分光光度法分析食品染料

用吸收光谱鉴定人工食品色素

Colorimetry Intermediate (High School) 60 分钟 ~$8.00

目标

通过测量吸收光谱，测定商业饮料中人工食品色素的种类和浓度。

背景

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.

安全警告

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

所需PPE

goggles lab_coat

材料

  • 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

设备

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

步骤

1

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

10 分钟
2

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

5 分钟
3

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

10 分钟
4

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

15 分钟
5

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

10 分钟
6

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

10 分钟

预期结果

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.

清理

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

详情

类别
Colorimetry
难度
Intermediate (High School)
时长
60 分钟
预估费用
$8.00
步骤数
6
材料
3

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Frequently Asked Questions

What is the objective of 分光光度法分析食品染料?
通过测量吸收光谱，测定商业饮料中人工食品色素的种类和浓度。
How difficult is 分光光度法分析食品染料?
This experiment is rated as Intermediate (High School). It takes approximately 60 minutes to complete.
What safety precautions are needed for 分光光度法分析食品染料?
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 分光光度法分析食品染料?
The main materials required are: Standard food dye solutions, Commercial beverages, Distilled water.
What results should I expect from 分光光度法分析食品染料?
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.