AA & ICMPMS

When collecting for trace elements, what do you want avoid on the collection supplies?

Want to make sure they are free from metals as much as possible

What tube to use when collecting whole blood?

Royal blue top with EDTA

What tube to use when collecting serum?

Royal blue top no additive

What tube to use when collecting urine?

Sarstedt (UAH) or any approved container

What should be done if there are multiple collections needed with the trace elements?

Collect trace elements following protocol to prevent contamination from other tubes

What is the Sample Introduction System composed of?

Nebulizer and spray chamber to allow the samples to get into the instrument

How does the Sample Introduction System allow sample to go through?

Small droplets of sample will enter the torch while the larger droplets are discarded

What is the ICP Torch and RF coil?

It generates the argon plasma with temperature of 6000C

What is the ion source in ICP-MS?

Argon

How does the ICP torch and RF coil work?

The liquid droplets containing the sample enter the torch and are dried to a solid then heated into a gas. As the gas continues to travel, they absorb more energy and release an electron to form single charged ions

What is the Interface?

Links the ICP ion source to the high vacuum mass spectrometer

What is the Vacuum System?

Provides high vacuum for ion optics, quadruple, and detector

What is the interference that can be caused from the plasma ion source and the analyte ion?

They may carry the same mass to charge (m/z) ratio

ArO+ and Fe both are 56

What is one way to prevent the interference of same m/z?

Mathematical calculations or using a cell before it enters the mass spect

What is a Standard Mode cell?

Where all ions pass through to mass spectrometer

What is a Collision Mode Cell?

It uses Kinetic Energy Discrimination to remove the interferent

What is the theory behind the Collision Cell?

Use the size of the interferent (ion source) and it will collide with inert gas more frequently and it will lose more energy so it can no longer pass the barrier

What is a disadvantage of using the collision cell?

The analyte signal may decrease alongside the background interfence so it s not ideal for low concentrations of analyte

What is the theory behind Reaction Cell?

The interferent is removed based on chemical reaction where it produces an exothermic reaction with a reactive gas. This renders it neutral and gets ejected from the cell

What is an advantage with using a reaction cell?

The background decreases but analyte signal is preserved

What is the purpose of ion optics?

It guides the ions of interest into quadruple while preventing the neutral species and photons from entering

What is the purpose of the mass spectrometer?

Sorts ions based on m/z

What is the purpose of the detector?

Acts as an electron multiplier and counts the ions exiting quadruple

What is the purpose of the data handling ?

Controls instrument data to obtain final concentration results

What is the principle behind Mass Shift Tandem MS?

The analyte will enter Q2 and react with the gas to turn into a different ion. The new ion m/z is selected for in Q3 and interferences will not pass through

What is the principle of On Mass Tandem MS?

The interference will enter Q2 and react with the gas to turn into a different ion. Q3 will select the m/z of analyte of interest and does not allow the interference to pass through

What is Atomic Absorption?

An analytical method for determining the concentration of metal and semi-metallic element in various matrices

What is the theory behind atomic absorption?

Free atoms absorb light at a certain wavelength when they move from ground state. The number of atoms present is proportional to the amount of light absorbed

What is the Hollow-Cathode Lamp?

Hollow shape lamp lined with the pure metal of the element/analyte of interest

Example: line with copper if interested in detecting copper levels

How does the hollow-cathode lamp work?

Electrical potential between cathode and anode will ionize the gas (neon/argon) and the gas will travel to cathode leading to the lined element being released. Once it is released, the atoms will get excited and as they fall to ground state, radiant energy will be released for the sample to absorb

What is Sputtering?

The continuous release of metals atoms from the surface of the cathode

How is the sample introduced into the instrrument?

It goes through the light source using a nebulizer where it turns into a fine mist. Small droplets will pass through while bigger ones will fall away

What happens to the sample during its introduction?

When it enters the flame, the solvent will evaporate leaving element of interest. It will then dissociate from its chemical bonds and get placed in ground state

What is the principle behind the Total Consumption Burner?

The fuel, oxidant, and sample are passed through separate channels to a single opening where the flame is. The entire mix will pass through the flame but only the small droplets will dry and burn

What is the principle behind using Premix burner?

The fuel, oxidant, and sample are mixed in the chamber before entering the flame. Big droplets in the mixing chamber are collected on the wall and drain out while only the small droplets will pass through the flame

What is the disadvantage of using Total Consumption Burner?

It has more background noise as it cannot get rid of big droplets efficiently but there is less carryover

What is used in a total consumption burner?

Combination of air-hydrogen is used

What is used in the premix burners?

Combination of air acetylene or nitrous oxide acetylene

What is emission interference?

The light emitted by excited atoms will have the same wave length as the incident light and it enhances the signal received by the detector

What is a chopper?

It produces a pulsed beam of incident light from the lamp so the detector does only gets the steady beam from the excited atoms of interest

What are the two Flameless Atomic Absorption?

Cold vapoour generation Assembly and Graphite furnace

What element is cold vapour mercury used for?

Only for Mercury analysis

What is the principle behind cold vapour mercury analysis?

Sample is decomposed by nitric acid then reducing agent (sodium borohydride) converts mercury to its elemental state. A stream of gas is bubbled and pushes the mercury into a sealed cell

What is the principle behind the Graphite Furnace?

Sample is placed on a solid support then heated to a drying temperature, charring temperature, then an atomization temperature

What is the Drying Stage and what temperature does it happen at?

100-120C and the solvent is removed from the sample

What is the Ashing/Charring Stage?

Organic or inorganic material is removed at 400-800C

What is the Atomization Stage?

Free atoms are generated and signal is produced to a sharp peak which can be related to amount of analyte present. It is heated up to 2600C

What is the purpose of the monochromator?

It isolates the pure radiant and prevents other wavelengths from reaching the tube

What is the purpose of the photomultiplier tubes?

Converts radiant energy into a signal and amplifies the signal into the recorder

What is the principle behind the photomultiplier tube?

Electrons are drawn toward the dynode and releases even more electrons when it strikes the dynode to increase the signal several thousand fold

What is the main advantage over ICP MS?

It allows for multi-analyte analysis, increased sensitivity, less sample needed and less sample preparation

What is a disadvantage with ICP-MS?

It is expensive to purchase

When might Atomic Absorption be more cost effective than ICP?

If only one analyte will be tested since AA is cheaper