Nature And Scope Of Analytical Chemistry Flashcards
Processes that provide the basis for analytical measurements. It is any physical or chemical principle that can be used to study an analyte
Techniques
Detailed set of instructions for a particular analysis using a specified technique
Method
Set of written instructions for a particular analysis using a specified technique
Method
Set of written instructions on how to apply a method to a particular sample
Procedure
Set of written guidelines for the analysis of sample specified by an agency
Protocol
Match the following chemical and physical properties to the instrumental method used.
- Spectroscopy
- Coulometry
- Mass spectrometry
- Thermal gravimetry, DTA, DSC
- Potentiometry
- Amperometry, polarography
- Kinetic methods
- Activation and isotope dilution methods
A. Absorption of radiation
B. Radioactivity
C. Electrical potential
D. Thermal characteristics
E. Electrical Charge
F. Mass-to-charge ratio
G. Electrical Current
H. Rate of reaction
1A
2E
3F
4D
5C
6G
7H
8B
Sample that contains all the components of the matrix except the analyte
Blank
Experimental measurement that is proportional to the analyte concentration
Signal
The grade or purity of chemicals has a significant effect on the ____ in any analysis.
Accuracy
Highest purity chemical grade (≥95%)
ACS Grade
Usually solutions or dilutions of ACS grade materials
Reagent or Analytical Reagent (AR) Grade
Meets or exceeds requirements set by the US Pharmacopeia
USP grade
Meets or exceeds requirements set by the National Formulary
NF grade
Relatively high quality with exact levels of impurities unknown. Used for educational purposes
Laboratory grade
Chemicals with <90% purity. Often supplied in bulk for industrial or commercial applications
Technical or Commercial Grade
Type of analysis including macro, meso, micro, ultra micro is according to ___
Amount of sample
Errors and uncertainties are possible to eliminate in any chemical analysis. True or false.
False
_______ is an indication of the reproducibility (repeatability) of measurement, while ______ is a measure of agreement between an experimental result and an expected (or true) value.
Precision, Accuracy
Type of error that causes the data to be more scattered more or less symetrically around the mean. It is inherent to any type of analysis.
Random (indeterminate) error
Type of error that causes mean of a set of data to differ from the accepted value. May lead to bias in measurement results
Systematic (determinate)
These errors are often large, and may cause a result to be either high or low. This often leads to outliers
Blunder (gross error)
Type of systematic error that is caused by non-ideal instrumental behavior
Instrumental error
Type of systematic error that arises from non-ideal chemical or physical behavior of analytical system
Method error
Type of systematic error that arises from the system itself, hence, the most difficult to deal with.
Personal errors
Test for outliers in place of the Q-test
Grubbs test
A simple, widely used statistical test for deciding whether a suspected result should be retained or rejected
Dixon’s Q-test
Refers to the range of values within which the true mean is expected to lie with a certain probability
Confidence interval
Boundaries of confidence level
Confidence Limits
Probability that the true mean lies within the certain interval
Confidence level
Probability that the result is outside the confidence interval
Significance level
The smallest concentration or absolute amount of analyte that has a signal significantly larger than the signal from a suitable blank
Detection limit
Ability to report the analyte with confidence in it’s concentration.
Limit of quantitation
Done by the use of standards that can be prepared from purified reagents or standardized by classical quantitative methods
Calibration
These are solutions containing known amounts of analyte are prepared separately from the samples. A calibration technique that can analyze series of samples using one calibration curve.
External standards
Plot of the instrument response versus known analyte concentration
Calibration or standard curve
These are used to create raw instrument responses
Blank
There are two types of blanks. A ____ contains the same solvent in which the sample is dissolved, while ____ contains the solvent plus all the reagents used in sample preparation.
Solvent blank, reagent blank
It refers to the reference species different to the analyte, but is chemically and physically similar to analyte. It is added to all samples and standards containing the analyte.
Internal standard.
In this type of calibration technique, a known amount of a standard solution of the analyte is added to one portion of the sample. Can be performed with or without dilution
Single standard addition
T-test performed to compare the mean values of the large population and the small sample take from the population
One-sample t-test
T-test performed to compare the mean values of two independent samples.
Two-sample t-test
T-test performed to compare the mean values of two independent samples.
Two-sample t-test
T-test used to compare the mean values of samples taken at two different times.
Paired sample t-test
It determines the relationship between the analytical response (signal) and the analyte concentration.
Standardization
Single point standardization leads to determinate errors. Therefore multiple point standardization should be done, which must include _____ standards.
At least three
To improve the reliability and to obtain information about the variability of the results _____ is carried out through an analytical procedure in exactly the same way.
Replicates
To improve the reliability and to obtain information about the variability of the results _____ is carried out through an analytical procedure in exactly the same way.
Replicates
