グルコースの比色定量

DNS法で血糖アナログを測定する

Colorimetry Intermediate (High School) 60 分 ~$10.00

目的

ジニトロサリチル酸（DNS）比色法を用いてグルコース濃度を決定し、還元糖の化学を理解する。

背景

The DNS method is a classic colorimetric assay for reducing sugars. 3,5-dinitrosalicylic acid (yellow) is reduced by the free aldehyde group of glucose to 3-amino-5-nitrosalicylic acid (orange-red). The color change occurs upon heating, and the intensity at 540 nm is proportional to the reducing sugar concentration. This method is widely used in food science and fermentation monitoring.

安全上の警告

  • DNS reagent contains NaOH — corrosive to skin
  • Boiling water bath — handle tubes with tongs
  • Cool tubes before opening to prevent splattering
  • DNS reagent stains skin yellow

必要なPPE

goggles gloves lab_coat

材料

  • DNS reagent (100 mL)
    1% DNS in NaOH with sodium potassium tartrate
  • Glucose stock solution (100 mL)
    10 mg/mL in water
  • Unknown sugar solution (20 mL)
  • Distilled water (200 mL)

器具

Spectrophotometer or colorimeter Cuvettes Boiling water bath Test tubes (10) with caps Pipettes (1 mL, 5 mL) Ice bath Timer

手順

1

Prepare glucose standards: 0, 1, 2, 4, 6, 8, 10 mg/mL by diluting the stock solution.

10 分
2

Add 1 mL of each standard and the unknown to labeled test tubes. Add 1 mL of DNS reagent to each tube.

5 分 DNS contains NaOH
3

Place all tubes in a boiling water bath for exactly 5 minutes. The color changes from yellow to orange-red.

5 分 Use tongs for hot tubes
4

Transfer tubes immediately to an ice bath to stop the reaction. Cool for 2 minutes.

2 分
5

Add 8 mL of distilled water to each tube and mix well.

5 分
6

Measure absorbance at 540 nm. Zero with the blank (0 mg/mL glucose).

15 分
7

Plot the calibration curve and determine the glucose concentration of the unknown.

18 分

予想される結果

A linear calibration curve from 1–10 mg/mL glucose. The color intensifies from pale yellow (blank) to deep orange-red (10 mg/mL). Non-reducing sugars like sucrose give no color change.

後片付け

Neutralize DNS waste with dilute HCl before disposal. Clean test tubes immediately as dried DNS residue is difficult to remove.

詳細

カテゴリ
Colorimetry
難易度
Intermediate (High School)
所要時間
60 分
推定費用
$10.00
ステップ数
7
材料
4

その他の実験

ランベルト-ベールの法則の検証 60 min リン酸塩の比色定量 90 min 分光光度法によるアスピリンの定量 75 min 分光光度法による食品着色料分析 60 min 比色タンパク質定量（Bradford法） 60 min 水中の鉄の定量 75 min 混合物の分光光度法分析 75 min

Frequently Asked Questions

What is the objective of グルコースの比色定量?
ジニトロサリチル酸（DNS）比色法を用いてグルコース濃度を決定し、還元糖の化学を理解する。
How difficult is グルコースの比色定量?
This experiment is rated as Intermediate (High School). It takes approximately 60 minutes to complete.
What safety precautions are needed for グルコースの比色定量?
Key safety precautions include: DNS reagent contains NaOH — corrosive to skin; Boiling water bath — handle tubes with tongs; Cool tubes before opening to prevent splattering.
What materials are needed for グルコースの比色定量?
The main materials required are: DNS reagent, Glucose stock solution, Unknown sugar solution, Distilled water.
What results should I expect from グルコースの比色定量?
A linear calibration curve from 1–10 mg/mL glucose. The color intensifies from pale yellow (blank) to deep orange-red (10 mg/mL). Non-reducing sugars like sucrose give no color change.