Name: choosing light sources for aas measurements
Uploaded: 2024-12-05T18:32:14.000Z
Duration: 1 min 13 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Earth and Space Science

Space Systems

3.3.9-12.B

atomic-absorption-spectroscopy-radiation-and-light-sources

Atomic Absorption Spectroscopy: Radiation and Light Sources

AAS'nin Beer-Lambert yasasına uyması için, radyasyon kaynağının analit atomunun emdiğinden daha dar bir dalga boyu aralığı yayması gerekir.
İki yaygın dar aralıklı 'hat' kaynağı, içi boş katotlu lambalar veya HCL'ler ve elektrotsuz deşarjlı lambalar veya EDL'lerdir.
Bir HCL, analiz edilen elemanla kaplanmış silindirik içi boş bir katoda ve tümü düşük basınçta inert bir gazla doldurulmuş bir cam tüp içine alınmış bir tungsten veya zirkonyum anoda sahiptir.
Elektrotlar boyunca bir voltaj uygulamak, katot kaplamasını enerjik bir şekilde bombardıman eden, bazı atomları nakavt eden veya 'püskürten' inert gaz atomlarını iyonize eder.
Daha fazla çarpışma, karakteristik dalga boyunda radyasyon yayarak geri dönen bazı püskürtülmüş atomları heyecanlandırır.
Bazı elementler daha yoğun ve hassas EDL hat kaynağına ihtiyaç duyar - inert bir gaz ve analit elementi veya tuzu ile doldurulmuş sızdırmaz bir kuvars tüp.
Tüpün içindeki yoğun bir radyo frekansı veya mikrodalga radyasyonu alanı, atomları buharlaştırır ve onları heyecanlandırarak karakteristik spektrumlarının yayılmasına neden olur.

atomik absorpsiyon spektroskopisi

Atomik Absorpsiyon Spektroskopisi (AAS), Beer-Lambert yasasına dayanır; bu yasa, radyasyon kaynağının, analiz edilen atomun absorbsiyon özellikleriyle örtüşen dar bir dalga boyu aralığı yaymasını gerektirir. AAS'te uygun bir radyasyon kaynağının seçilmesindeki temel kriter, analitin doğru bir şekilde tespit edilmesini sağlayacak belirli dalga boylarında hassas ve yoğun bir emisyon sağlamaktır.

AAS'de kullanılan iki yaygın dar aralıklı "çizgi" kaynağı, analiz edilen element ve gerekli yoğunluğa bağlı olarak seçilen içi boş katot lambaları (HCL) ve elektrotsuz deşarj lambaları (EDL)dır.

İçi Boş Katot Lambaları (HCL'ler): HCL'ler, orta derecede yoğunlukla tespit edilebilen elementler için yaygın olarak kullanılır. Lamba, analiz edilen elementle kaplanmış silindirik bir boşluk katot, tungsten ya da zirkonyum anot içerir. Bunlar, düşük basınçta bir inert gazla dolu cam bir tüp içinde yer alır. Elektrotlar arasına voltaj uygulandığında, inert gaz atomları iyonize olur ve katoda çarpar. Bu çarpışma, analiz edilen atomların yerinden sıçramasına ve atomların salınmasına neden olur. Bu, elemente özgü radyasyonun yayılmasını sağlar. HCL'ler, güvenilirlikleri ve özgüllükleri nedeniyle birçok rutin AAS ölçümü için idealdir.

Elektrotsuz Deşarj Lambaları (EDL'ler): EDL'ler, daha hassas veya yoğun radyasyon gerektiren elementler için kullanılır. Bu lambalar, inert gaz ve analiz edilen element veya onun tuzunu içeren kapalı bir kuvars tüpüne sahiptir. Güçlü bir radyo frekansı veya mikrodalga alanı uygulandığında, analiz edilen madde buharlaşır ve uyarılır, böylece karakteristik spektrumunu yayar. EDL'ler, HCL'lere kıyasla daha yoğun emisyonlar sağlar ve bu nedenle daha yüksek hassasiyet ve doğruluk gerektiren elementler için uygundur.

Hem HCL'ler hem de EDL'ler, AAS analizinin özel gereksinimlerine göre seçilir ve yayılan radyasyonun, doğru ölçümler için analiz edilen maddenin absorbsiyon özellikleriyle örtüşmesini sağlar.

Atomik Absorpsiyon Spektroskopisi

Atomik absorpsiyon spektroskopisi (AAS), radyasyon kaynağının eşleşmesi için dar bir dalga boyu aralığı yaymasını gerektiren Beer-Lambert yasasına dayanır ...

Education

JoVE Core

Analytical Chemistry

Analitik Kimya

Unit 1

Ünite 1

Atomic Spectroscopy

Atomik Spektroskopi

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

choosing light sources for aas measurements

Atomic absorption spectroscopy (AAS) uses a light source that emits a very narrow range of wavelengths. This is needed because the source must match the absorption behavior of the analyte atom. The choice of source also depends on giving a precise, intense emission at the right wavelength for accurate detection.

Two common line sources in AAS are hollow-cathode lamps (HCLs) and electrodeless-discharge lamps (EDLs). These lamps are selected based on the element being analyzed and the level of intensity needed. Each one helps the instrument measure the analyte by sending out element-specific radiation.

Hollow-cathode lamps are widely used when moderate intensity is enough. An HCL has a cylindrical hollow cathode coated with the analyte element and a tungsten or zirconium anode. The parts sit inside a glass tube filled with an inert gas at low pressure. When voltage is applied, the gas atoms become ionized and strike the cathode. This causes sputtering, which knocks analyte atoms off the cathode and makes them emit radiation specific to that element.

Electrodeless-discharge lamps are used when more precise or more intense radiation is needed. An EDL contains a sealed quartz tube with an inert gas and the analyte element or its salt. A strong radio-frequency or microwave field vaporizes and excites the analyte. The excited atoms then emit their characteristic spectrum. EDLs give stronger emission than HCLs, so they are useful when higher sensitivity and precision are needed. Both lamp types are chosen to make sure the emitted radiation matches the analyte absorption in AAS measurements.

Choosing Light Sources for AAS Measurements

choosing-light-sources-for-aas-measurements

atomic spectroscopy: absorption, emission, and fluorescence

atomic-spectroscopy-absorption-emission-and-fluorescence

Element Analysis with Atomic Light Spectra

Atomic spectroscopy is used to identify and measure elements by their light signals. It supports both qualitative analysis, which tells what is present, and quantitative analysis, which tells how much is present. The optical methods in this group are atomic absorption spectroscopy, atomic emission spectroscopy, and atomic fluorescence spectroscopy. These methods begin with atomization. In this step, a solid, liquid, or solution sample is changed into gas-phase atoms and ions. Once the sample...

atomic spectroscopy: effects of temperature

atomic-spectroscopy-effects-of-temperature

How Heat Changes Atomic Spectra

Heat changes atomic spectra by affecting atomization, excitation, ionization, and line shape. In atomic spectroscopy, atomization means converting a sample into gas-phase atoms and ions. The flame temperature needed for this step changes how efficiently the method works and shifts the balance between excited and ground-state atoms. At thermal equilibrium, the relative numbers of excited and ground-state atoms can be estimated with the Maxwell-Boltzmann distribution. A small temperature rise...

atomic absorption spectroscopy: overview

Atomic Absorption Spectroscopy for Trace Metals

Atomic absorption spectroscopy (AAS) measures trace metals by tracking how atoms absorb electromagnetic radiation (EMR). The absorbed light makes atoms move to a higher-energy orbit. In AAS, the key step is atomization, which converts the sample into gas-phase atoms. A flame or a furnace is typically used for this step. Inside the flame, some atoms become thermally excited. Most stay in the ground state, which is the lowest-energy state. These ground-state gas-phase atoms absorb EMR only when...

atomic absorption spectroscopy: instrumentation

atomic-absorption-spectroscopy-instrumentation

Atomic Absorption Spectroscopy: Key Parts

Atomic absorption spectrophotometry uses a set of key parts to measure light absorbed by atoms. The main components are a radiation source, an atomizer, a monochromator, and a detector. Each part has a specific job in the instrument. The radiation source is usually a hollow-cathode lamp, or HCL, or an electrodeless-discharge lamp, or EDL. Both produce a narrow emission line at the needed wavelength. Some instruments instead use continuum sources with high-resolution monochromators to narrow...

atomic absorption spectroscopy: radiation and light sources

Atomic absorption spectroscopy (AAS) uses a light source that emits a very narrow range of wavelengths. This is needed because the source must match the absorption behavior of the analyte atom. The choice of source also depends on giving a precise, intense emission at the right wavelength for accurate detection. Two common line sources in AAS are hollow-cathode lamps (HCLs) and electrodeless-discharge lamps (EDLs). These lamps are selected based on the element being analyzed and the level of...

atomic absorption spectroscopy: atomization methods

atomic-absorption-spectroscopy-atomization-methods

Atomic Absorption Spectroscopy: Sample Atomization

Atomic absorption spectroscopy uses sample atomization to turn a liquid specimen into free atoms for analysis. The two main approaches are flame atomization and electrothermal atomization. Both methods prepare the sample so its atoms can be measured by the instrument. Flame atomization uses a nebulizer and spray chamber to mix the sample with a fuel-oxidant mixture. This creates a fine aerosol mist that enters the burner. The fuel and oxidant are usually close to a stoichiometric ratio, but a...

atomic absorption spectroscopy: interference

atomic-absorption-spectroscopy-interference

Correcting Errors in Atomic Absorption Spectroscopy

Atomic absorption spectroscopy interference can create systematic error by making the analytical signal or the background look stronger or weaker than it should be. In atomic absorption measurements, these errors are usually grouped as spectral interference, chemical interference, and physical interference. Spectral interference happens when signals from other elements or molecules overlap with the analyte signal, the substance being measured. This overlap can falsely raise or hide the analyte...

atomic absorption spectroscopy: lab

AAS Sample Prep and Calibration

Atomic absorption spectroscopy (AAS) depends on careful sample preparation and calibration. Samples must be turned into clear solutions before measurement. That often means extra treatment to dissolve materials such as soils, animal tissues, and minerals. Common sample prep methods include hot mineral acids, wet ashing, combustion in closed containers, high-temperature ashing, and fusion with reagents. These steps help make the sample suitable for AAS analysis. Solutions that contain organic...

atomic emission spectroscopy: overview

Atomic Emission Spectroscopy for Element Analysis

Atomic emission spectroscopy is used to identify the elements in a sample by measuring the light they emit. Atoms are first excited to higher energy levels by thermal energy from hot sources such as plasma, arcs, or sparks. When they fall back to lower energy levels, they give off light at specific wavelengths. Each element produces its own set of lines, so the emission spectrum can show both what is present and how much is there. AES instruments are similar to atomic absorption spectrometers,...

atomic emission spectroscopy: instrumentation

atomic-emission-spectroscopy-instrumentation

AES Sample Handling and Detection

Atomic emission spectrometry (AES) uses sample handling, atomization, and detection parts to measure emitted light from atoms and ions. The sample must first be changed into a gas-phase form so it can produce a measurable signal. AES uses two main atomizer types. Continuous atomizers, such as flames and plasmas, feed the sample in a steady stream. Discrete atomizers add one sample at a time with syringes or autosamplers. The electrothermal atomizer is the most common discrete type. Many...

atomic emission spectroscopy: interference

atomic-emission-spectroscopy-interference

Reducing Interference in AES Signals

Atomic emission spectroscopy (AES) can produce interfering signals when atoms and molecules in a flame or plasma emit overlapping light. High-temperature atomizers excite many species at once, including oxides, hydroxides, and flame combustion products. These extra emissions can make the analyte signal harder to read. Spectral interference happens when emission lines or bands overlap. One way to reduce it is to improve instrument resolution. Another is to choose a different emission line for...

inductively coupled plasma atomic emission spectroscopy: principle

inductively-coupled-plasma-atomic-emission-spectroscopy-principle

ICP-AES Torch and Sample Analysis

Inductively coupled plasma atomic emission spectroscopy uses a plasma torch to analyze elements in a sample. This method is also called inductively coupled plasma optical emission spectroscopy, or ICP-OES. It is widely used because the plasma creates a strong environment for elemental analysis. The ICP source, or torch, contains three concentric quartz tubes. Argon gas flows through the tubes. A spark from a Tesla coil starts the ionization of argon and creates a high-temperature plasma. The...

inductively coupled plasma atomic emission spectroscopy: instrumentation

inductively-coupled-plasma-atomic-emission-spectroscopy

ICP-AES Instrument Types and Detection

Inductively coupled plasma atomic emission spectroscopy, or ICP-AES, uses an inductively coupled plasma to detect and analyze elements in a sample. The method measures the light given off by atoms, which helps identify and compare different elements. It is a common approach in atomic emission spectroscopy. ICP-AES instruments are built in three main forms: sequential, simultaneous multichannel, and Fourier transform instruments. Fourier transform designs are less commonly used, but they are...

atomic emission spectroscopy: lab

Plasma Sources in Atomic Emission Spectroscopy

Atomic emission spectroscopy uses plasma sources to identify elements by their light. The method creates abundant spectra with characteristic emission lines. Inductively coupled plasma, or ICP, is especially useful because it gives strong quantitative data. It works well under stable conditions, with low noise, low background, and few interferences. Newer air-operated microwave sources are also being studied. These sources may be more cost-effective than conventional ICP systems. Atomic...

atomic fluorescence spectroscopy

Measuring Elements by Atomic Fluorescence

Atomic fluorescence spectroscopy measures elements by detecting the light atoms give off after they are excited by electromagnetic radiation. The atoms are first placed in a flame, furnace, or plasma. They absorb energy, become excited, and then release that energy as they return to their original state. The emitted light is called fluorescence. The fluorescence is observed at a right angle to the incoming beam. This setup helps separate the emitted light from the light used to excite the...

flame photometry: overview

Flame Emission Spectrometry Basics

Flame emission spectrometry uses a flame to excite elements in a sample so their light can be measured. It is also called flame photometry. The method can be used for both qualitative and quantitative analysis of elements. The idea became established in the early 1860s when Kirchhoff and Bunsen showed that specific elements give off characteristic radiation in a flame. The first instrument for this purpose measured sodium in plant ash with a Bunsen flame. A major problem was how to add the...

flame photometry: lab

Flame Photometry and Metal Detection

Flame photometry is a method for detecting metals by measuring the light they emit in a flame. A solution such as potassium chloride is aspirated into the flame. The solvent evaporates first. The remaining salt becomes dehydrated and then dissociates into free gaseous atoms in the ground state. Some of these atoms absorb energy from the flame and move to an excited state. When they return to the ground state, they emit photons at characteristic wavelengths. These emissions are very narrow...

key terms and concepts

Learn how AAS uses hollow-cathode lamps and electrodeless-discharge lamps to match narrow wavelengths for accurate analyte detection and measurement.

Choosing Light Sources for AAS Measurements | JoVE K12

JoVE Core Analitik Kimya, karmaşık kimyasal prensiplerini anlaşılır, ilgi çekici animasyonlara dönüştürerek basitleştirir ve SI Birimlerinden NMR spektroskopisine kadar konuları daha erişilebilir ve anlaşılır hale getirir. Buna ek olarak, bilim insanlarının yer aldığı videolar, bu kavramların dünya çapındaki laboratuvarlarda yürütülen gerçek dünya araştırmalarındaki uygulamalarını gösterir.

analytical chemistry

the-principle-of-superposition-and-the-gravitational-field

The Principle of Superposition and the Gravitational Field

The principle of superposition applies to gravitational forces of objects that are sufficiently far apart. It states that the net gravitational force on a ...

/files/media/science-education/science-education-thumbs/14754.jpg

Escape Velocity

The escape velocity of an object is defined as the minimum initial velocity that it requires to escape the surface of another object to which it is ...

circular-orbits-and-critical-velocity-for-satellites

Circular Orbits and Critical Velocity for Satellites

The Moon orbits around the Earth. In turn, the Earth (and other planets) orbit the Sun. The space directly above our atmosphere is filled with artificial ...

energy-of-a-satellite-in-a-circular-orbit

Energy of a Satellite in a Circular Orbit

Thousands of artificial satellites orbit the Earth every day at various distances from the Earth. Satellites that orbit the Earth below an altitude of ...

Kepler's First Law of Planetary Motion

In the early 17th century, German astronomer and mathematician Johannes Kepler postulated three laws for the motion of planets in the solar system. He ...

Kepler's Second Law of Planetary Motion

In the early 17th century, German astronomer and mathematician Johannes Kepler postulated three laws for the motion of planets in the solar system. His ...

Kepler's Third Law of Planetary Motion

In the early 17th century, German astronomer and mathematician Johannes Kepler postulated three laws for the motion of planets in the solar system. In ...

Nuclear Fusion

The process of converting very light nuclei into heavier nuclei is also accompanied by the conversion of mass into large amounts of energy, a process ...

Nuclear Power

Controlled nuclear fission reactions are used to generate electricity. Any nuclear reactor that produces power via the fission of uranium or plutonium by ...

Nuclear Fission

Many heavier elements with smaller binding energies per nucleon can decompose into more stable elements that have intermediate mass numbers and larger ...

Nuclear Transmutation

Nuclear transmutation is the conversion of one nuclide into another. It can occur by the radioactive decay of a nucleus, or the reaction of a nucleus with ...

Atomic Structure

All matter is composed of atoms, the smallest individual units of elements. Each atom is made up of three subatomic particles: protons, neutrons, and ...

Radioactivity and Nuclear Equations

Nuclear chemistry is the study of reactions that involve changes in nuclear structure. The nucleus of an atom is composed of protons and, except for ...

Nuclear Stability

Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10&#8722;15 meters, a nucleus is ...

Students who demonstrate understanding can develop a model based on evidence to illustrate the life span of the sun and the role of nuclear fusion in the sun's core to release energy in the form of radiation.  Clarification Statement: Emphasis is on the energy transfer mechanisms that allow energy from nuclear fusion in the sun's core to reach Earth.  Examples of evidence for the model include observations of the masses and lifetimes of other stars, as well as the ways that the sun's radiation varies due to sudden solar flares ("space weather"), the 11-year sunspot cycle, and non-cyclic variations over centuries.  Assessment Boundary: Assessment does not include details of the atomic and sub-atomic processes involved with the sun's nuclear fusion.

3.3.9-12.A

Emission Spectra

When solids, liquids, or condensed gases are heated sufficiently, they radiate some of the excess energy as light. Photons produced in this manner have a ...

Atomic Spectroscopy: Absorption, Emission, and Fluorescence

Atomic spectroscopy is a vital tool in elemental analysis, both qualitatively and quantitatively. It can be broadly divided into optical spectroscopy, ...

Detection of Black Holes

Although black holes were theoretically postulated in the 1920s, they remained outside the domain of observational astronomy until the 1970s.
Their ...

space-time-curvature-and-the-general-theory-of-relativity

Space-Time Curvature and the General Theory of Relativity

In 1905, Albert Einstein published his special theory of relativity. According to this theory, no matter in the universe can attain a speed greater than ...

Schwarzschild Radius and Event Horizon

No object with a finite mass can travel faster than the speed of light in a vacuum. This fact has an interesting consequence in the domain of extremely ...

The Wave Nature of Light

The nature of light has been a subject of inquiry since antiquity. In the seventeenth century, Isaac Newton performed experiments with lenses and prisms ...

Nuclear Binding Energy

The difference between the calculated and experimentally measured masses is known as the mass defect of the atom. In the case of helium-4, the mass defect ...

Metal Flame Emission

Metal Flame Emission
Flame testing is an analytical technique where a sample is placed in a flame, and the characteristic flame color is used to identify ...

molecular-spectroscopy-absorption-and-emission

Molecular Spectroscopy: Absorption and Emission

Molecules possess discrete energy levels called quantum states. Unlike atoms, which have simpler energy levels, molecules possess additional rotational ...

Atomic Emission Spectroscopy: Instrumentation

The instrumentation of atomic emission spectrometry (AES) involves various components, including atomization devices that convert samples into gas-phase ...

Atomic absorption spectroscopy (AAS) relies on the Beer-Lambert law, which requires that the radiation source emits a narrow range of wavelengths to match ...

Students who demonstrate understanding can construct an explanation of the Big Bang theory based on astronomical evidence of light spectra, motion of distant galaxies, and composition of matter in the universe.  Clarification Statement: Emphasis is on the astronomical evidence of the red shift of light from galaxies as an indication that the universe is currently expanding, the cosmic microwave background as the remnant radiation from the Big Bang, and the observed composition of ordinary matter of the universe, primarily found in stars and interstellar gases (from the spectra of electromagnetic radiation from stars), which matches that predicted by the Big Bang theory (3/4 hydrogen and 1/4 helium).  Assessment Boundary:

Spectrophotometry: Introduction

Spectrophotometry is the quantitative measurement of the absorption, reflection, diffraction, or transmission of electromagnetic radiation through a ...

Atomic Emission Spectroscopy: Overview

Atomic emission spectroscopy (AES) is an analytical technique used to determine the elemental composition of a sample by analyzing the light emitted from ...

ultraviolet-and-visible-uvvis-spectroscopy-overview

Ultraviolet and Visible (UV&ndash;Vis) Spectroscopy: Overview

Ultraviolet&#8211;visible (UV&#8211;visible or UV&#8211;Vis) spectroscopy is an analytical technique that investigates the interaction between matter and ...

Atomic Emission Spectroscopy: Lab

AES is a powerful analytical technique, especially effective when used with plasma sources, producing abundant spectra in characteristic emission lines. ...

Flame Photometry: Overview

Flame photometry, also known as flame emission spectrometry, is a technique used for the qualitative and quantitative analysis of elements present in a ...

The Greek philosopher Democritus proposed that everything on Earth is made up of tiny particles called atomos, Greek for &#34;indivisible,&#34; from which ...

Students who demonstrate understanding can communicate scientific ideas about the way stars, over their life cycle, produce elements.  Clarification Statement: Emphasis is on the way nucleosynthesis, and therefore the different elements created, varies as a function of the mass of a star and the stage of its lifetime.  Assessment Boundary: Details of the many different nucleosynthesis pathways for stars of differing masses are not assessed.

3.3.9-12.C

Tidal Forces

The origin of Earth&#39;s ocean tides has been a subject of continuous investigation for over 2000 years. However, the work of Newton is considered to be ...

Students who demonstrate understanding can use mathematical or computational representations to predict the motion of orbiting objects in the solar system.  Clarification Statement: Emphasis is on Newtonian gravitational laws governing orbital motions, which apply to human-made satellites as well as planets and moons.  Assessment Boundary: Mathematical representations for the gravitational attraction of bodies and Kepler's Laws of orbital motions should not deal with more than two bodies, nor involve calculus.

3.3.9-12.D

Choosing Light Sources for AAS Measurements

Description

Transcript

Tags

More videos by Standards