What is the role of the standard curve? The meaning and application of the standard curve

By measuring a certain physicochemical property of a series of reference materials of known composition, a curve composed of numerical values of this property is obtained. Standard curves.

It is a function of the physicochemical properties of the reference material and the response of the instrument.

In analytical chemistry experiments, the standard curve method is commonly used for quantitative analysis, and the standard working curve is usually a straight line.

Unlike calibration curves, it is a standard series of standard solutions and media plotted curves. The associated components of the standard series of the calibration curve must be matched to the specimen in order for the measurement results to be accurate. Only when the standard curve coincides with the calibration curve, the standard curve can be used instead of the calibration curve.

This is an important prerequisite for making a standard curve, and the question is actually very simple: can the instrument response of my sample be used to derive its physicochemical properties from the standard curve we have established? The answer is based on the specificity of the instrument's response and the matching of the standard series to the sample.

On the one hand, we always strive for the response of the instrument, and treat the standard and the sample equally; We also require that my samples match the standard matrix. So the best criterion is the matrix matching criterion, and the best criterion curve is the working curve. In this way, we can also understand why most analyses require the standard curve to be measured in the same batch as the sample (unless the standard curve does not change much after experimentation), and it is also easy to understand why we insert QC test samples to investigate the stability of the instrument when doing large batch tests.

Even if any information is unknown, we still have to do our analysis and test (or we are all unemployed), because we all do it in the same way, and we all make mistakes; It is also because we believe that as science advances, the closer the accuracy of the results we test will be.

1.The concentration in the sample is unknown, so we want to extrapolate the concentration corresponding to a range of response values with a limited standard response.

2.The standard curve reduces the possible error of a single standard.

Significance: Standard curve.

A mathematical term that refers to a curve composed of a numerical value of a defined property by measuring a series of known components of a reference substance. The standard curve is a function of the file group between the physicochemical properties of the reference material and the response of the instrument.

Application: Practicality, which is an important prerequisite for making a standard curve; The question is actually quite simple: can the instrumental response of a sample be used to derive its physicochemical properties from a standard curve?

The answer is based on the specificity of the instrument's response.

and the compatibility of standard series and samples above. On the one hand, scientific research always strives for the response of the instrument, and the standard and the sample are the same; At the same time, it is also required that the sample is matched to the standard matrix. In this way, it can be understood that most analyses require the standard curve and the sample to be measured in the same batch (unless the standard curve does not change much after experimentation), and it can also be understood that QC test samples should be inserted when doing large-scale testing to investigate the stability of the instrument.

<>1. Advantages of the standard curve method: after the standard working curve is prepared, the determination becomes quite simple, and the content can be read directly from the standard working curve, so it is especially suitable for the analysis of a large number of samples.

2. The disadvantage of the standard curve method is that it is difficult for the chromatographic conditions of each sample analysis to be exactly the same, so it is prone to large errors. In addition, when drawing the standard working curve, the standard sample of the component to be measured is generally used, but the composition of the actual sample is very different, so the matching will inevitably bring a certain error to the measurement.

<>1. Advantages of the standard curve method: after the standard working curve is drawn, the determination of rock and land rot becomes quite simple, and the content can be read directly from the standard working curve, so it is especially suitable for the analysis of a large number of samples.

2. The disadvantage of the standard curve method is that it is difficult for the chromatographic conditions of each sample analysis to be exactly the same, so it is prone to large errors. In addition, when drawing the rough leakage line of the standard working curve, the standard sample of the component to be measured is generally used, but the composition of the actual sample is very different, so it will inevitably bring a certain error to the measurement.

The principle of the standard curve method: the standard sample is formulated into a standard series of different concentrations, under the same chromatographic conditions as the components to be measured, the same volume is accurately injected, the peak area or peak height of each peak is measured, and the standard curve is drawn against the sample concentration with the peak area or peak height, and this standard curve should be a straight line through the origin. If the standard curve does not pass through the origin, there is a systematic error.

The slope of the standard curve is the absolute correction factor.

The standard curve method, also known as the external standard method or direct comparison method, is a simple and rapid quantitative method. Similar to the standard curve method in spectrophotometry, a standard curve is first drawn with a standard sample of the component to be measured. When determining the content of components in a sample, a chromatogram is made with the exact same chromatographic conditions as the standard curve drawn, the chromatographic peak area or peak height is measured, and then the concentration of the sample components injected into the column is directly detected on the wax standard curve according to the peak area and peak height.

Advantages of the standard curve method: After the standard working curve is drawn, the determination is quite simple, and the content can be read directly from the standard working curve, so it is especially suitable for the analysis of a large number of samples.

Disadvantages of the standard curve method: the chromatographic conditions (detector response performance, column temperature, mobile phase flow rate and composition, injection volume, column efficiency, etc.) are difficult to be exactly the same for each sample analysis, so it is prone to large errors. In addition, when drawing the standard working curve, the standard sample of the component to be measured (or the sample with the known accurate content) is generally used, but the composition of the actual sample is very different, so it will inevitably bring a certain error to the measurement of the wheel.

The standard equation for the curve is: (x-a) 2+(y-b) 2=r 2. Curves are one of the main objects of differential geometry research. Intuitively, the curve can be seen as the trajectory of the movement of the spatial point. Differential geometry is the use of calculus.

to study the discipline of geometry. In order to be able to apply the knowledge of calculus, we cannot consider all curves, not even continuous curves, because continuity is not necessarily differentiable.

An equation is an equation that contains unknowns. It is an equation that expresses the relationship between two mathematical formulas (such as two numbers, functions, quantities, and operations), and the value of the unknown number that makes the equation true is called the "solution" or "root". The process of finding the solution of an equation is called "solving an equation."

By solving the equation, you can avoid the difficulty of reverse thinking, and directly list the equation containing the quantity you want to solve. Equations have a variety of digging forms, such as unary equations.

Binary linear equations, unary quadratic equations.

and so on, you can also form a system of equations to solve multiple unknowns.