What does AA mean in CHEMISTRY

Atomic Absorption (AA) is a spectroscopic technique used for the quantitative analysis of elements in liquid or gas samples. It uses light absorption to measure the concentration of specific atomic species in a solution. By exciting atoms within the sample with a source of radiation, those atoms can absorb some of that energy and subsequently emit light at an amplified wavelength.

In Atomic Absorption spectroscopy, a hollow cathode lamp or an electrodeless discharge lamp produces a monochromatic light source, most commonly UV or visible light. A sample is aspirated into the flame and is atomized into free atoms which then absorb photons from the light source. The concentration of an element in the sample can be calculated as a function of the amount of transmitted light after passing through that sample compared to that when there was no sample inserted in between.

Samples for atomic absorption analysis can include liquids, gases, tissue homogenates, soils, sediments and water. Each sample must be prepared according to its type before being introduced into the instrument for analysis; often times these preparations include steps like digestion, distillation or extraction.

Some common applications for Atomic Absorption include measuring trace elements in biological fluids such as urine or blood serum; monitoring pollutants in air or water; analyzing metals in metal alloys; tracking levels of lead paint on furniture and toys; analyzing food contaminants; determining nutrient content in soil samples; and measuring elements deposited onto surfaces through corrosion processes.

One main advantage associated with Atomic Absorption compared to other analytical techniques is its high sensitivity and selectivity capabilities – AA instruments are able to detect concentrations down at parts per billion levels (ppb) with low background interference from other elements present in the same sample matrix. Additionally, since most AA methods require no chemical pretreatment prior to analysis it eliminates any potential sources of errors due to incorrect pretreatments.

One potential drawback associated with using atomic absorption relates to its limited dynamic linear range – due to it being based on Beer’s Law where absorbance is proportional to concentration, once concentrations reach above higher levels they exceed detection limits which leads to non-linear response curves and saturation issues that may occur if proper dilutions aren’t made beforehand.

Common detector choices for AA instruments include both single element detectors such as nitrogen-phosphorus detectors (NPDs) as well as multielement detectors like flame photometers (FPs) or inductively coupled plasma mass spectrometers (ICP-MS). Each one offers valid options depending on what type of application you’re testing for while all generally provide improved sensitivity versus manual titration methods.

Yes – interferents will interfere with correct results obtained from atomcic abosrptions because they tend mask true analyte absorptivity signals by shifting them either towards longer wavelengths outside detectable ranges or just overlapping them altogether thus masking their unique effects.