Analytical Chemistry Flashcards
specie of special interest
analyte
performed either through wet-analysis or instrumental methods
Analytical methods
part of the sample outside the analyte
matrix
usually employs precipitation, titrimetric, and gravimetric methods
wet-analysis
uses sophisticated instruments capable of measuring the analyte’s physical and chemical properties
Instrumental methods
renders the sample usable for the succeeding analyses as its composition are kept intact; true for some instrumental analyses
Non-destructive analysis
ends up consuming the sample or renders it unusable for the succeeding analyses; true for all, if not most, wet analyses
Destructive analysis
determines only a limited number of specie in the sample
proximate or partial
determines the amount of each element in the sample regardless of composition
ultimate
determines the amount of each element in the sample present per composition
complete
separation via precipitation, extraction or distillation
classical methods
separation via chromatography and electrophoresis
instrumental methods
representative sample obtained at the sampling site
gross sample
homogenized gross sample brought in the laboratory
laboratory sample
portion of the laboratory sample used in the actual test method
analysis sample
converts any interfering specie into non-detected form
masking
done by precipitation, extraction, electrodeposition, ion-exchange, volatilization or chromatography
separation
process of standardizing output or instrument readout
calibration
a plot of instrument response as a function of concentration
calibration curve
a given amount of sample is “spiked” with a known amount of standard and any increase in signal due to the added standard is observed
standard addition
analysis of reference materials or samples of known concentration
accuracy
analysis of replicate samples
precision
analysis of matrix spikes
extraction efficiency
analysis of blanks
contamination
Establishes the baseline of an analytical instrument, in the absence of sample
System or Instrument blank
To measure the amount of the analytical signal which arises from the dilution solvent.
Solvent or Calibration blank
To detect contamination from reagents, sample handling, and the entire analytical process
Method blank
To detect contamination from field handling, transportation, or storage
Matched-matrix blank
To detect contamination in sampling media such as filters and sample adsorbent traps
Sampling media or trip blank
To determine contamination of equipment and assess the efficiency or equipment clean-up
procedures
Equipment blank
also known as systematic error, are non-random (or consistent) error that can be detected and corrected
determinate errors
also known as random error, arise from the effects of uncontrollable variable in the measurement
indeterminate
used to determine whether there is a significant difference between the results of two different methods based on their standard deviations
f-test
