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Trial Number 16

Client Number 108

Project Number 1

Trial Purpose:

To measure contamination levels of cleaning solution over five days of use.

Date Run:

10/08/1999

Experiment Procedure:

A 2% solution was made of Micro 90 using DI water in 400 mL beaker. Three concentrations of the contaminant, based on volume percent (5, 10 and 15), were added to separate 80 mL beakers and containing the cleaner. Using LaMotte’s Smart Colorimeter to evaluate the standards using the chlorine test. The general test procedure was first to zero the instrument using 0% standard (2% Micro 90). The other standards were measured and values were recorded. The vial was rinsed in between each standard in order to ensure accurate readings. Once the standards were measured, the five unknown samples were analyzed. Using the recorded values, the data was plotted and analyzed using statistical methods available in Microsoft Excel.

Unknown concentrations were calculated from the new standards made and from the old correlation determined in a previous trial. This was done to determine if standards had to be made up every time or if one correlation could be used instead.

SUBSTRATE MATERIAL: Liquid-Dirty Cleaning Solution
CONTAMINANTS: DuPont Evanol Concentrated (Vinyl Alcohol Polymers & Copolymers CAS#s: 9002-89-5, 25213-24-5, 54626-91-4; Methanol Bulk/Packaged CAS #: 67-56-1; Sodium Acetate CAS#: 127-09-3)

Trial Results:

The first portion of the experiment was to determine a formula which could be used to calculate the concentrations of the unknown samples. Table 1 list the standard concentrations, the readings recorded and calculated data using new and old correlations.

Table 1. Correlations

  Baseline Calculated x = (y-b)/m
Evanol % New Trial 6 Trial 15 Trial 17
0 0 0.005 -0.001 -0.008
5 0.02 0.04 0.033 0.034
10 0.08 0.075 0.067 0.076
15 0.12 0.11 0.101 0.118
50 0.355 0.339 0.412  

Using the two formulas, the unknown concentrations were determined after rearranging the formulas to solve for the concentrations. Table 2 lists the sample date, the recorded chlorine concentrations and the three calculated contaminant concentrations. These values could also be obtained graphically as shown in Figure 1. As can be seen both from Figure 1 and Table 2, the two values obtained are relatively the same.

Table 2. Determination of Uknown Samples

Unknown Soil Loading x = (y-b)/m      
  Sample Data Trial 6 Trial 15 Trial 17
29-Sep 0.2 27.86 29.56 24.76
1-Oct 0.13 17.86 19.26 16.43

The three equations developed over the various colorimeter experiments are listed in Table 3. The slopes and the y-intercepts are all relatively the same.

Table 3. Equations

Trial 6 = 0.007*x + 0.005
Trial 15 = 0.0068*x - 0.001
Trial 17 = 0.0084*x -0.008

Success Rating:

A cleanliness study, addressing only various analytical techniques.

Conclusion:

The unknown soil loading for the two samples were found using two methods. The formula method yielded a concentration of 25% for the September 29th reading and 16% for October 1st when using the correlation determined during trial 17.  The graphical method yield similar numbers.

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