Chuxin Chen Analytical problem: comparative analysis of arbutin and tranexamic acid in skin whitening products.
The research project was stimulated by the increasing tendency in consuming skin whitening products in the Asian beauty market. The research is important because a large number of Asian women use different kinds of whitening products to their skin every day. Sorts of anti-pigmentation compounds were added into the products, these products varies from prices and the effectiveness of whitening.
What I am going to make a comparison is the arbutin and tranexamic acid. Arbutin is widely used in the products with fair prices and the tranexamic acid is always preferred by the luxury products. The comparison will mainly focus on the whitening effects of the products with these two compounds and try to find out that the luxury component is not much better than the normal one. The hypothesis is tranexamic acid has better performance in skin whitening and more reliable to use externally.
The featured arbutin-added whitening product in the Asian beauty market is α-arbutin serials from DHC, Japan, and the tranexamic acid is mainly used by the sheiseido brand's whitening line. Thus the matrix of the analyte is whitening cream containing arbutin and whitening cream with tranexamic acid.
UV VIS ABSORPTION SPECTROMETRY
For arbutin, the maximum wavelength of the absorption is 227nm, the analyte was dissolved in the deionized water, the HPLC eluent was 40% methanol(v/v) in 0.02M phosphate buffer. however, the molar absorptivity cannot be found in various of articles, it is also difficult to figure out since no complete calibration curve was given.
Tranexamic acid: according to the research, the tranexamic acid compound is unable to be directly analyzed by the UV-Vis since no chromophore is in the molecule.(1) However, the derivatization is a better choice, through a high yield and sensitive reaction to the original analyte, make it more sensitively to be seen by the UV-Vis system.
Three most important steps of the experiment are:
1. Find out a suitable derivatizing agent, conduct the reaction with the target analyte. (the reaction should be as complete as possible, the evaluation of the irreversibility and the sentivity of are important.)
2. Keep the derivatized product from light source, acids, bases and oxidizing agent in case of the conversion of the analyte's interest.
3. The need for internal standards should be evaluated improvement of the method. (4)
(1) Nycz, Jacek E.; Malecki, Grzegorz; Morag, Monika; Nowak, Gerard; Ponikiewski, Lukasz; Kusz, Joachim; Switlicka, Anna. "Arbutin: Isolation, X-ray structure and computational studies". Journal of molecular structures vol.980. 2010, (0022-2860)
(2)Shih, Ying; Wu, Kuan-Lin; Sue, Jun-Wei; Kumar, Annamalai Senthil; Zen, Jyh-Myng. "Determination of tranexamic acid in cosmetic products by high-performance liquid chromatography coupled with barrel plating nickel electrode" Journal of Pharmaceutical and Biomedical Analysis. (2008) 0731-7085
(3) "Microdialysis sampling coupled to on-line high-performance liquid chromatography for determination of arbutin in whitening cosmetics." Journal of chromatography. B. Vol.829. 2005(1570-0232)
(4) Beverly Nickerson. "Sample Preparation of Pharmaceutical Dosage Forms: Challenges and Strategies for Sample Preparation and Extraction". page 333. ISBN:9781441996305
SIMILAR ANALYTICAL PROBLEMS
My research project is similar to Melissa Eubanks' silicones in cosmetics, since we both focus on specific compound that added in the cosmetics and skincare products, the difference is , she concerns the silicione washedovers to the environment and my issue more concern about the human health. Another similar problem is Abdihakim Abdullahi's mercury in skin supplies, that we both want to analyze compounds in the skin whitening products, that we may have similar approach to determine the target ingredient in products.
Can be purchased at sigma-aldrich company, the product number is A4256. The sample has a purity higher than 98% and the price is $104.50 for 10g.
Can be purchased at sigma-aldrich company, the product number is 857653. The sample has a purity of 97% and the price is $41.50 for 10g
Atomic spectrometry is not useful to quantify the analytes , mass spectrometry may be used to determine the quantity of the analyte.
Analyte arbutin has a molecular weight of 272.25, the nominal molecular weight is 272.
Analyte tranexamic aicd has a molecular weight of 157.21, and the nominal molecular weight is 158.
Proper of ionization sources may be FD-TOF and ESI-trip Quad.
The mass spectrum(7) of tranexamic acid has its base peak at 122.7, and other peaks are at 95.1, 141.0 and 158.0. The spectrometry was LC-MS/MS, the spectrum was got by a sample which has a tranexamic acid concentration of 1E-4g/ml. The chromatohrapy was performed on surveyor liquid chromatography system, using a 5 micro hypurity C18 thermohypersil column (150*2.1mm i.d.) maintained at 20 oC.
The mass spectrum of arbutin was determined by a GC-MS spectrum(8), which is used very common in labs. The spectrum has its base peak at 73, however, the peak with is nominal molecular weight was not very high. The sample was prepared by diluted with DCM and injected 1micro liter in to the GC-MS system. The high purity helium was used as a carrier gas at 1ml/min flow rate. The oven temperature program was: from 120oC to 280oC in two minutes at a steady rate.
(7) Grassin Delyle, Stanislas. Clinica Chimica acta. 2010 Vol. 411 0009-8981
(8)Chisvert. A. Tanlata. 2010, Vol. 81. 0039-9140
Sample preparation of arbutin for GC/MS spectrometer. (9)
1. Sample was weighed out in proper amount, (0.01-0.02g), was weighed in a 10-ml volumetric flask.
2. Sample was dissolved in approximately 5ml of DMF (an ultrasonic water bath was used to facilitate the sample solving process).
3. The solution was then diluted to mark with the DMF to dilute the sample.
4. The solution was filtered with a 0.45µm nylon membrane filter.
Sample preparation of tranexamic acid for LC/MS-MS.(10)
1. 10ml of the internal standard solution (0.5g/L) was made and added into the 100µL sample which was contained into a 1.5mL plastic tube.
2. 100µL of perchloric acid(2.5% w/w) were than added.
3. sample was then vortex mixed for 30s and centrifuged at 14,000rpm for 10min.
4. 100µL of the aqueous supernatant was decanted into another tube and 150µL of sodium hydroxide (0.1M) was added.
5. sample was vortex mixed for 10s, and transferred into injection vials for analysis.
(9). Microdialysis sampling coupled to on-line high-performance liquid chromatography for determination of arbutin in whitening cosmetics. Journal of chromatography.B. 2005, vol.829, 1570-0232.
(10).Gaussin Delyle. S. , Chinica Chimica Acta., 2010. Vol. 411., 438-443
1. For my analytical problems, the gas chromatography, reverse phase chromatography, HILIC, affinity chromatography, chiral chromatography and size exclusion chromatography are suitable for analyze the compounds.
The Ion-Exchange chromatography is not suitable since there are no ions in my interested analytes.
2. I think the reverse phase chromatography is the most suitable technique to determine both analytes. Since both compounds are polar in structures, however, they each varied in the polarity substantially, the reversed phase chromatography is a good technique to separate.
3. The Nucleosil brand C18(11) (10µm,25*0.46cm) column was used for the separation, it is the medium density octadecyl , endcapped column, the structure of the stationary phase is "-(CH2)17-CH3". The PH stability of 20oC: 2-8, the number is 718966.
4. The mobile phase for the separation was acetonitrile/water (v:v 50:50), the PH of the mobile phase was adjusted to 2.6 by phosphoric acid (85%, w/w).(12)
5. The detector I am going to use is the UV-Vis detector, since both analytes are absorbed and emitted in the UV range.
(12): M. Saeed Arayne, Naima Sultana, Faiza Qureshi, Farhan Ahmed Siddiqui, Agha Zeeshan Mirza, Saima Sher Bahadur,Muhammad Hashim Zuberi., Chromatographia, 2009, Vol.70, 789-795
Both of arbutin and tranexamic acid are electroactive, thus the capillary electrophoresis method was able to determine and quantify the analytes in samples.
Instrumentation: it is performed using a CHI 821b electrochemical workstation. The reference electrode is Ag/AgCl , the platinum wire is as the auxiliary electrode. The detector is the UV-Vis detector.
Sample prepration: sample and MnO2 powder (particle size≤5 µm) are prepared and make into an aqueous solution with deionized water. The standard stock solution (10 000 ppm in 0.1M H3PO4) is going to be diluted by H3PO4 in different volumes to make different standard sample solutions.
To quantify the analytes in samples, it is useful to detect the current of each samples since the concentration of analytes is proportional to the currents.
(14)Jyh-Myng Zen, Hsueh-Hui Yang, Mei-Hsin Chiu, Chao-Hsun Yang, Ying Shin. Journal of AOAC International. Vol. 94, 2011, 985-990