Technique: Titration

Measures: Concentration

Quantitative Yes

Qualitative Sometimes: precipitation

Sensitivity: Low

Precision: Typically mMolar. 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 mMolar. 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 ReDox 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 ReDox 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 ReDox 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

Con 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

Novel “Micro” techniques

• Single molecule fluorescence microscopy• Biosensors• Nanotech sensors• Microfluidics

Immunoassays

Selection by specific antibody-antigen affinity

Novel “Micro” techniques• electronic nose

Novel “Micro” techniques

• electronic nose

Nov 14, 2003Nanotube sensor detects nerve

agentsResearchers in the US have made a

nerve agent detector using single-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).

I ~ f (receptor Q)

Chemical and nucleic acid receptors

Chemical and nucleic acid receptors

Figure 1. Gate-biased nanowire sensor

Novel “Micro” techniques• Confocal microscope

Novel “Micro” techniques• FRET

Novel “Micro” techniques• biosensorsKevin Plaxco, UCSB

Novel “Micro” techniques• biosensorsKevin Plaxco, UCSB

Neutron activation and the past…