HP 4500 Series ICP/MS features low uptake cross flow nebulizer, platinum interface cones as standard, two separately controlled mass flow controllers for the carrier and blend gas supplies, long life Shield Torch System, twin peristaltic pumps, quartz double pass spray chamber, Peltier cooled spray chamber, mass flow controlled carrier gas supply, turbo pumped three-stage vacuum system, and Omega lens ion optics. Comes with Auto sampler, and front end ISCO sample introduction, and cooling unit. System includes, Software, Computer, Monitor, manual. This system is totally complete and ready to go.

ICP-MS

ICP-MS (Inductively Coupled Plasma Mass Spectrometry) is a type of mass that is highly sensitive and capable of analysis of a range of metals and several non-metals at below one part in 1012. It is based on coupling together an inductively coupled plasma as a method of producing ions with a mass spectrometer as a method of identifying and detecting the ions

Categories

· ICP - this is a high temperature plasma (partly ionized argon) sustained with a radio frequency electric current, which acts to produce ions. The electric current is transferred to the plasma by an induction coil, wrapped around a configuration of concentric quartz tubes (the plasma torch). The common operating frequencies are 27.12 and 40.68 MHz and operating power is in the range between 800 and 1500 W. The plasma is sustained within a constant flow of argon gas, open to atmosphere and reaches temperatures as high as 10,000 K in the hottest part. To prevent melting of the torch a high flow rate of argon is used in the outermost tubing. The total gas consumption of a typical analytical ICP is in the range of 14 - 18 L/min. In order to reduce capacititive coupling between the coil and plasma, some designs employ an additional metal sheet between the torch body and the induction coil.

· MS - the ions from the plasma are extracted through a series of cones into a mass spectrometer, usually a quadrupole. The ions are separated on the basis of their mass-to-charge ratio and a detector receives an ion signal proportional to the concentration.

The concentration of a sample can be determined through calibration with elemental standards. ICP-MS also lends itself to quantitative determinations through isotope dilution, a single point method based on an isotopically enriched standard.

Other mass analyzers coupled to ICP systems include double focusing magnetic-electrostatic sector systems with both single and multiple collector, as well as time of flight systems (both with axial and orthogonal accelerators).

Another type of spectrometer using ICP is ICP-AES (Atomic Emission Spectrometer).

There is an increasing trend of using ICP-MS as a tool in Speciation Analysis, which normally involves a front end chromatograph separation and an elemental selective detector, such as AAS and ICP-MS. For example, ICP-MS may be combined with size exclusion chromatography and quantitative preparative native continuous polyacrylamide gel electrophoresis (QPNC-PAGE) for elucidating native metal cofactor containing proteins in biofluids.

Instrument operation

A sample is injected into the instrument, normally by an auto sampler. The Sample is atomized and delivered through a glass tube by an argon carrier gas. The sample is then exposed to radio frequency, which converts the gas into plasma. A fraction of the plasma passes through a ~1mm hole and then a ~0.4mm hole. The purpose of which is to allow a vacuum that is required by the mass spectrophotometer. The sample then passes through charged lenses through the quadrapole and into the detector.

Plasma Generation

As stated above the mode of ionization is via an argon plasma. Argon has the advantage of being abundant (in the atmosphere, as a result of the radioactive decay of potassium). It is therefore available more cheaply than the other inert gases. Argon also has the advantage of having a higher first ionization potential than all other elements except He, F and Ne.

The radio frequency causes the following reaction: Ar › Ar+ + e-. Given the high ionization potential as cited above reverse reaction will take electrons from any species. This recombination of Ar with an electron Ar+ + e- › Ar is likely to cause the loss of an electron from a metal M › M+ + e-. Group II metals may become doubly charged species due to their low second ionization potential.

Elemental Analysis

The ICP-MS allows analysis of elements with mass ranges 7 to 250. This encompasses Li to U. Some masses are prohibited such as 40 due to the abundance of argon in the sample. A typical ICP-MS will be able to detect in the region of ppt to 10 or 100 ppm or around 8 orders of magnitude.

Unlike Atomic Absorption Spectroscopy which can only scan for a single element at a time ICP-MS has the capability to scan for all elements simultaneously. This allows rapid sample processing.

Usage

ICP-MS can be used for analysis of environmental samples such as water and various other non-particulate samples. The instrument can also analyze for metals in urine in the case of mining activities. The instrument is very sensitive to particulate matter and high concentrations of organics will cause the instrument to cease function, requiring cleaning.

Mass spectrometry

Basic schematic of a mass spectrometer

Mass spectrometry (also known as mass spectroscopy (deprecated)[1] or in common speech "mass-spec") is an analytical technique used to measure the mass-to-charge ratio of ions. It is most generally used to find the composition of a physical sample by generating a mass spectrum representing the masses of sample components. The technique has several applications, including:

· Identifying unknown compounds by the mass of the compound molecules or their fragments

· Determining the isotopic composition of elements in a compound

· Determining the structure of a compound by observing its fragmentation

· Quantifying the amount of a compound in a sample using carefully designed methods (mass spectrometry is not inherently quantitative)

· Studying the fundamentals of gas phase ion chemistry (the chemistry of ions and neutrals in vacuum)

· Determining other physical, chemical or even biological properties of compounds with a variety of other approaches

A mass spectrometer is a device that measures the mass-to-charge ratio of ions. This is achieved by ionizing the sample and separating ions of differing masses and recording their relative abundance by measuring intensities of ion flux. A typical mass spectrometer comprises three parts: an ion source, a mass analyzer, and a detector system.

Simplified working example

Different compounds have different atomic masses, and this fact is used in a mass spectrometer to determine what chemicals are present in a sample. For example, table salt (NaCl), is vaporized (turned into gas) and ionized (broken down) into electrically charged particles, called ions, in the first phase of the mass spectrometry. The sodium ions and chloride ions have specific atomic weights. They also have a charge, which means that their path can be controlled with an electric or magnetic field. The ions are sent into an acceleration chamber and passed through a slit in a metal sheet. A magnetic field is applied to the chamber. The field pushes each ion perpendicular to the plane defined by the particles direction of travel and the magnetic field lines. They are then deflected (makes them curve instead of traveling straight) onto a detector. The lighter ions are deflected more than the heavier ions because according to Newton's second law of motion the acceleration of a particle is inversely proportional to its mass. Likewise, the magnetic field can push the lighter ions further, thereby giving them a larger deflection, than the heavier ions. The detector measures exactly how far each ion has been deflected, and from this measurement, the ion's 'mass-to-charge ratio' can be worked out. From this information it is possible to determine with a high level of certainty the chemical composition of the original sample.

This example was of a sector instrument, however there are many types of mass spectrometers that not only analyze the ions differently but also produce different types of ions; however they all use electric and magnetic fields to change the path of ions in some way.

Instrumentation

Ion source

The ion source is the part of the mass spectrometer that ionizes the material under analysis (the analyte). The ions are then transported by magnetic or electric fields to the mass analyzer.

Techniques for ionization have been key to determining what types of samples can be analyzed by mass spectrometry. Electron ionization and chemical ionization are used for gases and vapors. In chemical ionization sources, the analyte is ionized by chemical ion-molecule reactions during collisions in the source. Two techniques often used with liquid and solid biological samples include electrospray ionization (due to John Fenn) and matrix-assisted laser desorption/ionization (MALDI, due to K. Tanaka and separately, M. Karas and F. Hillenkamp). Inductively coupled plasma sources are used primarily for metal analysis on a wide array of samples types. Others include fast atom bombardment (FAB), thermospray, atmospheric pressure chemical ionization (APCI), secondary ion mass spectrometry (SIMS) and thermal ionisation.