AU Biomaterials Design Lab:Equipment/Shimadzu AA-6200
- Shimadzu AA-6200 double-beam atomic absorption spectrophotometer.
- It can detect the concentration of Au and Cu even at very low concentrations (ppm).
- The limit of detection for Cu absorption is 0.003 ppm.
- The limit of detection for Au absorption is theoretically 0.01 ppm, but in actuality is around 2-4 ppm.
Purpose of Use
- Atomic absorption spectroscopy is used to detect trace amounts of specific elements in solution to a high degree of precision. The sample passes through an acetylene-air flame, upon which it is atomized. This collection of atoms contains mostly atoms in the ground state and very few that have been excited to a higher energy state by the flame. An element-specific lamp that produces light at an extremely narrow wavelength shines upon the collection of atoms in the ground state and the absorbance is measured. The concentration of the sample is then calculated using Beer's law from a calibration curve of standard solutions of known concentration.
- Analysis of samples is relatively fast, compared to UV-vis spectroscopy. The path length in an AAS is also comparatively long (between 10 and 15 cm), which maximizes the accuracy of detection of trace amounts of analyte.
- However, relatively large sample amounts (around 1 to 2 mL) are required for analysis.
- American University
- Beeghly, Room 203
- 4400 Massachusetts Ave NW
- Washington, DC 20016
- Note that access to this room is restricted. Please ask Dr. Miller, Dr. Fox, or Dr. Hartings for access.
- Operation of the Shimadzu AA-6200
- Turn on the instrument and open the WizAArd program.
- Click Connect, then Next.
- Select the element, either Au or Cu, to be measured.
- Click Warmup Lamp, then Next.
- Adjust the lamp to the proper position by rotating it on the right side of the instrument. Click Next.
- Select the calibration method, enter the number of standards to be measured, and their concentrations. Click Next.
- Enter the number of samples to be measured and their identifications. Click Next.
- Ignite the flame by simultaneously pushing and holding the back and white buttons. Once the flame has ignited, release the buttons.
- Place the suction tube in deionized water, then click Blank to blank the instrument.
- Autozero by placing the suction tube in a solution of your choice, then clicking Autozero.
- Place the suction tube in deionized water between measurement of solutions.
- Place the suction tube in the first standard solution and click Start.
- Repeat the last two steps for all of the standard solutions, then continue on to the sample solutions.
- Extinguish the flame by pushing the red (extinguish) button.
- Click File -> Export Data to save the data as a text file.
- The following protocols utilize the AAS:
- Operate the AAS in a properly vented fume hood.
- Do not look directly at the flame and never leave the flame burning while unattended.
- Do not touch the casing near the flame, as it will become extremely hot when the flame is ignited.
- Be careful when using flammable solvents near the flame.
- Never prepare or store flammable solvents near the flame or any other ignition source.
- Physical: W690 x D425 x H370 mm, 38 kg
- Optics: Double beam, chopper mirror
- Monochromator: Czerny-Turner monochromator, holographic grating (1600 lines/mm)
- Wavelength range: 190-900 nm, automated wavelength selection
- Slit width: 0.2 nm or 0.7 nm, manual selection
- Lamp turret: 2 lamps, simultaneously lit, manual selection
- Lamp mode: Emission, non-BGC, BGC-D2
- Frequency: 100 Hz
- Nebulizer: Nebulizer integrated impact bead and jacket tip, Pt/Ir capillary
- Chamber: Polypropylene
- Burner: Fixed position and height, 10 cm titanium slot burner, manual selection between air/C2H2 and N2O/C2H2
- Gas control: Manual selection of flow rate, automatic air/N2O switching system
- Safety: Gas pressure monitoring, automatic flame monitoring, safety interlock for misuse of burner, automatic flame extinguish upon power failure
- Ignition: Manual selection
- Software: Based on Microsoft Windows, WizAArd
- Power requirements: AC220 V, 230 V, 50/60 Hz, 300 VA, requires transformer for AC115 V
- Ambient temperature range: 10~35°C
- Ambient humidity range: 45~80%, but less than 70% if temperature is above 30°C
- Repeatability: Under optimal conditions, RSD 0.5-1.5%
- Accuracy: Affected by sample matrix and method of calibration
Calibration Curve of Au Standards
- The AAS was calibrated with solutions of HAuCl4 in 1 N HCl at the following concentrations: 5 ppm, 8 ppm, 10 ppm, 15 ppm, 20 ppm, 25 ppm, 30 ppm, and 40 ppm.
Calibration Curve of Cu Standards
- The AAS was calibrated with solutions of CuSO4 in HPLC grade H2O.