CHEM 10054 Experiment 3Experiment 3 Report Forms

Name

Student ID

Name

Student ID

At the start of the lab, show your completed pre-lab calculations to your instructor and obtain the

instructors initials.

Instructor Initials: ________________

Pre-Lab Calculations

Calculate the volume (mL) of 100.0 ppm food dye solution that is required to prepare 50.0 mL of 10.00

ppm food dye solution. Report your answer to 2 decimal places. Please show your work.

Volume of 100.0 ppm food dye solution =_____________mL

Results

Part A: Determination of the absorptivity and molar absorptivity of a food dye

Name and concentration of a food dye solution:____________________ & ________ ppm

Calculate the absorptivity and molar absorptivity of the food dye and determine the mean, standard

deviation and 95% confidence interval for molar absorptivity. Show your work on the next page.

Table 1. Absorbance, Absorptivity “𝑎” and molar absorptivity “𝜀” for a food dye

value

repeat absorbance measurements and absorptivity calculations

corrected

absorbance

𝑎

(ppm–1 ∙ cm–1)

𝜀

–1

(L mol ∙ cm–1 )

average 𝜀

(L mol–1∙ cm–1 )

standard

deviation of 𝜀

(L mol–1∙ cm–1 )

95% confidence

interval of 𝜀

(L mol–1∙ cm–1 )

Page 1 of 5

CHEM 10054 Experiment 3

The absorptivity “a” in units of L mg–1·cm–1 using 𝐴 = 𝑎𝑏𝑐 where 𝑏 is the path length in cm and 𝑐 is the

food dye concentration in ppm. Show a sample calculation.

The molar absorptivity “” in units of L mol–1·cm–1 using 𝐴 = 𝜀𝑏𝑐 where 𝑏 is the path length in cm and 𝑐 is

the food dye concentration in mol L–1. Note: Molar absorptivity can also be calculated by using this

equation: 𝜀 = 𝑎 × 1000 × 𝑀𝑀 where 𝑀𝑀 represents the molar mass of the food dye.

Calculate the 95% confidence interval with 𝑁 − 1 degrees of freedom for the molar absorptivity 𝜀.

𝑡𝑠

Hint: 𝑥̅ ±

where 𝑥̅ is the average value, 𝑠 is the standard deviation, 𝑁 is the number of data points

√𝑁

and 𝑡 is the value from the Student’s 𝑡-table at 𝑁 − 1 degrees of freedom.

Page 2 of 5

CHEM 10054 Experiment 3

Question 1: Is your average molar absorptivity 𝜀 accurate at the 95% confidence level? For this

calculation, you will need the literature or true value (𝜇𝑜 ; refer to the table in the introduction for this

value). Show a sample calculation.

Hint: 𝑡𝑐𝑎𝑙𝑐 =

|𝑥̅ −𝜇𝑜 |

𝑠

× √𝑁 and if 𝑡𝑐𝑎𝑙𝑐 > 𝑡𝑡𝑎𝑏𝑙𝑒 , then the results are statistically different.

Part B: Determination of the dilution factor for the unknown

Table 2. Mass of the unknown.

Unknown #

Mass vial + sample

Mass vial (dry)

Mass sample

= ___________

= ____________ g

= _____________ g

= ____________ g

Table 3. Determine the dilution factor for standard addition.

Trial #

Volume of the

unknown solution

(mL)

Volume of the

volumetric flask

(mL)

e.g.,

10.00

50.00

Absorbance

Dilution factor

50.00/10.00 = 5.00

1

2

3

4

Note: From the correct trial, you will use the volume of the unknown and the volume of the volumetric

flask for the remainder of the experiment.

Page 3 of 5

CHEM 10054 Experiment 3

Part C: Standard Addition Experiment

Table 4: Preparation and Absorbance Readings for Standard Addition Solutions.

Flask

Unknown

Sample

Volume

(mL)

e.g.

10.00

1

Volume of 100.0 ppm Food Dye Solution Added

(mL)

Volume Added

Final

Initial

1.21

0.20

Concentration of

Food Dye Added

Cadded

(ppm)

Blank-Corrected

Absorbance

2.02

0.510

1.01

0.00 mL food dye solution added

0.00

2

3

4

5

6

Plot and submit a graph of the absorbance (𝑦-axis) versus concentration of food dye (ppm) added (𝑥axis) using the data from Table 4. Calculate the equation of best straight line (linear least squares line

equation). Report the slope and y-intercept for this line. Attach the standard addition curve to this report

or submit it to the Dropbox.

Table 5: Analysis of standard addition curve

𝑚 = slope = ______________

𝐵⁄ = _____________

𝑚

𝐵 = intercept = ___________

Dilution factor = ____________

R2 = ___________

Use the standard addition curve data, to find the unknown concentration of food dye in the original

unknown sample (prepared from the coloured drink powder in the 100.0 mL volumetric flask). Show

your calculation.

[food dye] = ___________________ ppm

Page 4 of 5

CHEM 10054 Experiment 3

Calculate the mass of the food dye in the unknown in the 100.0 mL flask.

Mass food dye = _________________ g

Calculate the %(w/w) food dye in the unknown sample.

Unknown # = ________________

%(w/w) food dye = ____________ %

Calculate the % spike recovery using the absorbance data from flask 1 and 2 and the slope of the standard

addition curve.

% spike recovery = _______________%

Question #2: What does the % spike recovery indicate about this experiment?

Page 5 of 5

CHEM 10054 Experiment 3

Experiment 3 Report Forms

Name

Student ID

Name

Student ID

At the start of the lab, show your completed pre-lab calculations to your instructor and obtain the

instructors initials.

Instructor Initials: ________________

Pre-Lab Calculations

Calculate the volume (mL) of 100.0 ppm food dye solution that is required to prepare 50.0 mL of 10.00

ppm food dye solution. Report your answer to 2 decimal places. Please show your work.

Volume of 100.0 ppm food dye solution =_____________mL

Results

Part A: Determination of the absorptivity and molar absorptivity of a food dye

Name and concentration of a food dye solution:____________________ & ________ ppm

Calculate the absorptivity and molar absorptivity of the food dye and determine the mean, standard

deviation and 95% confidence interval for molar absorptivity. Show your work on the next page.

Table 1. Absorbance, Absorptivity “𝑎” and molar absorptivity “𝜀” for a food dye

value

repeat absorbance measurements and absorptivity calculations

corrected

absorbance

𝑎

(ppm–1 ∙ cm–1)

𝜀

–1

(L mol ∙ cm–1 )

average 𝜀

(L mol–1∙ cm–1 )

standard

deviation of 𝜀

(L mol–1∙ cm–1 )

95% confidence

interval of 𝜀

(L mol–1∙ cm–1 )

Page 1 of 5

CHEM 10054 Experiment 3

The absorptivity “a” in units of L mg–1·cm–1 using 𝐴 = 𝑎𝑏𝑐 where 𝑏 is the path length in cm and 𝑐 is the

food dye concentration in ppm. Show a sample calculation.

The molar absorptivity “” in units of L mol–1·cm–1 using 𝐴 = 𝜀𝑏𝑐 where 𝑏 is the path length in cm and 𝑐 is

the food dye concentration in mol L–1. Note: Molar absorptivity can also be calculated by using this

equation: 𝜀 = 𝑎 × 1000 × 𝑀𝑀 where 𝑀𝑀 represents the molar mass of the food dye.

Calculate the 95% confidence interval with 𝑁 − 1 degrees of freedom for the molar absorptivity 𝜀.

𝑡𝑠

Hint: 𝑥̅ ±

where 𝑥̅ is the average value, 𝑠 is the standard deviation, 𝑁 is the number of data points

√𝑁

and 𝑡 is the value from the Student’s 𝑡-table at 𝑁 − 1 degrees of freedom.

Page 2 of 5

CHEM 10054 Experiment 3

Question 1: Is your average molar absorptivity 𝜀 accurate at the 95% confidence level? For this

calculation, you will need the literature or true value (𝜇𝑜 ; refer to the table in the introduction for this

value). Show a sample calculation.

Hint: 𝑡𝑐𝑎𝑙𝑐 =

|𝑥̅ −𝜇𝑜 |

𝑠

× √𝑁 and if 𝑡𝑐𝑎𝑙𝑐 > 𝑡𝑡𝑎𝑏𝑙𝑒 , then the results are statistically different.

Part B: Determination of the dilution factor for the unknown

Table 2. Mass of the unknown.

Unknown #

Mass vial + sample

Mass vial (dry)

Mass sample

= ___________

= ____________ g

= _____________ g

= ____________ g

Table 3. Determine the dilution factor for standard addition.

Trial #

Volume of the

unknown solution

(mL)

Volume of the

volumetric flask

(mL)

e.g.,

10.00

50.00

Absorbance

Dilution factor

50.00/10.00 = 5.00

1

2

3

4

Note: From the correct trial, you will use the volume of the unknown and the volume of the volumetric

flask for the remainder of the experiment.

Page 3 of 5

CHEM 10054 Experiment 3

Part C: Standard Addition Experiment

Table 4: Preparation and Absorbance Readings for Standard Addition Solutions.

Flask

Unknown

Sample

Volume

(mL)

e.g.

10.00

1

Volume of 100.0 ppm Food Dye Solution Added

(mL)

Volume Added

Final

Initial

1.21

0.20

Concentration of

Food Dye Added

Cadded

(ppm)

Blank-Corrected

Absorbance

2.02

0.510

1.01

0.00 mL food dye solution added

0.00

2

3

4

5

6

Plot and submit a graph of the absorbance (𝑦-axis) versus concentration of food dye (ppm) added (𝑥axis) using the data from Table 4. Calculate the equation of best straight line (linear least squares line

equation). Report the slope and y-intercept for this line. Attach the standard addition curve to this report

or submit it to the Dropbox.

Table 5: Analysis of standard addition curve

𝑚 = slope = ______________

𝐵⁄ = _____________

𝑚

𝐵 = intercept = ___________

Dilution factor = ____________

R2 = ___________

Use the standard addition curve data, to find the unknown concentration of food dye in the original

unknown sample (prepared from the coloured drink powder in the 100.0 mL volumetric flask). Show

your calculation.

[food dye] = ___________________ ppm

Page 4 of 5

CHEM 10054 Experiment 3

Calculate the mass of the food dye in the unknown in the 100.0 mL flask.

Mass food dye = _________________ g

Calculate the %(w/w) food dye in the unknown sample.

Unknown # = ________________

%(w/w) food dye = ____________ %

Calculate the % spike recovery using the absorbance data from flask 1 and 2 and the slope of the standard

addition curve.

% spike recovery = _______________%

Question #2: What does the % spike recovery indicate about this experiment?

Page 5 of 5

CHEM 10054 Experiment 7

Experiment 7 Report Forms

Name

Student ID

Name

Student ID

At the start of the lab, show your completed pre-lab calculations to your instructor and obtain the

instructors initials.

Instructor Initials: ________________

Pre-Lab Calculations

Calibration Standard Preparation: Using three (3) volumetric flasks, prepare 50.00 mL of 10.0 ppm,

50.00 ppm and 100.0 ppm of a mixed Na, K, and Ca standard. What volume of 1000.0 ppm stock metal

standard is required to prepare the calibration standards?

Table 1. Target metal ion (Na, K, Ca) concentration preparations for calibration standards.

Stock Concentration

Aliquot Volume

Target Concentration

Flask Volume

(ppm Metal ion)

(mL)

(ppm Metal ion)

(mL)

C1

V1

C2

V2

1

1000.0

10.00

50.0

2

1000.0

50.00

50.0

3

1000.0

100.00

50.0

Show a sample calculation.

Spiked Sample Preparation: You will analyze a diluted milk sample, but you will also need to perform

a spike recovery calculation (i.e., you will add a known volume of 1000.0 ppm metal ion stock) to your

unknown. The spiked concentration to the unknown is C2 or Cadded. Calculate the volume of 1000.0 ppm

stock to be added to 50.0 mL volumetric flask to produce C2 or Cadded concentrations of 20.00 ppm metal

ion.

Stock Concentration

(ppm metal ion)

C1

1000.0

Aliquot Volume

(mL)

V1

Target Concentration

(ppm metal ion)

C2 or Cadded

Flask Volume

(mL)

V2

20.00

50.0

Page 1 of 5

CHEM 10054 Experiment 7

Results

Record the determined concentrations for the analysis without the addition of La and those with La.

Indicate which data was collected by you and your lab partner. Attached the printed results of your

analysis to this report.

Data collected by you and your lab partner: without La or with La

(circle which applies)

Table 1: Complete the following table for the determined metal ion concentration.

Cup #

Sample

Na

ppm

K

ppm

Ca

ppm

Results without La

4

Diluted Milk Sample 1

5

Diluted Milk Sample 2

6

Diluted Milk Sample 3

7

Diluted Milk Sample 4 + spike

8

Blank – distilled water

9

50.00 ppm mixed calibration (Na, K, Ca)

Results with La

4

Diluted Milk Sample 1

5

Diluted Milk Sample 2

6

Diluted Milk Sample 3

7

Diluted Milk Sample 4 + spike

8

Blank – distilled water

9

50.00 ppm mixed calibration (Na, K, Ca)

Page 2 of 5

CHEM 10054 Experiment 7

Determine the average and standard deviation of the metal ion concentrations in the diluted milk

samples. Calculate the %spike recovery for each metal ion. Show a sample calculation.

Table 2: Metal ion concentration in diluted milk samples used to calculate %spike recovery.

Na

ppm

Results

K

ppm

Ca

ppm

without La

Average 𝐶𝑜𝑟𝑖𝑔𝑖𝑛𝑎𝑙 (ppm)

Standard Deviation 𝐶𝑜𝑟𝑖𝑔𝑖𝑛𝑎𝑙 (ppm)

%Spike Recovery =

with La

Average 𝐶𝑜𝑟𝑖𝑔𝑖𝑛𝑎𝑙 (ppm)

Standard Deviation 𝐶𝑜𝑟𝑖𝑔𝑖𝑛𝑎𝑙 (ppm)

%Spike Recovery =

Hint: %𝑠𝑝𝑖𝑘𝑒 𝑟𝑒𝑐𝑜𝑣𝑒𝑟𝑦 =

𝐶𝑠𝑝𝑖𝑘𝑒 −𝐶𝑜𝑟𝑖𝑔𝑖𝑛𝑎𝑙

𝐶𝑎𝑑𝑑𝑒𝑑

× 100%

Question 1: Are there any anomalous %spike recovery values? What do the anomalous %spike

recovery values indicate about the analysis?

Question 2: How do the %spike recovery values compare between the results obtained for the samples

with La and those without La? What does this indicate about the analysis?

Page 3 of 5

CHEM 10054 Experiment 7

Calculate the average metal ion concentration (ppm) in milk. Remember to include the dilution factor. If

the %spike recovery is below 75% or greater than 125%, then do not report the concentration of the

ion, but report as N/A. Show a sample calculation.

Your instructor will provide you with the actual metal ion concentration in your milk sample. Enter these

in the table below.

Table 3: Metal ion content in the milk samples.

Na

ppm

Sample

K

ppm

Ca

ppm

Milk Sample (without La)

Milk Sample (with La)

Actual

Calculate the %relative error for each metal ion, when possible. Show a sample calculation.

Table 4: %Relative Error in metal ion concentration.

Na

ppm

Sample

K

ppm

Ca

ppm

%relative error (without La) =

%relative error (with La) =

Hint: %𝑟𝑒𝑙𝑎𝑡𝑖𝑣𝑒 𝑒𝑟𝑟𝑜𝑟 =

𝑒𝑥𝑝.𝑣𝑎𝑙𝑢𝑒−𝑡𝑟𝑢𝑒 𝑣𝑎𝑙𝑢𝑒

𝑡𝑟𝑢𝑒 𝑣𝑎𝑙𝑢𝑒

× 100%

Question 3: What do these results imply about the sample matrices in this analysis?

Page 4 of 5

CHEM 10054 Experiment 7

Calculate the %relative error for each metal ion in the calibration check.

Table 5: Calibration check results.

Sample

Na

ppm

K

ppm

Ca

ppm

50.00 ppm standard (without La)

50.00 ppm standard (with La)

%relative error (without La) =

%relative error (with La) =

Question 4: How well did the BWB Flame Photometer hold its calibration?

Page 5 of 5

CHEM 10054 Experiment 9

Experiment 9 Report Forms

Name

Student ID

Name

Student ID

At the start of the lab, show your completed pre-lab calculations to your instructor and obtain the

instructors initials.

Instructor Initials: ________________

Pre-Lab Calculations

Calculate the concentration of caffeine prepared from a 1000 ppm caffeine stock solution if the following

aliquots are diluted into a 10.00 mL volumetric flask.

Table 1. Dilutions for the preparation of caffeine standards.

Stock Caffeine

Aliquot Vol. of Stock

Total volume

V1 (L)

C1 (ppm)

V2 (mL)

1

1000

100

10.00

2

1000

250

10.00

3

1000

350

10.00

4

1000

500

10.00

Caffeine Conc.

C2 (ppm)

If a 500 L aliquot of your sample is diluted to 10.00 mL, the dilution factor is……

Dilution factor=________________

Results

Part A: Preparation and Analysis of Standard Solutions and Samples

Enter the concentration, retention time and peak area for the samples of milli-Q water, theophylline (flask

1), caffeine (flask 2) and adipic acid (flask 3).

Table 2. Summary table for HPLC data

Concentration

Flask

Compound

(ppm)

milli-Q water

1

caffeine

2

theophylline

3

adipic acid

Retention Time

(min)

Peak Area

(mAu∙s)

————-

Note: 1. The peak for milli Q water will be very small and around 2-2.26 min.

2. Please don’t panic if there are no peaks for flask 3 (adipic acid) or very small.

Page 1 of 4

CHEM 10054 Experiment 9

Enter the caffeine concentration of the standards and report caffeine and theophylline retention times

(tR), peak areas and peak widths.

Table 3. HPLC data for calibration caffeine standards and the unknown sample.

Caffeine

Conc.

(ppm)

Flask

#

tR

(min)

Caffeine

Area

(mAu∙s)

Width

(min)

tR

(min)

Theophylline

Area

(mAu∙s)

Width

(min)

Area Ratio

Acaf/Atheo

4

5

6

7

8

unknown

Prepare a calibration curve using external standards by plotting the peak area of caffeine as a function of

caffeine concentration and a calibration curve using an internal standard by plotting peak area ratios of

Acaffeine/Atheophylline as a function of caffeine concentration. Attach the calibration curves to your report or

submit to the Dropbox. Apply a trend line to the data and report the trend line equations and R2 values.

Note: Remember that these are not Beer’s law plots and as such the intercepts may not go through (0,0);

therefore, do not force the trend lines through (0,0).

Table 4. Calibration curve data and caffeine concentration in the unknown sample.

Parameter

External Standards

Internal Standard

regression equation

R2 value

Caffeine concentration in

the diluted sample (ppm)

Caffeine concentration in

the original sample (ppm)

Calculate the concentration of the caffeine unknown in diluted and original solutions. Remember to adjust

the FINAL concentration for any dilution factors. Show your work for either the external or internal

standard calibration curve.

diluted unknown caffeine concentration (ppm) =________________

original unknown caffeine concentration (ppm) =________________

Page 2 of 4

CHEM 10054 Experiment 9

Calculate the resolution 𝑅𝑠 of caffeine and theophylline (use one set of data from flask 4 to 7). Show your

calculation.

𝑅𝑠 =

2[𝑡𝑅 (𝑐𝑎𝑓𝑓𝑒𝑖𝑛𝑒) − 𝑡𝑅 (𝑡ℎ𝑒𝑜𝑝ℎ𝑦𝑙𝑙𝑖𝑛𝑒) ]

𝑤𝑐𝑎𝑓𝑓𝑒𝑖𝑛𝑒 + 𝑤𝑡ℎ𝑒𝑜𝑝ℎ𝑦𝑙𝑙𝑖𝑛𝑒

where 𝑡𝑅 is the retention time in minutes

𝑤 is the peak width in minutes

Calculate the capacity factor for theophylline (use one set of data from flask 4 to 7). Show your

calculation.

𝑐𝑎𝑝𝑎𝑐𝑖𝑡𝑦 𝑓𝑎𝑐𝑡𝑜𝑟 = 𝑘𝐴 = (

𝑡𝑅 − 𝑡𝑀

)

𝑡𝑀

where 𝑡𝑅 is the retention time for theophylline

𝑡𝑀 is the retention time for the solvent peak (~2.66 min)

Question 1: What does the capacity factor tells you about theophylline?

Part B: UV spectra of adipic acid, caffeine and theophylline

Attach the UV spectra for the caffeine, theophylline and adipic acid or submit them to the Dropbox.

Examine the spectra and absorbance data at 254 nm and record the absorbance at 254 nm.

Table 5. Absorbance data for 10.00 ppm caffeine, theophylline and adipic acid at 254 nm.

Compound/Analyte

Absorbance at 254 nm

adipic acid

caffeine

theophylline

Page 3 of 4

CHEM 10054 Experiment 9

Question 2: If the HPLC detector only measures the absorbance at 254 nm, is adipic acid a good choice

to be used as an internal standard? Use the HPLC and UV data (Tables 4 and 5) to answer this question.

Question 3: Are there any other reasons why adipic acid may not have been an ideal choice as an

internal standard?

Part C: Calibration of a micropipette

Table 6. Calibration of the micropipette

Target Volume

(L)

100

Mass 1

(g)

Mass 2

(g)

Mass 3

(g)

Average Volume

(L)

250

350

500

1000

Question 5: Based on your results, is the micropipette calibrated? If not, then would it lead to

incorrect/inaccurate results?

Page 4 of 4

EXPERIMENT 1: Data Analysis (Part A)

Table 1: Name and Student Number

Student Name

Siddharth Thanki

Student Number

859800

Third Last Digit (X)

8

Second Last Digit (Y)

1

Last Digit (Z)

1

Table 2: Stock Solution Data

Stock Solution

Units

Mass

0.3811

g

Molar Mass

158.1

g/mol

Volume of Stock Solution

0.5000

L

Concentration

762.2

ppm

% Transmittance

Absorbance

Conc. Blank

(%T)

Signal

(ppm)

Table 3: Blank Data

Repeat Measurements

1

98.8

0.00524

0.587

2

99.1

0.00393

0.440

3

99.1

0.00393

0.440

4

98.8

0.00524

0.587

5

99.1

0.00393

0.440

6

98.1

0.00833

0.933

7

99.8

0.00087

0.097

8

99.1

0.00393

0.440

9

99.8

0.00087

0.097

10

98.1

0.00833

0.933

Average:

99.0

0.00446

0.499

Standard Deviation:

0.6

0.00254

0.285

Table 4: Parameters to be Determined or Calculated

Parameters

Value

Unit

Slope of Linear Calibration Curve (m )

0.00893

1/ppm

Absorptivity (a )

0.00893

L/(mg*cm)

1412

L/(mol*cm)

Molar Absorptivity (Ɛ)

Detection limit: (cm)

0.854

ppm

Limit of Quantification (LOQ or cQ)

2.85

ppm

Method Detection Limit (MDL)

0.925

ppm

Signal-To-Noise (S/N ) for the blank

1.75

no unit

%RSD for the blank

57.0

no unit

EXPERIMENT 1: Data Analysis (Part B)

Table 5: Calibration Standards and Unknown Samples Data

Volume of Stock in

100.0 mL

Concentration

%

Transmittance

(mL)

(ppm)

(%T)

Blank

0.00

0.00

98.98

Standard 1

0.50

3.81

92.5

Standard 2

1.00

7.62

85.3

Standard 3

2.00

15.24

72.0

Standard 4

5.00

38.11

43.1

Standard 4

5.00

38.11

45.7

Standard 4

5.00

38.11

44.9

Standard 5

10.00

76.22

21.6

Standard 6

15.00

114.33

9.3

Standard 7

25.00

190.55

7.3

Sample #1

0.00

61.8

Sample #2

0.00

41.1

Solution

Table 6: Calibration Curve Data

Concentration

CorrectedAbsorbance

(ppm)

(Abs)

Blank

0.00

0.0000

Standard 1

3.81

0.0294

Standard 2

7.62

0.0643

Standard 3

15.24

0.1383

Standard 4

38.11

0.3609

Standard 4

38.11

0.3354

Standard 4

38.11

0.3432

Standard 5

76.22

0.6605

Standard 6

114.33

1.0274

sample

Standard 7

190.55

1.1312

Table 7: Parameters to be Determined or Calculated

Parameters

Value

Unit

Limit of Linearity (LOL)

114.33

ppm

Dynamic Range (LOL – LOQ)

111.48

ppm

Slope of Linear Calibration Curve (m )

0.00893

1/ppm

Calibration Sensitivity (m )

0.00893

1/ppm

Average Corrected-Absorbance Standard 4

0.3465

no unit

Std. Dev. Corrected-Absorbance Standard 4

0.01304

no unit

Analytical Sensitivity (𝛾) for Standard 4

0.6851

1/ppm

Signal-To-Noise (S/N ) for Standard 4

26.58

no unit

%RSD for Standard 4

3.762

no unit

Concentration Sample #1

22.9

ppm

Concentration Sample #2

42.8

ppm

Absorbance

CorrectedAbsorbance

(Abs)

(Abs)

0.0045

0.0000

0.0339

0.0294

0.0688

0.0643

0.1428

0.1383

0.3653

0.3609

0.3399

0.3354

0.3477

0.3432

0.6649

0.6605

1.0318

1.0274

1.1357

1.1312

0.2089

0.2045

0.3864

0.3819

Calibration Curve

Concentration (ppm) vs. Corrected-Absorbance (Abs)

1.6000

Corrected Absorbance (Abs)

1.4000

1.2000

y = 0.0071x

R² = 0.9593

1.0000

0.8000

0.6000

0.4000

0.2000

0.0000

0.00

50.00

100.00

150.00

Concentration (ppm)

200.00

Concentration (ppm)

Linear Calibration Curve

Concentration vs. Corrected-Absorbance (Abs)

Corrected Absorbance (Abs)

1.2000

1.0000

0.8000

0.6000

y = 0.00893x

R² = 0.99950

0.4000

0.2000

0.0000

0.00

20.00

40.00

60.00

80.00

Concentration (ppm)

100.00

120.00

nce (Abs)

250.00

120.00

140.00

Table 1

Dilution calculations for food dye solutions

Food Dye Concentration

Flask Volume

1

2

3

4

5

6

7

8

(ppm)

0.500

1.00

2.00

5.00

10.00

20.00

40.00

50.00

(mL)

50.00

50.00

50.00

50.00

50.00

25.00

25.00

25.00

9

Diluted unknown

100.0

10

Spiked unknown

100.0

Row

Table 2

Table 3

Volume of 100.0 ppm food dye stock solution used

50.00 ppm

40.00 ppm

Final Volume

14.50

24.50

(mL)

Volume of 100.0

ppm Food Dye

250.0

500.0

1.00

2.50

5.00

5.00

10.00

12.50

5.00 mL of

unknown +

0.00 mL of 100.0

ppm

5.00 mL of

unknown +

5.00 mL of 100.0

ppm

20.00 ppm

29.50

Initial Volume (mL)

2.00

14.50

24.50

Volume Added (mL)

12.50

10.00

5.00

Actual Food Dye

Concentration

(ppm)

50.00

40.00

20.00

BlankCorrected

Absorbance

Conc. Food Dye

(ppm)

0.004

0.022

0.023

0.022

0.020

0.022

0.023

0.023

0.022

0.101

0.556

0.581

0.556

0.505

0.556

0.581

0.581

0.556

Repeat analysis of 0.500 ppm food dye solution

Repeat

Measurement

1

2

3

4

5

6

7

8

Raw Absorbance

0.026

0.027

0.026

0.024

0.026

0.027

0.027

0.026

9

10

0.026

0.032

0.022

0.028

Average

0.027

0.023

0.573

x

0.002

0.052

Standard Deviation

s bl

Table 4

0.556

0.707

Data table for calibration curve, analysis of unknowns and spike recovery

Flask

1

2

3

4

5

5

5

5

5

Target Food Dye

Concentration

Raw

Absorbance

(ppm)

Exact Food

Dye

Concentration

(ppm)

Blank (DI water)

0.500

1.00

2.00

5.00

10.00

10.00

10.00

10.00

10.00

0.00

0.500

1.00

2.00

5.00

10.00

10.00

10.00

10.00

10.00

0.004

0.027

0.036

0.07

0.178

0.392

0.399

0.395

0.402

0.394

Average for 10.00

ppm food dye =

Standard deviation

for 10.00 ppm food

dye =

6

7

8

10.00

0.396

0.004

20.00

40.00

50.00

20.00

40.00

50.00

0.82

1.614

1.958

100.0 ppm

100.0

>2.5

Diluted Unknown

3.33

0.136

10

Spiked Unknown

Calibration Check[1]

5

10.00

8.41

0.337

10.00

0.395

9

Slope of graph

Diluted Unknown Conc

Spiked Unknown Conc

average [(avg. abs),(cal. Check)]

% difference

0.0396

3.33 ppm

8.41 ppm

0.392

0.357

5.00 ppm

102 %

Spiked Unknown Added

% spike recovery

Table 5

Summary Table of Quality Parameters

Quality

Parameter

LOD or c m

Absorbance Data (A)

0.500 ppm Food Dye

Solution

0.156

ppm

0.520

0.17

ppm

ppm

Using 10.00 ppm

Calibration Standard

in Table 4

Using the

Slope of the

Calibration

Curve

0.0392

0.0396

1.95E+04

1.97E+04

LOQ or c Q

MDL

Summary of

Absorptivity

Absorptivity (a )

(L/mg•cm)

Molar Absorptivity

(e) (L/mol•cm)

Literature Molar

Absorptivity (e)

(L mol–1∙cm–1)

%Difference for e

Analytical Sensitivity

Dynamic Range

Signal to Noise Ratio

2.41E+04

-19.2

2.41E+04

-18.4

10 1/ppm

49.5 ppm

97.2

µL

µL

ml

ml

ml

ml

ml

ml

ml

10.00 ppm

100 ppm

5.00 ppm

2.00 ppm

34.50

37.00

38.00

29.50

34.50

37.00

5.00

2.50

1.00

10.00

5.00

2.00

A

Conc »

m

Conc. Food

Dye (ppm)

0.101

0.556

0.581

0.556

0.505

0.556

0.581

0.581

0.556

BlankCorrected

Absorbance

0.004

0.022

0.023

0.022

0.02

0.022

0.023

0.023

0.022

Concentration vs. Bl

0.03

0.025

Absorbance

Dye

Concentration

0.02

0.015

0.01

0.005

0

0

0

0.556

0.707

0

0.022

0.028

Slope of Linear Calibration Curve

Slope of

Graph (m)

0.0396

Exact Food

BlankDye

Corrected

Concentration

Absorbance

(ppm)

BlankCorrected

Absorbance

Blank

2.5

0.00

0.500

1.00

2.00

5.00

10.00

10.00

10.00

10.00

10.00

0.000

0.023

0.032

0.066

0.174

0.388

0.395

0.391

0.398

0.390

0.392

20.00

0.816

0.004

40.00

1.610

0.816

1.610

1.954

50.00

100.00

1.954

>2.5

>2.5

0.132

0.333

0.391

Limit of Linearity

50.00

Absorbance

2

0.000

0.023

0.032

0.066

0.174

0.388

0.395

0.391

0.398

0.390

1.5

1

0.5

0

0

Molar mass

496.42 g/mol

Concentration vs. Blank-Corrected Absorbance

y = 0.0396x

R² = 1.0000

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Concentration (ppm)

Blank-Corrected Absorbance vs. Concentration

y = 0.0396x

R² = 0.9996

10

20

30

Concentration (ppm)

40

50

60

Table 1

Absorbance, Absorptivity (a), & Molar Absorptivity (ε) for food dye

repeat absorbance measurements and absorptivity calcul

value

corrected absorbance

0.428

0.428

0.428

(a) (ppm–1 cm–1)

0.0428

0.0428

0.0428

(ε) (L mol–1cm–1)

2.12E+04

2.12E+04

2.12E+04

(average ε) (L mol–1cm–1)

2.13E+04

(standard deviation of ε) (L mol–1cm–1)

(95% confidence interval of ε) (L

mol–1cm–1)

44.4

55.1

21246.78 21246.78 21246.78

tcalc

ttable

142.6900205

2.776

rements and absorptivity calculations

0.430

0.428

0.0430

0.0428

2.13E+04

2.12E+04

2.13E+04

44.4

55.1

21346.06 21246.78

1.18E+01

Blank

absorbance

Cuvette

length

Repeat conc.

Molar mass

(Allura Red)

Number of

observations

Theoretical

molar

absorptivity

0.001

1.00 cm

10.00 ppm

496.42 g/mol

5

2.41E+04

Vol of 100.0 ppm Food Dye Added

Unknown

Conc of

Blank

Sample

Food Dye corrected

vol

Final

Initial

Vol Added Added

Absorbance

10.00

0.00 ml Food Dye Added

0.00

0.547

10.00

27.03

26.00

1.03

2.06

0.631

10.00

42.95

40.99

1.96

3.92

0.721

10.00

31.97

28.98

2.99

5.98

0.810

10.00

35.99

31.97

4.02

8.04

0.893

10.00

40.99

35.99

5.00

10.00

0.978

14.57274827

0.941725

Conc of Stock Food Dye

Volume of

volumetric

flask

100.0 ppm

50.00 ml

Blank corrected Absorbance

1.200

1.000

0.800

y = 0.0433x + 0.547

R² = 0.9995

0.600

0.400

0.200

0.000

0.00

slope (m)

B/m

2.00

4.00

6.00

0.0433

12.6

Food Dye Conc

Spiked recovery

8.00

10.00

B

0.547

Dilution Factor 5.00

63.2

y = 0.0433x + 0.547

R² = 0.9995

10.00

12.00

Part B

Preparation of Zn Calibration Standards & Multivitamin Solution for Zn Analysis

Flask

BlankSolution

Exact Zn

corrected

(ppm Zn) conc (ppm) Absorbance % RSD Absorbance

1 Blank

0.00

0.0002

100

0.0000

2

0.5

0.500

0.1621

0.2

0.1619

3

1.0

1.00

0.3156

1.0

0.3154

4

1.5

1.50

0.4530

0.1

0.4528

5

2.0

2.00

0.5556

0.6

0.5554

diluted

6 vitamin

0.726

0.2234

0.5

0.2232

dil. Vit +

7 Zn spike

1.19

0.3654

0.6

0.3652

% spike recovery

Part C

92.4

Preparation of Zn/Multivitamin Solutions for Zn Analysis Using Standard Additio

Flask

Solution

dil. Vit. + 0

1 ppm Zn

Exact Zn

conc added

(ppm)

Absorbance % RSD

0.00

0.2532

0.5

dil. Vit. +

2 0.5 ppm Zn

0.50

0.3794

0.6

dil. Vit. +

3 1.0 ppm Zn

1.00

0.5143

0.1

dil. Vit. +

4 1.5 ppm Zn

1.50

0.6219

0.2

% spike recovery

101.7

BlankExact Zn

corrected

conc (ppm) Absorbance

0.000

0.0000

0.500

0.1619

1.000

0.3154

1.500

0.4528

2.000

0.5554

0.726

0.2232

1.19

0.3652

500 ppm

0.1 ml

Slope of

graph (m)

0.3073

dil. Conc.

dil. Factor

actual conc.

0.7270

100.0

72.70

Conc. Added

0.5000

0.4500

Blank-corrected Absorbance

Zn stock

solution

Zn stock

added

n Solution for Zn Analysis

0.4000

0.3500

0.3000

0.2500

0.2000

0.1500

0.1000

0.0500

0.5

0.0000

0.000

sis Using Standard Addition

0.7

0.6

dil. Vit. +

Zn spike

conc.

1.529 ppm

dil. Vit. Conc.

0.2482

1.020 ppm

0.5

Absorbance

Slope of

graph (m)

0.4

0.3

0.2

0.1

dil. Factor

100

dil. Factor

100.0

0

0.00

actual conc

152.9 ppm

actual conc

102.0 ppm

Conc vs. Blank-corrected Absorbance

0.5000

0.4500

y = 0.3073x

R² = 0.9994

0.4000

0.3500

0.3000

0.2500

0.2000

0.1500

0.1000

0.0500

0.0000

0.000

0.200

0.400

0.600

0.800

1.000

1.200

1.400

1.600

1.40

1.60

Concentration (ppm)

Conc Added vs. Absorbance

y = 0.2482x + 0.2561

R² = 0.9980

0.00

0.20

0.40

0.60

0.80

1.00

Concentration added (ppm)

1.20

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