Seminary of the Southwest Chemistry Presentation


chemistry: create 4 slides , on the first two part in document below, introduction and Comparison of Prior Methods/Procedures

Gonzalez Arturo
Molina Smith Paul
Nicklo Madeline
Zidan Haya
Introduction Theobromine/ caffeine/ catechin general structure and antioxidant
Chocolate is one of the most consumed products in the world. Therefore, understanding
its chemical compounds is important for the development of new chocolate-based products and
the widening of the varieties. Catechins are found in chocolate, tea and other consumed
products and they help in the regulation of blood pressure, shield the brain from diseases and
reduce weight. Therefore, understanding its chemical compounds is important for the
development of useful products like drugs that can help in treating certain diseases and
conditions. Catechins are predominantly found in tea which is often associated with the
feel-good effect it has on people especially by stimulating the brain and increasing alertness. It
is necessary to know more about them. Analyzing the anti-oxidant compounds of catechins will
provide more understanding of how they can be manipulated to have more benefits than the
existing ones to human beings. C15H14O6 is the structure of catechin which has two rings of
benzene as well as dihydropyran heterocycle containing a hydroxyl set on three carbons
(Grzesik et al., 2018). Antioxidants are able to help reduce damage to cells by reacting with free
radicals. Free radicals are often the waste product of cells and can cause damage to
surrounding cells through oxidative stress. Antioxidants react with these free radicals, therefore
eliminating the harmful effects.
Caffeine structure:
Catechins structure:
Gonzalez Arturo
Molina Smith Paul
Nicklo Madeline
Zidan Haya
Theobromine structure:
Antioxidant mechanism:
Antioxidant structure:
Gonzalez Arturo
Molina Smith Paul
Nicklo Madeline
Zidan Haya
Comparison of Prior Methods/Procedures
Natsume et al. (2000) is an analysis of polyphenols in chocolate. It examines
polyphenols in cacao, chocolate, and cocoa. It shows, through the normal phase liquid
chromatography analysis conducted that each polyphenol type can be understood based on its
size of molecules such as tetramers, tetramers, and timers. The analysis involved dark
chocolate as well as pure powder of cocoa. The analysis indicated that milk in chocolate affects
polyphenols analysis due to the binding between the protein of milk and polyphenols. Unlike
Natsume et al. (2000) analysis which uses the NP-LC method, the analysis of catechin
antioxidants will involve the use of the mass spectrometry method. The findings of Natsume et
al. (2000) show that milk protein binds with polyphenols. This study will improve on this finding
by avoiding the same challenges experienced by Natsume et al. (2000) in their analysis of
polyphenol compounds in cocoa and chocolate. Similar to the objective of Natsume et al.
P(2000) analysis, the catechin analysis will try to find out more about the antioxidant
compounds in tea just as the literature analyzes polyphenols in chocolate.
Selection of Methods/Procedures (6 pts)
We have opted to use the method of High Performance Liquid Chromatography (HPLC). We
have selected this method because we have studied how this instrument works and feel like it is
the simplest, as well as available at CSUSM. We chose to follow the methods presented in
Reference 2 because we felt like their methods for determining the amount catechin were the
simplest. In their experiment, they tested both chocolate and cocoa powder, and we felt as
though that would be an interesting comparison, as we wondered if the catechin concentration
would decrease when the chocolate was in a powder form. We also chose to follow this method
because the specific steps were listed clearly, and this method used chemicals we were familiar
with and had worked with before, such as methanol and orthophosphoric acid. Reference 2 also
provided data for different brands of chocolate, which no other source provided. This could be
useful if we decide to compare brands as well. We also chose to follow this procedure because
it was more time efficient than any other method presented. The total time for the solution in the
chromatogram would be around 40 minutes, which is less than any other procedure.
(Source 2): reference
1) Preparation of chocolate sample and cocoa powder sample.
Step 1 Obtain .5000g of chocolate and .5000g of cocoa powder. Dissolve each of the solvents in
a volumetric flask to the 10mL mark using an organic solvent. Pass the samples through the
Chromatography machine. Obtain the following Instrument name, column type, carrier gas,
column dimension length, interior diameter, volume injected, injection port temperature, detector
temperature, flow rate, unretained void time. Analyze the results of the sample identify the
caffeine component
2) HPLC Conditions
Gonzalez Arturo
Molina Smith Paul
Nicklo Madeline
Zidan Haya
Column Used: reverse phase C-18 column (TARGA) (nonpolar and slowly add polar)
HPLC system: UV/vis detector (TARGA)
Detection Wavelength: 280 nm
Injection Loop Size: 10 uL
Flow rate: 1.0 mL/min
Mobile Phase: hexane
Method (application of the gradient)
Isocratic: 20 min
Volume of Standard Solution Made = 100 mL
Concentration of STOCK solution = 4 mg/mL
Concentration of Standard Solution
Volume of Stock Solution used (mL)
Catechin: 200 ug/mL (0.2 mg/mL)
2 mL
Catechin: 400 ug/mL (0.4 mg/mL)
4 mL
Catechin: 600 ug/mL (0.6 mg/mL)
6 mL
Epicatechin: 200 ug/mL (0.2 mg/mL)
2 mL
Epicatechin: 400 ug/mL (0.4 mg/mL)
4 mL
Epicatechin: 600 ug/mL (0.6 mg/mL)
6 mL
Preparation of Calibration Curve:
Gonzalez Arturo
Molina Smith Paul
Nicklo Madeline
Zidan Haya
Dilution of catechin and epicatechin at 100-600 ug/mL. Peak Height Catechin: 1475, Peak
Height Epicatechin: 1550, Peak Height Godiva Chocolatier (unknown): 2600.
Reverse Phase
HPLC column
https://www.hamiltonc $464
Agilent 1260 Infinity
HPLC System
Marshall $39,995
Gonzalez Arturo
Molina Smith Paul
Nicklo Madeline
Zidan Haya
V. References
1. Raju V.S.S. G, Nareshraju N., Kannababu S., Gottumukkala V. S.,Determination of
Catechin and Epicatechin Content in Chocolates by High-Performance Liquid
Chromatography. International Scholarly Research Notices, Volume 2014, 5 pages,
2. Grzesik, M., Naparło, K., Bartosz, G., & Sadowska-Bartosz, I. (2018). Antioxidant
properties of catechins: Comparison with other antioxidants. Food chemistry, 241,
3. Natsume, M., Osakabe, N., Yamagishi, M., Takizawa, T., Nakamura, T., Miyatake, H., …
Yoshida, T. (2000). Analyses of polyphenols in cacao liquor, cocoa, and
chocolate by normal-phase and reversed-phase HPLC. Bioscience, biotechnology a
biochemistry, 64(12), 2581-2587.

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