혼합물의 분광광도법 분석

연립 방정식으로 이성분 혼합물 분해하기

Colorimetry Advanced (University) 75 분 ~$12.00

목표

두 파장에서의 흡광도 측정과 연립 방정식으로 혼합 용액 속 두 가지 색소의 개별 농도를 결정한다.

배경

When a solution contains two absorbing species with overlapping spectra, a single wavelength measurement cannot determine both concentrations. However, by measuring absorbance at two wavelengths (ideally the λmax of each component) and applying the additive property of absorbance (Beer-Lambert), a system of two simultaneous equations can be solved. This technique is the basis of multicomponent analysis in spectrophotometry.

안전 경고

  • Indicator dyes stain clothing
  • Handle cuvettes by frosted sides only to avoid fingerprints
  • Clean spills immediately

필수 개인 보호 장비

goggles lab_coat

재료

  • Methyl orange solution (0.01%) (100 mL)
    Component A
  • Bromothymol blue solution (0.01%) (100 mL)
    Component B
  • Unknown mixture of both dyes (50 mL)
    Prepared by instructor
  • Distilled water (200 mL)

장비

UV-Vis spectrophotometer Cuvettes (matched pair) Volumetric flasks (50 mL, 6 total) Pipettes Calculator

실험 절차

1

Scan pure methyl orange from 350–700 nm. Record λmax (approximately 464 nm in acidic pH).

8 분
2

Scan pure bromothymol blue from 350–700 nm. Record λmax (approximately 615 nm at neutral pH).

7 분
3

Prepare 3 standard concentrations of each pure dye. Measure absorbance of each at both λmax values (464 and 615 nm).

15 분
4

Calculate the molar absorptivity (ε) for each dye at each wavelength from the standard curves: ε(A,464), ε(A,615), ε(B,464), ε(B,615).

15 분
5

Measure the absorbance of the unknown mixture at both wavelengths.

5 분
6

Set up the simultaneous equations: A(464) = ε(A,464)·C(A) + ε(B,464)·C(B), A(615) = ε(A,615)·C(A) + ε(B,615)·C(B). Solve for C(A) and C(B).

15 분
7

Verify your results by comparing the calculated total absorbance at several wavelengths with the measured mixture spectrum.

10 분

예상 결과

The simultaneous equations yield positive concentrations for both dyes. The reconstructed spectrum (sum of individual contributions) should closely match the measured mixture spectrum, validating the Beer-Lambert additivity principle.

정리

Pour dilute dye solutions down the drain with running water. Rinse all cuvettes and volumetric flasks thoroughly.

세부 정보

카테고리
Colorimetry
난이도
Advanced (University)
소요 시간
75 분
예상 비용
$12.00
단계
7
재료
4

더 많은 실험

분광광도법으로 아스피린 정량 75 min 분광광도법으로 식품 색소 분석 60 min 인산염의 비색 정량 90 min 포도당의 비색 정량 60 min 람베르트-베어 법칙 검증 60 min 비색 단백질 정량(브래드퍼드법) 60 min 물 속 철 함량 결정 75 min

Frequently Asked Questions

What is the objective of 혼합물의 분광광도법 분석?
두 파장에서의 흡광도 측정과 연립 방정식으로 혼합 용액 속 두 가지 색소의 개별 농도를 결정한다.
How difficult is 혼합물의 분광광도법 분석?
This experiment is rated as Advanced (University). It takes approximately 75 minutes to complete.
What safety precautions are needed for 혼합물의 분광광도법 분석?
Key safety precautions include: Indicator dyes stain clothing; Handle cuvettes by frosted sides only to avoid fingerprints; Clean spills immediately.
What materials are needed for 혼합물의 분광광도법 분석?
The main materials required are: Methyl orange solution (0.01%), Bromothymol blue solution (0.01%), Unknown mixture of both dyes, Distilled water.
What results should I expect from 혼합물의 분광광도법 분석?
The simultaneous equations yield positive concentrations for both dyes. The reconstructed spectrum (sum of individual contributions) should closely match the measured mixture spectrum, validating the Beer-Lambert additivity principle.