments in the emergence of some seemingly minor failure, because the maintenance costs are too high and was "shelved."
Introduction
Amino acid analyzer, a cation exchange chromatographic separation, ninhydrin post-column derivatization method, analyzes the components of protein hydrolysates and various free amino acids, but details the instrument for amino acid analysis.
Using classical cation exchange chromatography and ninhydrin post-column derivatization, the content of protein hydrolyzate and various free amino acids were analyzed. The basic structure of the instrument is similar to that of normal HPLC but details are optimized for amino acid analysis (eg nitrogen protection, inert tubing, online degassing, elution gradient and column temperature gradient control, etc.).
system
Often subdivided into two systems: the proteolytic analysis system (sodium salt system) and the free amino acid analysis system (lithium salt system), gradient elution is performed using sodium citrate or lithium citrate at different concentrations and pH values. The sodium salt system analyzes up to about 25 amino acids at a time at a faster rate and has a good baseline flatness. The lithium salt system analyzes up to about 50 amino acids at a time, at a slower rate, and the baseline is generally not as good as the sodium salt system.
effect
Analysis Results: Compared with the methods of pre-HPLC derivatization (HPLC: <0.5 pmol; amino acid analyzer: <10 pmol), the sensitivity (lowest detection limit) , Reproducibility, ease of operation, operating costs, etc., are superior to other analytical methods.
Amino Acid Analyzer Selection
1, the principle. Ion exchange chromatography (IEC) based on cation exchange column separation, post ninhydrin derivatization, spectrophotometry. Such methods, invented by both Stein and Moore in 1958, were awarded the Nobel Prize in 1972 and are today's international and national standards as well as methods of arbitration and foreign involvement.
2, an important indicator. Analytical needs to meet the technical indicators such as resolution, repeatability and other requirements, and the degree of separation is a more important indicator, because the chromatographic theory generally with the resolution of 1.2 as the basic premise of the separation of two peaks, only the peak separation It makes sense to discuss qualitative and quantitative repeatability.
3, the authenticity of the indicator. Some manufacturers only indicate the individual amino acid indicators such as Asp or Arg, or only the average data to replace all the data, etc., and the instrument performance is good, business reputation of the manufacturers will mark all the amino acid indicators for the user reference.
4, the reliability of the instrument. If the instrument is blocked today and will leak tomorrow, users will not only have to pay a lot of manpower and money, but also reduce the credibility of the analysis results.
5, the operating costs of the instrument. For example, whether domestic reagents can be used, column lifetime (how many injections are calculated, not how many years to calculate, etc.).
6, whether the instrument design is conducive to amino acid analysis. Such as the presence or absence of inert gas protection (ninhydrin extremely susceptible to oxidation), whether to provide online degassing, whether to provide refrigeration control of the solution and sample, and the like.
7, after-sales service. Difficulties encountered in the analysis process are inevitable, manufacturers must be able to respond quickly to solve the problem as soon as possible. In addition, the price of commonly used spare parts is also an important factor, because users generally difficult to notice the sale of the problem before the purchase, but many manufacturers did not publicize their common spare parts prices, which laid the hidden dangers for future use, in fact, There are indeed a lot of instruments in the emergence of some seemingly minor failure, because the maintenance costs are too high and was "shelved."
