포도당의 비색 정량

DNS법으로 혈당 유사물 측정하기

Colorimetry Intermediate (High School) 60 분 ~$10.00

목표

다이나이트로살리실산(DNS) 비색법으로 포도당 농도를 결정하고 환원당 화학을 이해한다.

배경

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.

안전 경고

  • 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

필수 개인 보호 장비

goggles gloves lab_coat

재료

  • 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)

장비

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

실험 절차

1

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

10 분
2

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

5 분 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 분 Use tongs for hot tubes
4

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

2 분
5

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

5 분
6

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

15 분
7

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

18 분

예상 결과

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.

정리

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

세부 정보

카테고리
Colorimetry
난이도
Intermediate (High School)
소요 시간
60 분
예상 비용
$10.00
단계
7
재료
4

더 많은 실험

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Frequently Asked Questions

What is the objective of 포도당의 비색 정량?
다이나이트로살리실산(DNS) 비색법으로 포도당 농도를 결정하고 환원당 화학을 이해한다.
How difficult is 포도당의 비색 정량?
This experiment is rated as Intermediate (High School). It takes approximately 60 minutes to complete.
What safety precautions are needed for 포도당의 비색 정량?
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 포도당의 비색 정량?
The main materials required are: DNS reagent, Glucose stock solution, Unknown sugar solution, Distilled water.
What results should I expect from 포도당의 비색 정량?
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.