Analytical Chemistry Flashcards
processes the provides basis for analytical measurement
Technique
a detailed set of instructions for a particular analysis using a specified technique
Method
A set of written instructions on how to apply a method to a particular sample
Procedure
Set of written guidelines for the analysis of a sample specified by an agency
Protocol
Component of interest in sample
Analyte
What are the instrumental methods of the following:
A. Absorption of radiation
B. Electrical Potential
C. Electrical Charge
D. Electrical current
E. Mass-to-Charge ratio
F. Rate of reaction
G. Thermal characteristics
H. Radioactivity
A. Spectroscopy
B. Potentiometry
C. Coulometry
D. Amperometry, Polarography
E. Mass Spectrometry
F. Kinetic methods
G. Thermal gravimetry, DTA, DSC
H. Activation and isotope dilution methods
Collection of all the components in the sample
Matrix
Process of collecting small amount of material whose composition represents the bulk of the material being sampled
Sampling
Portion of a solution subjected to analysis
Aliquot
A sample that contains all the components except the analyte
Blank
Experimental measurement that is proportional to analyte concentration
Signal
A. Middle result in the set of data. It is not affected by extreme values.
B. Also known as arithmetic mean. It is affected by extreme values.
A. Median
B. Mean
Indicates the reproducibility (repeatability) of a measurement.
Precision
Measure of the agreement between an experimental result and an expected value
Accuracy
Type of Errors
A. Causes date to be more scattered more or less symmetrically around the mean.
B. causes the mean of set data to differ from the accepted value.
C. Are often large, and may cause a result to be either high or low.
A. Random (indeterminate) error
B. Systematic (determinate) error
C. Gross error
Simple, widely used statistical test for deciding whether a suspected result should be retained or rejected
Q-test
Recommended by the ISO and the Americal Society for Testing and Materials in place of Q-test
Grubb’s test
Measure of the method’s ability to distinguish between two samples. It is reported as a change in signal per unit change in the amount of analyte
Calibration sensitivity
IUPAC defined it as the smallest concentration or absolute amount of analyte with a signal significantly larger than the signal from a suitable blank.
Limit of Detection (Detection limit)
Smallest amount of analyte that can be measured with reasonable accuracy
Limit of Quantitation (Quantitation Limit)
_______ of an analytical method is said to be specific if its signal depends only on the analyte
Specificity
Measure of method’s freedom from interferences
Selectivity
Magnitude of the background signal divided by the standard deviation of the background signal
Signal-to-Noise ratio
_____ is the fraction of the named material present
Purity
It determines the material’s purity
Grade
Chemical grade that exceeds the purity standards set by the ACS with a purity of equal or more than 95%
ACS
Chemical grade where High purity chemicals have no established specifications
Reagent or analytical reagent
Chemical grade that meets or exceeds requirements set by the US Pharmacopeia. Acceptable for food, drug, or medicinal use.
USP
Chemical grade that meets or exceeds the requirements set by the National Formulary. Acceptable for food, drug, or medicinal use.
NF
Chemical grade with relatively high quality with exact levels of impurities unknown. Use for educational purposes.
Laboratory grade
Chemical grade with no established standards for purity level or for products with less than 90% purity.
Technical or Commercial
Describes whether a product or a service meets the minimum specifications set by the costumer in a timely manner.
Quality
Planned and systematic control that will give assurance of the quality of data generated in the laboratory
Quality Assurance
“assembly of all planned and systematic actions necessary to provide adequate confidence that a product, process, or service, will satisfy the given quality requirements” - ISO
Quality Assurance
Involves the confirmation that the quality management system in the laboratory is fully implemented. It is specific only to a product, process, or service.
Certification
Formal procedure carried out by the relevant authority, which confers formal recognition that a laboratory is competent to carry out certain tasks.
Accreditation
Most general and globally recognized standards employed for testing and calibration laboratories
ISO/IEC 17025:2005
Promotes the adoption of a process approach when developing, implementing, and improving the effectiveness of a Quality Management System
ISO 9001
The quality standard that covers the preparation of samples derived from the human body
ISO 15189
Standard protocol required for all analytical laboratories which are concerned in the overall process in the laboratory…; a subsection of GMP
GLP (Good Laboratory Practices)
A standard protocol that requires all organizations manufacturing products for human consumption to be safe, pure, and effective
GMP (Good Manufacturing Practices)
Quality System standards employed in pathology labs
CPA (Clinical Pathology Accreditation)
Types of Blank
1) A sample containing all components except the analyte and is taken through all steps in the analytical procedure
2) A type of blank that is not subjected to all sample preparation procedures
3) A type of blank that has been exposed to the site of sampling. It is subject to possible sources of contamination
1) Method blank
2) Reagent Blank
3) Field Blank
TYPE OF SAMPLE
1) Samples of known compositions, having very similar matrix and analyte concentrations to the samples to be analyzed. It is also known as check samples.
2) A type of sample that provides a less formal check than QC samples. They are repeated in different batches.
3) A sample inserted into the analytical batch without the knowledge of the analyst.
1) QC Samples
2) Repeat Samples
3) Blind samples
Also known as fortification. It involves adding a known quantity of analyte to a sample to test whether the response to the sample is the same as that expected from a calibration curve.
Spike