Application Submitted

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1 Proposal #6 Application Submitted To: Program: Title of Project: Suggested Timeline: Dr. Arlene Courtney Ch 462 Experimental Chemistry Analysis of Lead leached from Fiesta Ware by use of Atomic Absorption Spectroscopy. Three Hours Date Submitted: ABSTRACT: Lead is a heavy metal with numerous uses in industry while concurrently posing serious health risks at higher concentrations. Hence, methods to analyze lead in a variety of media are essential. Dinner ware glazes are a potential source of lead. To analyze lead leached from the wares, Atomic Absorption Spectroscopy (AAS) can be used. This is done using a Flame Absorption Spectrophotometer and creation of a calibration curve. The procedure can detect lead levels of up to 100 parts per billion (ppb), be completed in a three hour period and performed with instrumentation and reagents in the Western Oregon University Chemistry 462 lab. It is expected that the analysis will result in leached lead levels of between 10 parts per million (ppm) and 100 ppm.

2 INTRODUCTION Fiesta Ware is a line of dinner ware that became significantly popular in the mid 1930s throughout the United States. The dinner ware gained great popularity for not only its unique color variety but also as a result of the mass promotion done by the Homer Luaghlin Company that produced the line. One key part of this production was the color glazing. Orange and red glazes used at the time by most potteries contained traceable levels of Uranium oxide (13). Thus, the ware with these glazes commonly referred to as Red Fiesta was radioactive and concerns were that heavy metals from the decay of uranium, most notably lead, could leach out of the glaze during use of the dinner ware and cause harm. Lead is the heaviest common element with an atomic weight of g/mol (4). The heavy metal is the stable end product of Uranium-238 decay and is also found in many ores, namely Cerrosite, Galena and Anglesite (4). The metal has numerous uses spanning nearly all aspects of modern day life. It is a key component in batteries, electrical cable sheath, ammunition, paint, X-ray shielding, glass ware and production of numerous chemical compounds (7). However, the metal is also a cumulative environmental and body poison. The discovery of this danger has limited its use in many areas such as antiknock additives in gasoline and pottery glaze. Furthermore, effective methods to detect this potential poison have been developed. The Atomic Absorption Spectroscopy (AAS) (4) procedure prescribed in this proposal will prove to be an efficient method to determine lead levels leached from the Fiesta Ware pottery by vinegar after 24 hours. If this is so, the method will be able to detect lead levels of up to 100 parts per billion (ppb) (8). The procedure will also utilize instrumentation and reagents found in the University Chemistry (CH 462) lab.

3 Furthermore, the analysis will be able to be carried out in approximately three hours given that the four of the six investigators will have prior knowledge of the procedure and instrumentation. Hence, the procedure should prove to be a viable efficient way to test lead levels leached from Fiesta Ware pottery. In this proposal, methods for analyzing the lead content in aqueous solution are investigated. The most feasible explored is AAS and is hence extensively described. JUSTIFICATION Dizziness, irritability, abdominal pain, impotence, kidney damage, liver damage and death are a few of the effects of lead poisoning (1, 6). Thus, an efficient procedure to determine the lead content that may be present in everyday items such as pottery is vital to prevent unnecessary lead poisoning among the general public. AAS allows for a relatively quick analysis to be done on a particular aqueous sample. The procedure results in a limit of detection of approximately 100 ppb or 0.1mg/L for most elements (8). The procedure is relatively safe as long as sufficient scientific caution is exhibited, as is the case most chemical experiments. Furthermore, the instrumentation and reagents required for the AAS procedure are readily available in analytical labs such as the CH 462 lab. LITERATURE REVIEW All the literature reviewed indicated that lead is indeed of great use in industry; however its toxicity does require effective methods for its analysis to be monitored. The publications highlighted an array of methods that can be used to analyze lead levels in a variety of media. These included AAS, isotope dilution gas chromatography-mass

4 spectrometry, flow injection analysis (FIA), anodic stripping voltammetry, potentiometry, and laser atomic fluorescence (1). According to Ward and Fishman (4), selecting of analytical methods to analyze lead in a certain media requires a level of scientific judgment and a consideration of the budget allocated to the particular project. They suggest methods commonly used by the United States (U.S) Geological Survey. For lead in aqueous solutions, the two main methods utilized by the U.S Geological Survey are AAS and Atomic Emission Spectroscopy (AES). They go further to indicate the requirement for an acidic solution to be used if AAS is to be carried out. This acidic condition prevents lead absorption by glass instrumentation used during the procedure. In the work by Dr. Pete Poston (8) documenting a lab for lead analysis via AAS, the analysis technique is investigated further. The AAS method is well defined by the Environmental Protection Agency (EPA) in their EPA Method This document indicates that if the procedure is adequately followed a minimum detection limit of 0.1mg/L (100ppb) can be achieved as lead is analyzed. The method (8) also stipulates that a spectrophotometer with a lead hollow cathode lamp of wavelength 283.3nm is required for the analysis. Furthermore, as stated by Ward and Fishman (4), the samples should have a ph below two and addition of dilute nitric acid is suggested. Reviewing further literature by Dr. Poston and Brian M. Tissue (11), affirms that AAS will be the most effective method to undertake in determining the lead levels in the vinegar. All the instrumentation and reagents required will be readily available in the lab and the analysis will not exceed a three hour period. Furthermore, a limit of detection of

5 100 ppb will be attainable. The procedure will also be relatively safe with the key caution being measures taken to prevent a Flash back explosion by the Laminar flow burner. The literature by Yusuf and Ahmad (1) does provide an alternative method for the analysis via a flow cell Optosensor. However, the construction of the flow cell and the instrumentation required such as the fiber-optic spectrophotometer (Ocean Optic SD 100) would prove very challenging for the six investigators given their current expertise; the materials required would also not be readily available in the lab. Furthermore, the procedure does call for a 14 day drying period for one of the key components of the analysis; hence the procedure would also clearly not be feasible from a time perspective. MATERIALS AND METHODS The AAS analysis of the lead in the vinegar solution will require the Flame Absorption Spectrophotometer shown in figure 1. This is readily available in the lab. The instrument is composed of a hollow cathode lamp made of lead (8). This allows production of emission spectra that will only be absorbed by lead atoms aspirated in the flame. This absorption of energy by the aspirated lead atoms is the basis of the detection method. The amount of energy absorbed will indicate the concentration of lead present in the aspirated sample. Reagents required for the analysis will be a stock solution of lead (II) nitrate 0.003M (1000 ppm), a ready supply of freshly distilled water, and 500 ml of 1% Nitric acid. These reagents are all available in the lab and no expenditure will be required. Supplemental instrumentation required will be a10 ml measuring cylinder, a set of Eppendorf pipettes capable of dispensing up to 2500 µl, ten test tubes, twelve 10 ml beakers, and five 250 ml beakers. This supplemental instrumentation is also readily

6 available in the lab. Microsoft Excel (2000 or later) will also be required on a functioning computer for the data analysis. The Excel on the lab computers will be adequate. The analysis will be carried out by first adjusting the spectrophotometer for optimum performance. This will be followed by calibration of the instrument using standards created from the stock solution. Once calibrated, the lead leached into the vinegar will be analyzed. The limit of detection of the procedure and the lead content in the vinegar will be determined mathematically in Excel. The complete analysis will not exceed three hours. The detailed procedure to be followed will be: 1). Create standard lead solutions from the lead (II) nitrate stock solution 0.003M. 10 ml of each of the ten standard solutions will be prepared. The standards concentrations will be 2, 4, 8, 12, 20, 30, 50, 70, 80 and 100 ppm. This is done by use of the dilution equation and the Eppendorf pippetes. The dilute nitric acid (1%) is the solvent. For example, to create the 2 ppm standard, dilute ml of the stock solution with the solvent to get a 10 ml mixture. To adjust the spectrophotometer for optimum results, the following steps should be followed: 1). Ensure the spectrophotometer is turned on and make sure the Fuel Toggle Switch and the Oxidant Selector Valve are off. 2). Turn on the air supply valve and turn the Function Switch to the Lamp 1 (L1) position. 3). Turn the Function Switch to PMT volts adjusting the voltage to -350 V by using the Absorbance Zero dial. 4). Set the Wavelength dial to roughly 287 nm and rotate the dial upwards until the Energy meter is at maximum. 5). Turn on the acetylene fuel and ignite the burner with caution. 6). Ensure that the Horizontal Lamp and Vertical Lamp dials are adjusted to give the maximum deflection on the Energy meter. 7). Set the Function switch to an Absorbance Zero. Then press the Auto Zero switch. A 10 ml sample of the solvent (nitric acid) which will be the blank during the experiment can then be aspirated and the Zero button pressed thereafter. 8). Aspirate 10 ml the stock solution of lead (1000 ppm) and maximize the absorbance by adjusting the burner s vertical, horizontal and rotational knobs. Adjust the vertical position with care to avoid blocking of the hollow cathode lamp. The absorbance can be further maximized by adjusting the Fuel flow control valve and rotation of the Nebulizer and Oxidant fitting.

7 To create a calibration curve for the analysis, the following procedure will be followed: 1). The nitric acid (blank) will be aspirated and the absorbance zeroed. 2). 10 ml samples of the standards should be set in the 10 ml beakers in order of increasing concentration. Thus 2 ppm will be aspirated first. This nullifies any contamination. 3). The absorbance of each of the standards is noted after aspiration and the blank should be aspirated in between each standard. 4). The series should be repeated twice over with the three absorbance readings for each standard noted and the average calculated. 5). Then aspirate a 10 ml sample of lead in the vinegar and note the absorption. Repeat this twice, aspirating the blank and re-zeroing between each time. The greatest challenge expected during the experiment is the possibility of a Flashback explosion (9) when the flame is turned off. This can occur as the flame burns back to the waste (air) container and an explosion can result. To reduce the chances of this happening, the drain tubing will be looped and partially filled with water. A widemouthed waste tube will also be used. Other problems that could arise are the lamp temperature exceeding the flame temperature. This would lead to band broadening minimizing the efficiency of the analysis. However, the instrumentation available in the lab is manufactured to prevent this from happening. Once the experimental section is complete, final analysis via Excel can be done. The procedure to be followed will be: 1). When the excel program is open. Create headings for Concentration and Absorbance in A1 and B1 respectively. Input A2-A12 with the standard concentrations (including the 0.00 ppm for the blank) and a fill the column next to it (B) with the corresponding average absorbance readings. Include a 0.00 absorbance for the blank. 2). Create a line graph of absorbance vs. standard concentration. 3). Select the Data Analysis option in the tools menu and then select the Regression option. Select the absorbance readings for the Y Range and the concentrations for the X Range. 4). Note the intercept and slope(x Variable) in the output sheet. In a third column (C2- C12) enter the equation = (slope)*(a2 value) + (Intercept) entering the appropriate values in the parentheses. Copy (drag) this formula down to C12. This creates data fitted to a straight line using least squares. 5). Create a line graph of concentration vs. fitted data. This graph is the calibration curve and can be used to calculate the concentration of the lead in vinegar from its equation.

8 6). Using the Limit of Detection equation: L.O.D = [3(standard deviation of blank)]/ (slope). With the standard error of the y-intercept being the standard deviation of the blank. CONCLUSIONS It is expected that the procedure will be completed in the three hour period with the lead content in the vinegar analyzed successfully. A key assumption made in this procedure is that lead levels in the vinegar sample will be between 2 ppm and 100 ppm. If this is the case, the calibration curve will prove adequate in determining the lead content. However, in the case that the lead levels exceed or are below this range, the lead levels will be determined via extrapolation of the calibration curve or if time permits, creation of new standards with higher or lower concentrations whose absorbance readings will then be added to the calibration curve.

9 REFERENCES: [1] Yusof, Nor Azah; Ahmad, Musa. A flow cell optosensor for lead based on immobilized gallocynin in chitosan membrane. Talanta 2002, 58, [2] Hutter, Sarah. A new lead culprit. Working mother 1997, [3] Brown, D.W; Hem, J.D. Development of a Model to Predict the Adsorption of Lead from Solution of a Natural Streambed Sediment; United States Geological Survey Water- Supply No. 2187; U.S Government Printing Office: Washington, DC, 1984; 1-2, [4] Lovering, T.G. Lead in the Environment; United States Geological Survey Water- Supply No. 957; U.S Government Printing Office: Washington, DC, 1976; 1-4, [5] Nominations of the 108 th Congress, Second Session. Hearing before the Committee on Environment and Public Works United State Senate; U.S Government Printing Office: Washington, DC, 2005; , , [6] Lead and Lead Poisoning; Oregon Occupational Safety & Health Division; Department of Consumer and Business Services: Salem Central Office, OR, [7] Tilstone, William J.; Savage, Kathleen A.; Clark, Leigh A. Forensic Science: An Encyclopedia of History, Methods, and Techniques; ABC-CLIO, Inc: Santa Barbara, CA, 2006; 201. [8] Poston, P. Lab#6 Analysis of Lead by Atomic Absorption Spectroscopy. Presented at Chemistry 313 lab, Western Oregon University, Monmouth, OR, May [9] Poston, P. What is Atomic Spectroscopy? Sec Presented at Chemistry 313 lecture, Western Oregon University, Monmouth, OR, May [10] Atomic Absorption Spectroscopy, Introduction. http.// (accessed Jan 22, 2008). [11] Tissue, Brian M. Atomic-Absorption Spectroscopy (AA). http.//elchem.kaist.ac.kr/vt/chem-ed/spec/atomic/aa.htm (accessed Jan 22, 2008). [12] Atomic absorption spectroscopy. Wikipedia, (accessed Jan 22, 2008). [13] Fiesta (dinnerware). Wikipedia, (accessed Jan )

10 Figure 1