A3 atomic absorption spectrophotometer is a laboratory analytical instrument based on atomic absorption spectroscopy (AAS), specifically designed to detect the content of trace metal elements in samples. Its core advantages lie in high sensitivity, high accuracy, and anti-interference ability, which are widely used in fields such as environmental monitoring, food safety, biomedicine, and metal materials.

1. Technical principle of A3 atomic absorption spectrophotometer: Atomic Absorption Spectroscopy (AAS)

(1) Basic principles

Atomization: The sample is converted into ground state atomic vapor by high temperature or chemical methods (such as flame atomization, graphite furnace atomization).

Absorption measurement: When light of a specific wavelength passes through the ground state atomic vapor, the atomic absorption is proportional to its concentration of characteristic spectral lines, resulting in a decrease in light intensity (following Lambert Beer's law).

Quantitative analysis: Determine the concentration of the target element in the sample by measuring absorbance and comparing it with the standard curve.

(2) Technical improvement of A3 model

Dual beam or multi-channel design: Real time correction of light source fluctuations to improve stability (such as alternating measurement of sample and reference beams).

High performance light source: using hollow cathode lamps (HCL) or electrode discharge lamps (EDL), emitting sharp line spectra that match the absorption lines of elements.

Spectral splitting system: High resolution grating splitting reduces background interference and improves detection limits (such as the ability to distinguish spectral lines of adjacent elements).

2. Core advantages of A3 atomic absorption spectrophotometer: high sensitivity and accuracy

(1) High sensitivity

Low detection limit: up to ppb level (such as flame method for detecting Cd, Pb and other elements, with a detection limit as low as 0.01ppm); The graphite furnace method can even reach the PPT level.

Example: In detecting trace heavy metals (such as As, Hg) in environmental water samples, A3 can accurately capture low concentration signals and avoid false negatives.

(2) High accuracy

Background correction technology:

Deuterium lamp background correction (DBC): eliminates molecular spectral interference in flames or graphite furnaces (such as avoiding phosphate interference when measuring Fe).

Zeeman effect background correction: By splitting spectral lines in a magnetic field, atomic absorption and background absorption can be distinguished, suitable for complex matrices such as soil digestion solutions.

Temperature control accuracy: During graphite furnace atomization, the temperature control accuracy reaches ± 1 ℃, ensuring consistent atomization efficiency and reducing repeatability errors.

(3) Anti-interference ability

Spectral line selectivity: By selecting specific absorption spectral lines (such as avoiding overlapping interfering elements), the influence of matrix effects is reduced.

Matrix improver: Adding lanthanum nitrate, ammonium salts, etc. to the sample to suppress the ionization of interfering elements or form stable compounds (such as adding NH? OH to eliminate Fe interference when measuring Pb).

Key components and functions of A3 atomic absorption spectrophotometer

(1) Atomizer

火焰原子化器：

Applicable elements: Na, K, Ca, Cu and other easily atomized elements.

Advantages: Simple operation, fast analysis speed (1-2 samples measured per second).

Disadvantages: High gas consumption and low sensitivity to non-volatile elements such as V and B.

Graphite Furnace Atomizer:

Applicable elements: non-volatile elements (such as Cr, Ni, Pb) and low-temperature elements (such as Zn, Cd).

Advantages: low detection limit, small injection volume (only a few microliters are required); Support direct solid injection (such as powder samples).

Disadvantage: Slow analysis speed (several minutes per sample).

(2) Optical system

Monochromator: High resolution grating (such as 1800 lines/mm) separates target spectral lines and eliminates interference from adjacent spectral lines.

Detector:

Photomultiplier tube (PMT): high sensitivity, suitable for low concentration element detection.

CCD array detector: capable of detecting multiple elements simultaneously, improving efficiency.

(3) Software and Automation

Automatic wavelength calibration: Intelligent recognition of element characteristic spectral lines, reducing manual operation errors.

Standard curve automatic generation: supports multi-point calibration (such as 0-5ppm gradient), fits linear correlation coefficient>0.999.

Data output: Directly display concentration values and be compatible with GLP/ISO standard data processing and report generation.