분광광도법으로 아스피린 정량

UV 흡수로 시판 정제의 아스피린 함량 측정하기

Colorimetry Advanced (University) 75 분 ~$10.00

목표

가수분해 후 살리실산 이온으로서 UV 분광광도법을 사용하여 시판 정제의 아세틸살리실산(아스피린) 양을 결정한다.

배경

Aspirin (acetylsalicylic acid) can be quantified by first hydrolyzing it to salicylic acid, which forms an intensely purple complex with iron(III) chloride. This complex absorbs strongly at 530 nm. By comparing the absorbance of hydrolyzed tablet solutions with a calibration curve of standard salicylic acid solutions, students determine whether commercial tablets contain the labeled amount of aspirin.

안전 경고

  • NaOH and HCl are corrosive
  • Do not ingest any laboratory samples
  • FeCl₃ stains skin and clothing
  • Handle hot solutions with care

필수 개인 보호 장비

goggles gloves lab_coat

재료

  • Aspirin tablets (commercial) (3 tablets)
    325 mg or 500 mg labeled
  • Salicylic acid standard (1 g)
    For calibration
  • Iron(III) chloride (FeCl₃) solution (1%) (100 mL)
    Color reagent
  • NaOH (1M) (50 mL)
    For hydrolysis
  • HCl (1M) (50 mL)
    For acidification
  • Distilled water (500 mL)

장비

Spectrophotometer Cuvettes Volumetric flasks (100 mL, 8 total) Hot plate or water bath Mortar and pestle Analytical balance Filter paper and funnel

실험 절차

1

Prepare salicylic acid standards: 0, 5, 10, 20, 30, 40 ppm in 100 mL volumetric flasks.

10 분
2

Crush one aspirin tablet and dissolve in 10 mL of 1M NaOH. Heat gently on a water bath for 15 minutes to hydrolyze the ester bond.

20 분 Handle hot solution carefully
3

Cool the solution, acidify with 10 mL of 1M HCl, and filter into a 100 mL volumetric flask. Dilute to an expected concentration within the calibration range.

10 분
4

Add 5 mL of 1% FeCl₃ solution to each standard and sample flask. A purple color develops.

5 분
5

Allow 5 minutes for full color development. Measure absorbance at 530 nm, blanking with the 0 ppm standard.

15 분
6

Plot the calibration curve. Determine the salicylic acid concentration in the tablet solution, then calculate back to the original aspirin mass (accounting for hydrolysis stoichiometry and dilution).

15 분

예상 결과

The calibration curve should be linear. The calculated aspirin content should be close to the labeled amount (typically 95–105% of the stated dose). The purple FeCl₃ complex confirms salicylate presence.

정리

Neutralize acid/base waste before disposal. Collect FeCl₃ waste separately. Rinse all glassware thoroughly.

세부 정보

카테고리
Colorimetry
난이도
Advanced (University)
소요 시간
75 분
예상 비용
$10.00
단계
6
재료
6

더 많은 실험

분광광도법으로 식품 색소 분석 60 min 혼합물의 분광광도법 분석 75 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 분광광도법으로 아스피린 정량?
가수분해 후 살리실산 이온으로서 UV 분광광도법을 사용하여 시판 정제의 아세틸살리실산(아스피린) 양을 결정한다.
How difficult is 분광광도법으로 아스피린 정량?
This experiment is rated as Advanced (University). It takes approximately 75 minutes to complete.
What safety precautions are needed for 분광광도법으로 아스피린 정량?
Key safety precautions include: NaOH and HCl are corrosive; Do not ingest any laboratory samples; FeCl₃ stains skin and clothing.
What materials are needed for 분광광도법으로 아스피린 정량?
The main materials required are: Aspirin tablets (commercial), Salicylic acid standard, Iron(III) chloride (FeCl₃) solution (1%), NaOH (1M), HCl (1M).
What results should I expect from 분광광도법으로 아스피린 정량?
The calibration curve should be linear. The calculated aspirin content should be close to the labeled amount (typically 95–105% of the stated dose). The purple FeCl₃ complex confirms salicylate presence.