INDUCTIVELY COUPLED PLASMA-ATOMIC EMISSION SPECTROSCOPY

PRESENTED BYP.ANURADHA

M.PHARMACYPHARMACEUTICAL ANALYSIS&QA

SEMINAR ON

Introduction:

Atomic emission spectroscopy (AES or OES) uses quantitative measurement of the optical emission from excited atoms to determine analyte concentration.

EMISSION SOURCES:

• Flames

• Arcs / Sparks

• Direct Current Plasmas (DCP) Plasma sources• Inductively Coupled Plasmas (ICP)

• Microwave induced Plasmas(MIP)

Inductively coupled plasma atomic emission spectroscopy (ICP-AES), also referred to as inductively coupled plasma optical emission spectrometry (ICP-OES) - is a type of emission spectroscopy that uses the inductively coupled plasma to produce excited atoms and ions that emit electromagnetic radiation at wavelengths characteristic of a particular element.

Principle

Sample solution containing elements

Formation of liquid droplets

DESOLVATION

atomizationexcitation

Emission of Radiation at a Specific Wave Length

Measure the intensity of emitted radiation

INSTRUMENTATION

ICP-AES utilizes a plasma as the atomization & excitation source. A plasma is an electrically neutral , highly ionized gas that consists of ions

electrons&atoms. The energy that maintains an analytical plasma is derived from an electric or

magnetic field.

NEBULIZERS: Nebulizers are devices that convert a liquid into an aerosol that can be transported to the plasma.

TYPES OF NEBULIZERS Concentric nebulizer Micro concentric nebulizer Cross flow nebulizer Babington nebulizer

PUMPS:

Peristaltic pumps are almost exclusivelythe pumps of choice for ICP-AES.

• The pumps utilize a series of rollers thatpush the sample solution through the tubingusing a process known as peristalsis.

• With a pumped solution, the flow rate ofthe solution into the nebulizer is fixed and isnot as dependent on solution parameters suchas viscosity and surface tension.

SPRAY CHAMBER:

A spray chamber is placed between the nebulizer & the torch.

The primary function of the spray chamber is to remove large droplets from the aerosol.

The secondary purpose is to smooth out pulses that occur during nebulization due to pumping of the solution.

It is designed to allow droplets with diameters of about 10 micrometre or smaller to pass to the plasma.

ICP TORCH:

DETECTION:2 types of detection-Viewing Positions

SOP: Side-on-Plasma EOP: End-on-Plasma

more suitable for hard matrices (concentrated samples);

alkali metals (Na, K, Li) calibration is more linear;

less spectral interferences;

lower sensitivity (Limit-of-Detection is higher);

more suitable for light matrices;

alkali metals (Na, K, Li) calibration is less linear;

more spectral interferences;

higher sensitivity (Limit-of-Detection is lower);

HOW TO PERFORM SIMULTANEOUS ANALYSIS

Spectrometers: Function-To isolate specific spectral lines emitted from the analyte from all of the other emissions produced by the other atoms,ions&molecules within plasma.

There are several devices available Monochromators

Simultaneous analysis was carried out by using: Polychromators , which are Paschen-Runge optics coupled to highly sensitivity

detectors known as Photomultiplers(PMT). Echelle grating optics, coupled to solid state detectors(CCD,CID) also known as

Charge transfer devices.

a. light passes through the entrance slit.b. It is reflected off a collimating mirror on to a diffracting grating.c. As the grating rotates the light separates into its different spectral components,and passes the desired wavelength to the second collimating mirror. d. The monochromatic light focuses on to exit slit positioned in front of the detector.

Spectrometers-monochromator

Spectrometers- Echelle spectrometer

PMT is to convert optical rotation(photons) into an electrical signal(electrons).The vaccum tube devices are very sensitive&cover a large wavelength range. It consists of a vaccum photocell with an anode, photocathode and a number of dynodes which have an increasingly positive potential with respect to the photocathode.

Detector- Photomultipler tubes(PMT)

Clinical Analysis: metals in biological fluids (blood, urine).

Environmental Analysis: trace metals and other elements in waters, soils,

plants, composts and sludges.

Pharmaceuticals: traces of catalysts used; traces of poison metals (Cd, Pb etc).

Industry: trace metal analysis in raw materials; noble metals determination.

Forensic science: gunshot powder residue analysis, toxicological examination

( e.g., thallium (Tl) determination.

ICP-AES-Application

Boss, C.B. and Freden, K.J. Concepts, Instrumentation and Techniques in Inductively Coupled Plasma Optical Emission Spectrometry. 1997

Skoog, D. Fundamentals of Analytical Chemistry, 2004

Inductively Coupled Plasmas in Analytical Atomic Spectrometry; Montaser, A.; Golightly, D. W., Eds.; VCH Publishers: New York, 1988

Fredeen, C. B. (n.d.). http://www.atoomspectrometrie.nl/Icpconceptsbook.pdf.

Bibliography