Important Terms in AnaChem Flashcards
The difference between measured or inferred value and the actual value of a quantity
ABSOLUTE ERROR
How close a given set of measurements (observations or readings) are to their true value
ACCURACY
Portion of a solution subjected to analysis
ALIQUOT
Component of interest in the sample
ANALYTE
Extremely accurate laboratory balance created to precisely measure the mass of an object
ANALYTICAL BALANCE
The science of inventing and applying the concepts, principles, and strategies for measuring the characteristics of chemical system and species
ANALYTICAL CHEMISTRY
If the reagent also meets the requirements of the American Chemical Society Committee on Analytical Reagents: Chemicals suitable for laboratory and general use.
ANALYTICAL REAGENT GRADE CHEMICALS
Defined as the estimate of the systematic error: the difference between the average of measurements made on the same object and its true value
BIAS
A sample that contains all the components of the matrix except the analyte
BLANK
The process of configuring an instrument to provide a result for a sample within an acceptable range
CALIBRATION
A process for the separation of mixtures of immiscible liquids or of a liquid and a solid mixture such as a suspension
DECANTATION
Sealable enclosures containing used for preserving moisture-sensitive items
DESICCATOR
The range of concentrations an instrument can read, from the minimum to the maximum detectable
DYNAMIC RANGE
Known data from a calibration standard and unknown data from the sample are combined to generate a quantitative report
EXTERNAL STANDARD METHOD
Involves the comparison of the instrument responses from the target compounds in the sample to the responses of reference standards added to the sample or sample extract before injection
INTERNAL STANDARD METHOD
Are errors other than random errors or systematic errors. They are often large and, by definition, unpredictable
GROSS ERRORS
The lowest concentration that can be measured (detected) with statistical significance by means of a given analytical procedure
LIMIT OF DETECTION
The lowest analyte concentration that can be quantitatively detected with a stated accuracy and precision
LIMIT OF QUANTIFICATION
The measurement range over which we can be confident of a good measurement within the tolerances of the standard
LINEAR RANGE
A mathematical technique for fitting an equation, such as that for a straight line, to experiment data
LINEAR REGRESSION
Collection of all the components in the sample
MATRIX
The sum of a group of measurements divided by the number of measurements; the average
MEAN
Used to measure and dispense specific volumes of liquids
MEASURING PIPETTE
Mohr Pipette
The middle value of a set of numbers
MEDIAN
The curve in the upper surface of a liquid close to the surface of the container or another object, produced by surface tension
MENISCUS
Detailed set of instructions for a particular analysis using a specified technique
METHOD
A common laboratory instrument used to measure small amounts of liquids with a volume range between 1 and 1000µl
MICROPIPETTE
The value that appears most often in a set of data values
MODE
A document that contains information on the potential hazards (health, fire, reactivity and environmental) and how to work safely with the chemical product
MATERIAL SAFETY DATA SHEET (MSDS)
A data point that differs significantly from other observations
OUTLIER
The change in the apparent position of an object when viewed from different points
PARALLAX
Refers to how close measurements of the same item are to each other
PRECISION
Analytical reagent of exceptional purity that is specifically manufactured for standardizing volumetric solutions and preparing reference standards
PRIMARY STANDARD GRADE CHEMICALS
The National Institute of Standards and Technology is an excellent source
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
Arise when a system of measurement is extended to its maximum sensitivity. It is caused by uncontrollable variable
RANDOM ERROR
High purity chemicals for which no established specifications exist. Are often solutions or dilution of ACS Reagent materials. Suitable for commercial, industrial, and educational application
REAGENT GRADE CHEMICALS
The ratio of the absolute error of a measurement to the measurement being taken
RELATIVE ERROR
Samples of about the same size that are carried through an analysis in exactly the same way.
REPLICATES
Process of collecting a small amount of a material whose composition represents the bulk of the materials being sampled
SAMPLING
The capacity of an analytical process to produce signals which depend almost exclusively on the target analyte(s) present in the sample.
SELECTIVITY
Ability to detect very low concentrations of a given substance in a biological specimen
SENSITIVITY
An experiment measurement that is proportional to the analyte concentration
SIGNAL
Chemicals that have been prepared for specific applications. This includes HPLC grade and spectrophotometry grade reagents
SPECIAL PURPOSE REAGENT CHEMICALS
The assay’s ability to detect the intended target
SPECIFICITY
A measure of imprecision. It indicates the variability or dispersion around the mean; roughly the average distance of data from the mean
STANDARD DEVIATION
Substances that are tested to be homogenous and have fixed values of its concentrations
STANDARD REFERENCE MATERIAL
A consistent or proportional difference between the observed and true values of something
SYSTEMATIC ERROR
Allows for you to account for only the weight of the substance being measured and not the vessel it’s being measured in
TARE
Chemicals that do not have established standards for purity levels or for products with <90%
TECHNICAL GRADE
Chemical or physico-chemical processes that provide the basis for analytical measurements
TECHNIQUES
Disposable plastic pipets used to transfer small volumes of liquids
TRANSFERRING PIPETTE
Process of verifying that a procedure yields acceptable results
VALIDATION
