Popular guidelines

How do you prepare samples for atomic absorption spectroscopy?

How do you prepare samples for atomic absorption spectroscopy?

A typical sample preparation procedure for solid and viscous liquid samples involves digestion with a concentrated acid; for example, HNO3, HCl, or H2SO4. After dilution of the digested solutions, samples can be directly injected into flame AAS as well as graphite furnace AAS.

How accurate is atomic absorption spectroscopy?

Accuracy. AAS is a great method of producing accurate results, normally with a rate of 0.5-5%, or an even better rate if appropriate standards are used. Sensitivity. An incredibly sensitive method of detection, AAS can actually measure all the way down to parts per billion of a gram in a substance.

What are the applications of atomic absorption spectroscopy?

Atomic absorption spectroscopy has been utilized in the study of forensic sciences for many years. Using this technology, forensic scientists can perform in-depth analysis of blood samples, brain and muscle tissue, and gunshot powder residue.

What is flame atomic absorption spectroscopy?

Flame atomic absorption is a very common technique for detecting metals and metalloids in environmental samples. It is very reliable and simple to use. With the Flame AA, the sample atomization occurs when a liquid sample is drawn into a flame.

What is the basic principle of atomic absorption spectroscopy?

Atomic absorption spectroscopy (AAS) is based upon the principle that free atoms in the ground state can absorb light of a certain wavelength. Absorption for each element is specific, no other elements absorb this wavelength.

What is the principle of AAS?

Principle of AAS AAS quantitatively measures the concentrations of elements present in a liquid sample. It utilises the principle that elements in the gas phase absorb light at very specific wavelengths which gives the technique excellent specificity and detection limits.

Why acetylene gas is used in AAS?

In FAAS, the most common AA technique, Acetylene is commonly used as a fuel gas and requires low levels of Phosphine and Hydrogen Sulphide to give a cleaner flame and less interference to ensure optimum analytical accuracy.

What is the purpose of the flame in AAS?

The flame is lined up in a beam of light of the appropriate wavelength. The flame (thermal energy) causes the atom to undergo a transition from the ground state to the first excited state. When the atoms make their transition, they absorb some of the light from the beam.

What is the hottest burning gas?

Because of its high endothermic heat of formation, it can explode to carbon powder and nitrogen gas, and it burns in oxygen with a bright blue-white flame at a temperature of 5260 K (4990 °C, 9010 °F), the hottest flame in oxygen; burnt in ozone at high pressure the flame temperature exceeds 6000 K.

What is the hollow cathode lamp used in AAS made of?

Hollow cathode lamps A HCL is composed of a silica envelope that contains 1–5 Torr of argon or neon and two metal electrodes. HCLs are almost ideal line sources for AAS because of their high stability and narrow linewidth (0.002 nm), but their relatively low intensity is a disadvantage for AFS.

What is a releasing agent in AAS?

a) A releasing agent is a substance that reacts preferentially with a chemical interference, thus preventing its interaction with the analyte.

What is the detection limit of AAS?

The limit of detection for different instrument varies. Some has it as 0.001 mg/L, others as 0.01 mg/L.

What is interference in AAS?

An interference is a phenomenon that affects the measurement or the population of ground state atoms of an analyte element. Related links: Flame Atomic Absorption. Cold vapor Hg/As. Interferences in AA analysis.