Analytical Chemistry, Chemical Analysis Process

 
It is the chemical formula of cocaine.

Benzoylecgonine, known as benzoyleggonin, is a metabolite released into urine after cocaine ingestion. Despite the similarity in chemical formula between cocaine and benzoylecgonine, their distinction is crucial in analytical chemistry.

Referencing the provided papers:

• Link 1
• Link 2

These articles illustrate how the analysis of cocaine and its metabolites serves as a representative example in analytical chemistry. They delve into the methodologies employed to differentiate between cocaine and benzoylecgonine, despite their chemical similarities. This analytical challenge underscores the importance of precise detection methods in various contexts, including drug testing and environmental monitoring.

Po River

Analyzing wastewater flowing into the Po River for benzoylecgonine, released from the bodies of Italians using cocaine, is essential.

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

The sample was collected, and a substantial volume of water sample was employed for liquid chromatography separation using solid-phase extraction to concentrate benzoylecgonine, with results obtained via mass spectrometry.

In this process, the transformation of cocaine into benzoylecgonine is referred to as the Analyte. Utilizing the solid-phase extraction method for sample collection and pretreatment, separation via liquid chromatography, and measurement through mass spectrometry can be regarded as the chosen analytical approach.

Sampling involves selecting either a homogeneous or heterogeneous sample, akin to choosing between a pure Americano or coffee with bubble tea. This selection process is critical for obtaining representative samples for chemical analysis.

Following sampling, sample preparation is essential. Sample pretreatment aims to prepare the sample for analysis by transforming it into a suitable state. For instance, grinding coffee beans into fine particles ensures thorough dissolution.

During sample pretreatment, the sample is typically mixed with a solvent to form a suspension, which is then centrifuged to separate layers and remove any unwanted components. For organic samples, adding an organic solvent and centrifuging as a suspension can separate fats in the supernatant, leaving the desired caffeine as a solid residue.

After pretreatment, comparison with a known aqueous solution involves transferring the samples and adding water. However, it's crucial to filter out any remaining fine particles in the unknown solution to ensure accurate analysis.

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

For this purpose, the supernatant liquid must undergo multiple centrifugation cycles to filter the turbid solution. This purification (washing) of the unknown solution is crucial to prevent column blockage.

These pretreatment steps, including solid-phase extraction, enable rapid sample processing. In the case of caffeine, which binds to C18 silica, elution with a methanol solvent facilitates easy collection via solid-phase extraction.

Depending on polarity, the solution is injected into the chromatography column. For instance, if both caffeine and theobromine are present, caffeine's stronger adherence to C18 silica particles allows for differentiation in speed and concentration within hydrocarbons attached to SiO2.

By employing analysis concentration confirmation methods and calibration curves, substance identification and quantification can be achieved. Drawing corresponding graphs facilitates easy confirmation in unknown samples.

To ensure reliable measurements and interpret results, calculating repeatability and standard deviations is essential. This process enhances the quality assurance of subsequent analyses.

In summary, today's discussion covers the selection of analytical processes (techniques), sample collection, sample preparation (obstruction removal), analysis (quality assurance and repeatability), and reporting and interpretation to derive meaningful results.

You can find the translated text in Korean here: https://biostudy.tistory.com/2