Análise de Corantes Alimentares por Espectrofotometria

Identificação de corantes alimentares artificiais por seus espectros de absorção

Colorimetry Intermediate (High School) 60 min ~$8,00

Objetivo

Determinar a identidade e concentração de corantes alimentares artificiais em bebidas comerciais medindo seus espectros de absorção.

Contexto

Artificial food dyes have characteristic absorption spectra that serve as fingerprints for identification. FD&C Red No. 40 absorbs maximally at 504 nm, Blue No. 1 at 630 nm, and Yellow No. 5 at 428 nm. By scanning the absorption spectrum of a commercial beverage and comparing peak wavelengths with known dye spectra, students can identify which dyes are present and estimate their concentrations.

Avisos de segurança

  • Food dyes can stain clothing
  • Do not drink any samples after use in the lab
  • Handle cuvettes by the frosted sides only

EPI necessário

goggles lab_coat

Materiais

  • Standard food dye solutions (50 mL each)
    Red 40, Blue 1, Yellow 5 (0.01%)
  • Commercial beverages (50 mL each)
    2–3 colored drinks
  • Distilled water (200 mL)
    For dilutions and blank

Equipamentos

UV-Vis spectrophotometer (or colorimeter with multiple filters) Cuvettes (quartz or plastic) Pipettes Volumetric flasks (25 mL, 4 total)

Procedimento

1

If using a spectrophotometer, scan each standard dye solution from 400 to 700 nm to identify the λmax (wavelength of maximum absorbance).

10 min
2

Record the λmax for each standard: Red 40 (≈504 nm), Blue 1 (≈630 nm), Yellow 5 (≈428 nm).

5 min
3

Dilute commercial beverage samples if too concentrated (absorbance should be below 1.0). Record all dilution factors.

10 min
4

Scan each beverage sample from 400 to 700 nm. Record the absorption spectrum.

15 min
5

Compare the beverage absorption peaks with the standard dye λmax values to identify which dyes are present.

10 min
6

If a calibration curve was prepared for a specific dye, calculate the dye concentration in each beverage (accounting for dilution).

10 min

Resultados esperados

Each beverage should show absorption peaks matching one or more standard food dyes. Green drinks typically contain both Blue 1 and Yellow 5. Orange drinks often contain Red 40 and Yellow 5.

Limpeza

Pour dilute dye solutions down the drain with running water. Rinse cuvettes immediately to prevent staining.

Detalhes

Categoria
Colorimetry
Dificuldade
Intermediate (High School)
Duração
60 min
Custo estimado
$8,00
Passos
6
Materiais
3

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Frequently Asked Questions

What is the objective of Análise de Corantes Alimentares por Espectrofotometria?
Determinar a identidade e concentração de corantes alimentares artificiais em bebidas comerciais medindo seus espectros de absorção.
How difficult is Análise de Corantes Alimentares por Espectrofotometria?
This experiment is rated as Intermediate (High School). It takes approximately 60 minutes to complete.
What safety precautions are needed for Análise de Corantes Alimentares por Espectrofotometria?
Key safety precautions include: Food dyes can stain clothing; Do not drink any samples after use in the lab; Handle cuvettes by the frosted sides only.
What materials are needed for Análise de Corantes Alimentares por Espectrofotometria?
The main materials required are: Standard food dye solutions, Commercial beverages, Distilled water.
What results should I expect from Análise de Corantes Alimentares por Espectrofotometria?
Each beverage should show absorption peaks matching one or more standard food dyes. Green drinks typically contain both Blue 1 and Yellow 5. Orange drinks often contain Red 40 and Yellow 5.