INDUCTIVELY COUPLED PLASMA MASS SPECTROMETER (ICP-MS) 29-09-2012
OVERVIEW• INTRODUCTION• INSTRUMENTATION• PRINCIPLE Sample introduction Ion source Mass analysers Detection unit Peak measurement Methods of quantitation Interferences• PHARMACEUTICAL APPLICATIONS• NEXT GENERATION OF ICP-MS• CONCLUSIONS
INTRODUCTION What is ICP-MS? Inductively Coupled Plasma Mass SpectrometryElemental analysis with:• Wide elemental coverage• Very low detection limits(ppt /ppm)• Fast analysis times (all elements at once)• Simple spectra• Isotopic information
Why is ICP-MS unique? ICP-MS can:• measure almost any element at ppt to ppm levels in almost any material.• measure all elements in a single analysis.• distinguish different element species (speciation). Main requirements in pharmaceutical analysis are:• high sensitivity• good matrix tolerance• low levels of interferences• ease of coupling to speciation techniques ( LA, LC and maybe GC)
INSTRUMENTATION 2 METALLIC CONES (SAMPLER AND SKIMMER CONE ( 0.6-1.2mm ORIFICE, AT 760 TORR) TO SEPARATE FINE DROPLETS (1-2%)FROM LARGER ONES USING PERISTALTIC PUMP(1ml/min) 750-1500W
PRINCIPLE• Liquid samples to form aerosol in nebulizer.• Introduction of Argon to the ICP torch, which is located in center of a radio frequency (RF) coil for energy supply.• RF field causes collisions of Ar atoms, generating a high-energy plasma.• Sample aerosol decomposed in plasma (6000 - 10000 K) to form analyte atoms which are simultaneously ionized.• Ions extracted from the plasma into mass spectrometer region.
MASSANALYSERS 1.QUADRUPOLE MASS SPECTROMETER • dc field on one pair of opposite rods and RF field on the other pair. • Ions of a selected m/z ratio are allowed to pass through the rods of the detector.
PEAK MEASUREMENT MEASUREMENT VARIABLES:• Whether it is a continuous or transient signal.• The temporal length of the sampling event.• Volume of sample available.• Number of samples being analyzed.• Number of replicates per sample.• Number of elements being determined.• Detection limits required.• Precision/accuracy expected.• Dynamic range needed.• Integration time used.
INTERFERENCES• Polyatomic Interferences Minimized by:1. Optimization of nebulizer gas flow (1.5-1.8ml/min).2. RF power adjustment (500-800W).3. Sampling position within plasma.• Isobaric Interferences Minimized by:1. cold plasma technique2. collision/reaction cell3. High resolution mass analysers as double focussing magnetic field sector.• Matrix Interferences Minimized by: use internal standardization
FIELDS OF APPLICATIONS• Qualitative and Quantitative (simultaneous multi element analysis).• Isotope ratio measurement• Coupling techniques: Chromatographic system Laser ablation
LC-ICP-MS Advantages of HPLC ICP-MS as detector• Wide applicability • Selective for the element• High resolution • Provide isotopic information• Rapid analysis • Determination of multiple• High sensitivity elements simultaneously• High reproducibility • Universal ,regardless the mode of• Quantitative chromatography• Easily automated • Extremely sensitive • Detection limits in ppt range
ABLATION ICP-MS Analysis of solid sample surfacesProcedure:• Laser beam focused onto sample surface in ablationchamber or cell.• Miniature plasma above sample ablates material fromsurface.• Resultant particulate material is transported to ICP-MSwith carrier gas stream (e.g. Ar)• Sample is decomposed, atomised and ionized in ICPplasma and analyzed in mass spectrometer. Applications for LA-ICP-MS: • Monitor distribution of administered drugs among different tissues and body compartments. • In-situ analysis of metals and other elements in samples separated using PAGE, e.g.: – Au and Pt drug metabolite identification. – Determine degree of phosphorylation of different separated proteins.
PHARMACEUTICAL APPLICATIONS• Pharmaceutical waste water• Drug discovery / drug development: Analysis of individual forms of drug compounds using target element analysis Simple metal analysis during development of metal-based drugs• QA/QC and process development: National Pharmacopeia (e.g. USP, EP, JP) Testing Impurity limit tests Metals in active pharmaceutical ingredients (API) QC of natural products – toxic impurities Toxic element impurities (e.g. heavy metals)• Clinical trials: Simple metal analysis for active component confirmation Monitoring of the metabolites of an administered drug
• Metal impurities – Leachables from pharmaceutical packaging materials1. Interaction between formulation and packaging material results incomponents migrating into the drug product.2. These components may be toxic or affect the stability of the drug product3. Storage conditions impact leaching (heat, UV radiation, storage time)Typical leachables are:• Small organic molecules [monomers, excipients, reaction by-products],• Metal ions and trace elements (e.g. aluminum, cadmium, chromium, copper, lead, manganese, and zinc)• Metal ions can affect the stability of the formulation, catalyze the degradation of the active pharmaceutical ingredient (API) and cause unqualified degrades toform, or pose a toxicity threat on their own.
NEXT GENERATION OF ICP-MS (NexION 300 ICP-MS Instruments)• Engineered to deliver a level of stability, flexibility and performance never before seen in an ICP-MS instrument, PerkinElmers NexION® 300 is the first truly significant and revolutionary industry advancement in recent years.
The NexION 300 offers:• 3 modes of operation (Standard, Collision and Reaction) and can be quickly switched from 1 mode to another.• So, every analysis can be performed on the same instrument.• Its the only ICP-MS that lets you maximize productivity without compromising sensitivity or performance.• A single ICP-MS instrument offers both the simplicity and convenience of a collision cell and the exceptional detection limits of a true reaction cell.• Stability is optimized by incorporating a unique Triple Cone Interface and Quadrupole Ion Deflector. Designed to remove an unprecedented level of un- ionized material (and preventing it from entering the Universal Cell), this innovative ion path keeps the instrument clean, minimizing drift and eliminating the need for cell cleanings.
Features/Benefits• Large, accessible sample introduction system• Low liquid uptake nebulizer• Free-running RF plasma generator• Automated X, Y, Z torch positioning• Patented PlasmaLok® technology• Fastest scanning quadrupole in the industry• Quadrupole Ion Deflector• Triple Cone Interface• Plasma View window• Four-stage vacuum system• Benchtop design
APPLICATIONS• Gold Nanoparticles Reference Materials Using the NexION 300 ICP-MS in Single Particle Mode.• Coupling Flow Field Flow Fractionation to ICP-MS for the Detection and Characterization of Silver Nanoparticles.• The Determination of Lead in Calcium-Based Antacid and Dietary Supplements.• The Determination of Metals in Cosmetics.• Assuring safety of traditional Chinese herbal medicines by monitoring inorganic impurities using ICP-MS.
CONCLUSIONS• ICP-MS is excellent detector for HPLC in bioanalysis.• Orthogonal to other detectors.• Rapid and efficient method for metabolism studies /speciation.• Polyatomic interferences from high matrix samples are a major challenge.• Room for instruments improvements.