Spectrophotometry Lab Simulator

Simultaneous Determination of Two Dyes in Solution

This simulator guides students through baseline collection, calibration measurements, calibration-curve fitting, unknown-mixture analysis, and final evaluation.

Instructions

How to Use This App

Work through the steps in order. Data collected in each stage is carried forward into the next one.

Step 1

Baseline Setup

Since this simulation uses a single-beam instrument, you must measure the dark current and 100%T signals (in volts, in this case) for the red and green wavelengths. Once these are measured, you can move on to step 2: Collection of Callibration Data

Step 2

Calibration Data

In this step, you will prepare dye dilutions, spanning an approriate range of values. For each dilution, you will measure sample, and determine the signal voltage, from which the app will calculate %T and absorbance. At this point, you are ready to move on to step 3: Create the calibration curves.

Step 3

Calibration Curves

Here, you will select from your data, the points to be included in each of the cour calibration curves you must create. Once selected, you will build the four calibration plots, and fit each selected dataset to a line. Once completed, you are ready to measure your unknown solution.

Step 4

Unknown Mixture

Measure an unknown mixture at both wavelengths and determine the concentration of each dye based on the calibration data you fit in Step 3.

Step 5

Evaluation

Compare your reported concentrations with the actual values and see how everything worked. What might account for your % error?

Getting Started

Begin with Step 1 to collect the dark current and 100%T voltages. Those values are required for all later calculations.

Go to Step 1