Analytical Chemistry, Chemical Analysis Process

It is the chemical formula of cocaine.

benzoylecgonie

It is benzoyleggonin, which is released into the urine after ingesting cocaine.

If you check cocaine and benzoyleggonin, you can see that there is not much difference in the chemical formula.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1190203/

http://www.chu.ulg.ac.be/upload/docs/application/pdf/2009-08/cocaine_env._pollution_2009.pdf

As can be seen from the above paper, the above example is a representative analysis example in analytical chemistry.

Po River

Analyzing wastewater flowing into the Po-River from benzoylecgonin released from the body of Italians using cocaine

https://en.wikipedia.org/wiki/Elution, example

The sample was collected, and a large amount of water sample was used as a liquid chromatography separation method using solid-phase extraction to concentrate benzoyleggonin, and results were obtained through mass spectrometry.

Here, the cocaine going to benzoylgonine is called Analyte.

Using solid phase extraction method, sample collection and pretreatment

Separation by liquid chromatography and measurement by mass spectrometry can be considered as the choice of analytical method.

Sampling is a small sample of a representative sample as the first step in chemical analysis.

Think of it as a commercial coffee as an example.

The amount of caffeine in each manufacturer's various coffees will be different.

Also, the amount of caffeine will vary for each type of coffee made by the same manufacturer.

 

You have to choose one of these two and take a sample

Also, I need to know if the sample I want to analyze is homogeneous and heterogeneous as a sampling strategy.

Examples of this are pure Americano or coffee with bubble tea.

Once you have sampled and sampled, you need sample preparation.

Sample pretreatment is to transform a sample into a state suitable for analysis.

An example is to grind coffee beans into small pieces to melt them well.

The sample is put in a solvent, mixed and made into a suspension, and then centrifuged to separate the layers to remove the liquid and supernatant from the layer.

If you extract the caffeine I want from an organic sample, add an organic solvent and centrifuge it as a suspension, the fat will melt in the supernatant, and the caffeine I want will be spread underneath as a solid residue.

The samples are transferred and water is added to compare the unknown aqueous solution with the known aqueous solution.

However, it is necessary to filter out the fine particles remaining in the unknown solution.

https://en.wikipedia.org/wiki/Column_chromatography

For this reason, the supernatant liquid must be filtered several times by centrifuging the turbid solution, because the unknown solution must be purified (washed) to block the column.

However, all of these pretreatments can be used to rapidly process samples by solid phase extraction.

In the case of caffeine, since it is fixed to C18 silica, it is eluted with a methanol solvent, so it can be easily collected by solid phase extraction.

Depending on the polarity, the solution must be injected into the chromatography column,

If there is caffeine and theobromine, caffeine is more soluble in C18 silica and strongly adheres to the particles of the column, so it is easy to confirm the difference in speed and concentration in hydrocarbons attached to SiO2.

Since it is possible to check the substances according to the concentration through the analysis concentration confirmation method and the calibration curve, if you draw the corresponding graph, it can be easily confirmed in the unknown sample.

So if you want to calculate repeatable measurements and standard deviations to interpret the results and add another analysis,

It can guarantee the quality of other samples

As a summary of what I wrote today

Selection of analysis process (analysis technique), sample collection, sample preparation (removal of obstruction), analysis (quality assurance and repetition), reporting and interpretation in order to derive results

You can see the text translated in Korean here.

https://biostudy.tistory.com/2