ATOMIC ABSORPTION SPECTROSCOPY

Atomic Absorption Spectroscopy (AAS)

It is an analytical technique used to determine the concentration of specific metal elements in a sample.

1. Light

2. Free atoms

3. Gaseous State

Atomic Absorption Spectroscopy (AAS) works by measuring the amount of (1) ____ absorbed by (2) ____ in (3) ____

Specific wavelength

In (AAS), Each element absorbs light at a _____ wavelength, allowing accurate identification and quantification.

Beer-Lambert Law

What law states that “Absorbance is proportional to concentration” in the context of AAS

1. characteristic

2. Beer-Lambert Law

3. atomized

4. free atoms

5. amount absorbed

• Atoms absorb light at (1) ____ wavelengths

• Absorbance is proportional to concentration ((2) ____)

• Sample is (3) ____ into (4) ____

• Decrease in light intensity = (5) ____

1802

What year did William Hyde Wollaston observed dark lines in the solar spectrum, later mapped in detail by Joseph Von Fraunhofer (Faunhofer), which were absorption lines from elements in the sun’s atmosphere?

William Hyde Wollaston

Who observed dark lines in the solar spectrum in 1802?

Joseph Von Fraunhofer

Who mapped in the detail of the observed dark lines in the solar spectrum?

Fraunhofer lines

What do you call the mapped in detail by Joseph Von Fraunhofer?

Absorption lines

The observed dark lines where classified as what type of lines from elements in the sun’s atmosphere?

1955

What year did Australian physicist Alan Walsh published his seminal paper “The Application of Atomic Absorption Spectra to Chemical Analysis”?

Alan Walsh

An Australian physicist who published his seminal paper “The Application of Atomic Absorption Spectra to Chemical Analysis”

Hollow Cathode Lamp

Alan Walsh solved key challenges - creating a sharp line source called what?

• Creating a sharp line source (Hollow Cathode Lamp)

• Separating the absorption signal from emitted light

Key challenges Alan Walsh solved?

• Flame AAS

• Graphite Furnace AAS

• Cold Vapor AAS

• Hydride Generation AAS

Enumerate the types of AAS

• Flame atomizer

• Graphite furnace

Enumerate the 2 types of Flame Atomizers

1980s

What year was the introduction of computer-controlled instruments, automatic samplers, background correction techniques (Zeeman, Smith-hieftje), and later, compact, low maintenance designs.

Graphite Furnace Atomizer

What kind of Atomizer that vastly improves sensitivity and allowing solid and micro-samples to be analyzed

Perkin-Elmer and others.

Which companies released the first commercial AAS instruments in the 1960s?

• Hollow Cathode Lamp (HCL)

• Nebulizer-burner system

What was the standard used in the 1960s as commercial AAS instruments?

Boris L'vov

Who introduced the graphite furnace atomizer for electrothermal atomization in the 1960s-70s?

It improved sensitivity and allowed for the analysis of solid and micro-samples.

How did the introduction of the graphite furnace improve AAS analysis?

Electrothermal atomization

Other term for Graphite Furnace Atomizer

• Light source

• atomizer

• monochromator

• detector

• readout system.

What are the five main components of an AAS instrument?

It emits element-specific wavelengths to ensure selectivity and accuracy.

What is the function of the Hollow Cathode Lamp (HCL) in AAS?

Atomizer

It converts the sample into free atoms.

Monochromator

It isolates the specific wavelength of interest and removes unwanted radiation.

Photomultiplier Tube (PMT)

Which component in AAS acts as the detector to measure absorbed light?

Parts per million PPM or lams mo na PPB

In what units does the readout system typically display the concentration?

Air-acetylene

Which gas combination is commonly used for routine analysis in a flame atomizer?

FAAS is fast and less sensitive, GFAAS is highly sensitive

How does Flame AAS (FAAS) compare to Graphite Furnace AAS (GFAAS) regarding speed and sensitivity?

Graphite Furnace AAS (GFAAS)

Which AAS atomization technique is preferred for trace-level detection due to its higher sensitivity?

Cold Vapor AAS

What specialized AAS technique is used specifically for the analysis of mercury?

• Arsenic (As)

• Selenium (Se)

Hydride Generation AAS is used to analyze elements like _____.

• Water

• soil

• air emissions

In environmental monitoring, AAS is used to detect toxic heavy metals in which three media?

• Lead (Pb)

• Cadmium (Cd)

• Mercury (Hg)

• Arsenic (As).

Name four toxic heavy metals commonly monitored in the environment using AAS.

It analyzes ores and geological samples for precious and base metals.

How is AAS applied in the field of mining and geology?

• Gold (Au)

• Silver (Ag)

• Platinum (Pt).

What are three examples of precious metals analyzed in mining using AAS?

• Iron (Fe)

• Zinc (Zn)

• Calcium (Ca)

In the food industry, AAS is used to measure nutrient minerals such as _____.

They can poison catalysts or cause engine wear.

In petrochemicals, why is it critical to detect trace metals like Vanadium (V) and Nickel (Ni) in crude oil?

ICH Guideline Q3D

Which ICH guideline mandates elemental impurity testing in drug substances?

• Palladium (Pd)

• Platinum (Pt)

• Ruthenium (Ru)

AAS is used in pharmaceuticals to detect residual catalysts such as _____.

• Water

• solvents

• inactive ingredients (excipients).

In pharmaceutical quality control, which materials are tested to ensure they meet purity specifications for trace metals?

They can be introduced from manufacturing equipment.

How can metals unintentionally enter Active Pharmaceutical Ingredients (APIs)?

Lithium (Li)

Which specific metal might be intentionally added to certain drug formulations and quantified via AAS?

• Selenium (Se)

• Copper (Cu)

• Zinc (Zn)

In nutritional supplements, AAS is used to determine levels of essential elements like Chromium (Cr) and _____.

To detect leachable metal contaminants.

Why are pharmaceutical packaging materials like glass vials and rubber stoppers tested with AAS?

aluminum

AAS is used to test _____ seals in pharmaceutical packaging for contaminants.

Measurement of light absorbed at element-specific characteristic wavelengths.

What is the core principle used for identification in AAS?

emitted light

The 1955 breakthrough by Alan Walsh addressed the challenge of separating the absorption signal from _____.

• Air-acetylene

• Nitrous oxide-acetylene.

What are the two most common types of flame atomizers used in AAS?

Nickel (Ni)

In manufacturing, AAS is used to analyze base metals such as Copper (Cu), Zinc (Zn), and _____.

sensitivity

The ability of AAS to detect metals at extremely low concentrations is known as its _____.

Readout system

Which component is responsible for displaying the final concentration of the analyte?

EPA or WHO

AAS is critical for regulatory compliance with standards set by organizations like the _____.

Joseph von Fraunhofer

Who mapped the solar absorption lines in detail, giving them their common name?

"The Application of Atomic Absorption Spectra to Chemical Analysis."

What was the title of Alan Walsh's seminal 1955 paper?

• Environmental monitoring

• Mining and Geology

• Food and agriculture

• Petrochemicals

• Manufacturing

Enumerate the 5 Practical and Industrial Use of AAS

• Elemental impurity testing (ICH Q3D

• Quality control of raw materials

• Analysis of active pharmaceutical ingredients

• Nutritional supplements

• Packaging materials

Enumerate the 5 Pharmaceutical Relevance