Atomic absorption spectroscopy (AAS) is used to analyze metal samples by determining the presence and concentration of metals in a liquid sample. Metals include Fe, Cu, Al, Pb, Ca, Zn, Cd and many more. It also measures the concentrations of metals in the samples. Typical concentrations range in the low mg/L range.
In their elemental form, metals will absorb ultraviolet light when they are excited by heat. Each metal has a characteristic wavelength that will be absorbed. The AAS instrument looks for a particular metal by focusing a beam of UV light at a specific wavelength through a flame and into a detector. The sample of interest is aspirated into the flame. If that metal is present in the sample, it will absorb some of the light, thus reducing its intensity. These instruments measure the change in intensity. A computer data system converts the change in intensity into an absorbance.
The following applications are typical uses for AAS analysis, along with industry examples where this type of testing would be performed:
Atomic absorption spectroscopy (AAS) is performed by focusing a beam of ultraviolet (UV) light of a known wavelength through a flame and into a detector. The liquid sample of interest is atomized into a gaseous state and aspirated into the flame (solid samples. In their elemental form, metals will absorb UV light when they are excited by heat. Each metal has a characteristic wavelength that will be absorbed, and the absorbance is proportional to the concentration of the analyte in the sample. The detector measures the change in intensity of the UV beam and a computer converts the change in intensity into a concentration for that element.
General Specifications |
Wavelength Range |
190 – 900 nm |
Wavelength Accuracy |
Better than 0.25 nm |
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Resolution |
Two spectral lines of Mn at 279.5 nm and 279.8 nm can be separated with the spectral bandwidth of 0.2nm, and valley-peak energy ratio less than 40% (30% for WFX-210) |
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Baseline Stability |
0.004 Abs / 30 min |
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Background Correction |
The D2 lamp background correction capability at 1 Abs is better than 30 times The S-H background correction capability at 1.8 Abs is better than 30 times |
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Light Source System |
Lamp Turret |
WFX-130 – 4-lamp turret, auto-alignment, automatic fine adjustment, manual wavelength selection, peak picking Other models – 6-lamp turret (2 high performance HCLs can be mounted to increase sensitivity of flame analysis), auto-alignment, automatic fine adjustment, fully automated scan and peak-picking |
Lamp Current Adjustment |
Automatic adjustment and display Wide pulse current: 0 – 25 mA Narrow pulse current: 0 – 10 mA |
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Lamp Power Supply Mode |
Powered by two pulses simultaneously |
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Optical System |
Monochromator |
Single beam, Czerny-Turner design grating monochromator |
Grating |
1800 l/mm |
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Focal Length |
277 mm |
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Blazed Wavelength |
250 nm |
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Spectral Bandwidth |
0.1 nm, 0.2 nm, 0.4 nm, 1.2 nm, automatic switchover |
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Atomizer |
Flame/Graphite Furnace |
Automatic ignition Flame & graphite furnace atomizer automatic changeover, automatic graphite furnace position optimization, automatic flame height setting and horizontal position optimization Alarm and automatic protection functions for gas leak, abnormal flow, insufficient air pressure, abnormal flame extinction |
Flame Analysis |
Burner |
10 cm single slot all-titanium burner |
Spray Chamber |
All-plastic spray chamber |
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Nebulizer |
High efficiency glass nebulizer with metal sleeve |
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Characteristic Concentration and Detection Limit |
Air-C2H2 Flame |
Cu calibration: Detection limit ≤ 0.006 mg/L |
Oxygen-Enriched Air-C2H2 Flame |
Ba calibration: Al calibration: Characteristic concentration ≤ 0.4 mg/L |
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Graphite Furnace Analysis |
Temperature Range |
Up to 3000ºC |
Light-Controlled Temperature Range |
1500ºC - 3000ºC, temperature auto-correction |
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Temperature Control Accuracy |
≤ 1% |
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Heating Rate |
2000ºC/s |
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Characteristic Mass |
Cd ≤ 0.5 (10-12g), Cu ≤ 5 (10-12g), Mo ≤ 1 (10-11g) |
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Precision |
Cd ≤ 3%, Cu ≤ 3%, Mo ≤ 4% |
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Safety Protection |
Protections for over-heating, over-current, insufficient cooling water, and argon pressure monitoring |
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Graphite Furnace Autosampler |
Sample Tray Capacity |
55 sample cups and 5 cups for matrix modifier |
Sample Cup Material |
Polypropylene |
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Standard Cup Volume |
3 mL for sample, 20 mL for matrix modifier |
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Number of Repeatable Measurements |
Up to 99 times |
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Sampling System |
100 µL and 5 mL injectors, large flow sampling nozzle rinsing |
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Sampling Precision and Repeatability |
Precision: 1% Repeatability: 0.3% for minimum sampling volume |
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Auto-Correction |
Sampling nozzle auto-correction, sample cup height auto correction |
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Detection and Data Processing System |
Detector |
Photomultiplier with high sensitivity and wide spectral range |
Software |
Windows OS |
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Analytical Method |
Working curve method (1st order and 2nd order fitting) with automatic sensitivity correction; standard addition method |
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Concentration |
Auto-calculation of concentration and content |
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Repeatable Measurement |
Repeated measurement of up to 99 times, automatic calculation of mean value, standard deviation, and relative standard deviation |
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Multi-Task Functions |
Sequential measurement for multi-element determination within the sample (maximum 6 elements, depending on model) |
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Condition Reading |
With model function |
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Result Printing |
Measurement data and final analytical report printout, editable with Excel |
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