LECTURE 1_Analytical Process Flashcards
It deals with methods for determining the chemical
composition of samples.
Analytical Chemistry
What is Analytical Chemistry?
It deals with methods for determining the chemical
composition of samples.
It is based on numbers (measurement or counting)
Quantitative data
Based on observations (involves the senses)
Qualitative data
Wet chemical methods such as precipitation, extraction, distillation, boiling or melting points, gravimetric and titrimetric measurements.
Classical Methods
Analytical measurements (conductivity, electrode potential, light absorption or emission, mass-to-charge ratio, fluorescence etc.) are made using instrumentation.
Instrumental Methods
Determine the mass of the analyte or some compound chemically related to it.
Gravimetric Methods
The volume of a solution containing sufficient reagent to react completely with the analyte is measured.
Volumetric Methods
Based on measurement of the interaction between electromagnetic radiation and analyte atoms or molecules.
Spectroscopic Methods
Separation techniques and quantitation is
based on calibration curve.
Chromatographic Methods
Involve the measurement of electrical properties
such as voltage, current, resistance and quantity of electrical charge.
Electroanalytical Methods
Plays a vital role in many research areas in chemistry, __________, __________, ___________, ____________, and the other sciences.
biochemistry, biology, geology, physics, and the other sciences.
It to refers to any chemical of interest.
Species
It occurs when a species other than analyte increases or decreases the response of the analytical method and makes it appear that there is more or less analyte than is actually present.
Interference
It is the transformation of an interfering species into a form that is notdetected.
For example, Ca2+ in lake water can be measured with a reagent called EDTA. Al3+ interferes with this analysis because it also reacts with EDTA. Al3+ can be masked with excess F− to form (AlF6)³–, which does not react with EDTA.
Masking
In ____________________, a sample is prepared and then analyzed to determine the concentration of one (or more) of its components
quantitative chemical analysis
the signal depends on the chemical properties of the sample
Classical analysis
- physical property of the sample is measured
- are capable of detecting individual atoms or molecules in a
sample! Analysis at the ppm (μg/mL) and even ppb (ng/mL) level
is routine
Instrumental analysis
The advantages of instrumental methods over classical methods include
- The ability to perform trace analysis
- Large numbers of samples may be analyzed very quickly.
- Many instrumental methods can be automated
- Most instrumental methods are multi-channel techniques
- Less skill and training is usually required to perform instrumental
analysis than classical analysis.
will generate but a single number for each analysis of the sample
Single-channel techniques
Single-channel techniques examples
include gravimetric and potentiometric analysis
Can obtain measurements while changing some independently
controllable parameter. It will generate a series of numbers for a single analysis.
Multi-channel techniques
Multi-channel methods have two important advantages over their singlechannel counterparts:
1. They provide the ability to perform multicomponent analysis. In other words, the concentrations of more than one analyte in a single sample may be determined.
2. Multi-channel methods can detect, and sometimes correct for, the presence of a number of types of interferences in the sample. If uncorrected, the presence of the interference will result in biased estimates of analyte concentration.
More than just identifying the presence of an interfering substance, multichannel data often allows the analyst to ____ for its presence
correct
