Research

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Abstract

This work was mainly to analyze the properties of the food dye Indigo Carmine (IC) for future examination in commercially consumed products. Different concentrations of IC were mixed with water by dilution and all concentrations were measured on the UV-Vis and the HLPC from a stock solution with concentration 3.2e-04 M to 1.005e-05, making five dilutions from the stock. The UV-Vis wavelength was used to determine the molar absorptivity of IC. This will help in its identification when testing for commercial products and with the instruments UV-Vis and HPLC concentrations could always easily be determined. The data also showed how the HPLC was more effective in measuring higher concentrations than the UV-Vis which could only produce smooth graph data under 1.6 absorbance.

Introduction

Some food dyes might be hazardous in certain quantities to people, therefore it is imperative that these food dyes made by companies are always researched upon and analyzed to make sure that they are being consumed at the right concentrations inside foods that they are mixed with. Using the UV-Vis and the HPLC, analysis of food dyes and discovery of their components at particular concentrations become possible. Indigo Carmine (IC), commonly known as food blue 1 or FD and C blue 2 is a synthetic blue dye that is usually found in cotton candy, icings, blue curacao liqueur sweets, soft drinks and many more. This dye IC has been said to be dangerous in consumable products at certain concentrations and has been known to induce allergic reactions in individuals with pre-existing moderate asthma. Being able to analyze the dye through the HPLC and the UV-Vis we would be able to quantify its abundance in the consumable products that is found around us.

Figure 1: A 3D Structural Representation Of Indigo Carmine Using WebMO (Calculation: Geometry Optimization, Theory: Hartree Fork, Basis Set: 6-31G(d))

Even though dyes like IC make consumable products look attractive we must be inquisitive about the amount and concentrations that we ingest into our bodies and how frequently that we can in order to have better diets to live healthier lives.

Method

Indigo Carmine (IC) powder obtained from Sigma Aldrich was measured with an analytical balance. The measured powder of IC was mixed with RO water with a stir bar to obtain a stock solution, put in a vial, and then calculated and recorded the concentration. The stock solution was diluted to obtain the first using dilution calculations to bring the concentration of the first dilution to half of the stock solution. An amount of the first dilution was taken using a pipette and put in another vial with the corresponding amount of water added to make the concentration ½ of the concentration of what the first dilution was. This process was repeated with every new dilution made until there were five dilutions and each dilution being half the concentration of what the previous dilution was. Each solution (stock solution and five dilutions from stock solution) were measured and wavelengths with corresponding absorbance recorded on the UV-Vis spectrophotometer. These same solutions were also taken to the HPLC to have their absorbance measured and then recorded. Using the absorbance measured and calculated concentrations recorded from the UV-Vis spectrophotometer, a graph of concentration vs absorbance was made and then by finding the slope of the curve was able to find the molar absorptivity of IC.

Figure 2: Indigo Carmine solutions prepared from stock solution to dilution 5

Results

Figure 3: Wavelength vs absorbance graph of different concentrations of IC

Figure 3.1: Wavelength vs absorbance of concentrations of IC used to calculate Molar absorptivity

Figure 3.2: Concentration vs absorbance graph of IC concentrations used to calculate molar absoptivity

Figure 3.4: HPLC graph of all concentrations of IC prepared