Анализ пищевых красителей спектрофотометрией

Идентификация искусственных пищевых красителей по спектрам поглощения

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

Цель

Определить состав и концентрацию искусственных пищевых красителей в коммерческих напитках, измеряя их спектры поглощения.

Предпосылки

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.

Предупреждения по безопасности

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

Требуемые СИЗ

goggles lab_coat

Материалы

  • 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

Оборудование

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

Процедура

1

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

10 мин
2

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

5 мин
3

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

10 мин
4

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

15 мин
5

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

10 мин
6

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

10 мин

Ожидаемые результаты

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.

Уборка

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

Детали

Категория
Colorimetry
Сложность
Intermediate (High School)
Продолжительность
60 мин
Прим. стоимость
$8,00
Шаги
6
Материалы
3

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Frequently Asked Questions

What is the objective of Анализ пищевых красителей спектрофотометрией?
Определить состав и концентрацию искусственных пищевых красителей в коммерческих напитках, измеряя их спектры поглощения.
How difficult is Анализ пищевых красителей спектрофотометрией?
This experiment is rated as Intermediate (High School). It takes approximately 60 minutes to complete.
What safety precautions are needed for Анализ пищевых красителей спектрофотометрией?
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 Анализ пищевых красителей спектрофотометрией?
The main materials required are: Standard food dye solutions, Commercial beverages, Distilled water.
What results should I expect from Анализ пищевых красителей спектрофотометрией?
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.