Technique Titration Measures Concentration Quantitative Yes Qualitative Sometimes

Technique: Titration Measures: Concentration Quantitative Yes Qualitative Sometimes: precipitation Sensitivity: Low Precision: Typically m. Molar. Depends on standards Accuracy: Depends on endpoint determination and standards Ease: Very simple Pro Very simple Con Need to know analyte. Limited sens/prec/acc

Technique: Titration Measures: Concentration Quantitative Yes Qualitative Sometimes: precipitation Sensitivity: Low Precision: Typically m. Molar. Depends on standards Accuracy: Depends on endpoint determination and standards Ease: Very simple Pro Very simple Con Need to know analyte. Limited sens/prec/acc

Technique: Electrochemistry: galvanic cell Measures: Concentration Quantitative Yes Qualitative No Sensitivity: good Precision: good Accuracy: good Ease: Simple Pro Measures current. Small devices Con Only for Re. Dox reactions. Need to know analyte

Technique: Electrochemistry: galvanic cell Measures: Concentration Quantitative Yes Qualitative No Sensitivity: good Precision: good Accuracy: good Ease: Simple Pro Measures current. Small devices Con Only for Re. Dox reactions. Need to know analyte

Technique: Electrochemistry: ion selective electrode Measures: Concentration Quantitative Yes Qualitative No Sensitivity: good Precision: good Accuracy: Limited by interference Ease: Simple Pro Measures current Con Only for Re. Dox reactions. Need to know analyte

Technique: Spectrophotometry: UV-VIS absorption Measures: Concentration Quantitative Yes Qualitative Spectral signature Sensitivity: Moderate Precision: Moderate (contamination) Accuracy: Moderate (need to subtract blank) Ease: Simple Pro Molecule specific Con Need rather pure sample and know spectrum

Technique: Spectrophotometry: UV-VIS absorption Measures: Concentration Quantitative Yes Qualitative Spectral signature Sensitivity: Moderate Precision: Moderate (contamination) Accuracy: Moderate (need to subtract blank) Ease: Simple Pro Molecule specific Con Need rather pure sample and know spectrum

Technique: Spectrophotometry: Atomic flames Measures: Concentration Quantitative Yes Qualitative Element specific Sensitivity: Good Precision: Better in absorption than in emission (T) Accuracy: Good Ease: Yes Pro Specificity Con Only elemental

Technique: Spectrophotometry: Atomic flames Measures: Concentration Quantitative Yes Qualitative Element specific Sensitivity: Good Precision: Better in absorption than in emission (T) Accuracy: Good Ease: Yes Pro Specificity Con Only elemental

Technique: Mass spectrometry Measures: mass Quantitative Somewhat with standards Qualitative Molecular identification Sensitivity: Very good (sometimes attomoles) Precision: Resolution 500 -106 (FT-ICR) Accuracy: Depends on resolution and calibration Ease: Complex apparatus Pro Sensitive. Informative Con Complex. More qualitative than quantitatve

Technique: Mass spectrometry Measures: mass Quantitative Somewhat with standards Qualitative Molecular identification Sensitivity: Very good (sometimes attomoles) Precision: Resolution 500 -106 (FT-ICR) Accuracy: Depends on resolution and calibration Ease: Complex apparatus Pro Sensitive. Informative Con Complex. More qualitative than quantitatve

Technique: Chromatography Measures: Separation of compounds Quantitative With internal standards Qualitative Yes but need more information Sensitivity: Very good; depends on detector Precision: Resolution increases with square root of length Accuracy: See resolution, depends on standards Ease: Routine Pro Ubiquitous and routine Con Needs combination with other info, e. g. GC-MS

Technique: Chromatography Measures: Separation of compounds Quantitative With internal standards Qualitative Yes but need more information Sensitivity: Very good; depends on detector Precision: Resolution increases with square root of length Accuracy: See resolution, depends on standards Ease: Routine Pro Ubiquitous and routine Con Needs combination with other info, e. g. GC-MS

Technique: NMR Measures: Molecular structure Quantitative No Qualitative Yes Sensitivity: Low Precision: High Accuracy: High Ease: Complex apparatus Pro Detailed structure info Con Expensive, low sensitivity

Technique: X-Rays Measures: Structure Quantitative No Qualitative Yes Sensitivity: Good but needs crystal Precision: Very good Accuracy: Very good Ease: Sample prep. Sophisticated analysis Pro Detailed structure information Crystal growth. Complexity

Technique: Microscopy Measures: Geometry Quantitative No Qualitative Yes Sensitivity: New techniques for single molecule Precision: STM>electon microscopy>Optical Accuracy: Ease: Sophisticated apparatus Pro Detailed Con Not quantitative. Interpretation can be difficult

Technique: DNA Sequencing Measures: DNA sequence Quantitative No Qualitative Yes Sensitivity: Single DNA by PCR Precision: Very high Accuracy: Limited by genetics statistics only Ease: Robotic automation Pro Sensitive and specific Con Need to match

Surface analytical techniques • UPS • XPS • LEED • AUGER • Second harmonic generation • SIMS • SERS http: //www. udel. edu/chem/beebe/surface. htm http: //www. uksaf. org/tech/list. html

Immunoassays Selection by specific antibody-antigen affinity Novel “Micro” techniques • Single molecule fluorescence microscopy • Biosensors • Nanotech sensors • Microfluidics

Novel “Micro” techniques • electronic nose

Novel “Micro” techniques • electronic nose I ~ f (receptor DQ) Nov 14, 2003 Nanotube sensor detects nerve agents Researchers in the US have made a nerve agent detector usingle-walled carbon nanotubes. Eric Snow and colleagues at the Naval Research Laboratory (NRL) in Washington say that their device is simple to fabricate, extremely sensitive and intrinsically selective to specific gases. The sensor could be used in industrial and military applications (J Novak et al. 2003 Appl. Phys. Lett. 83 4026). Chemical and nucleic acid receptors Figure 1. Gate-biased nanowire sensor

Novel “Micro” techniques • Confocal microscope

Novel “Micro” techniques • FRET

Novel “Micro” techniques • biosensors Kevin Plaxco, UCSB

Novel “Micro” techniques • biosensors Kevin Plaxco, UCSB

Neutron activation and the past…