analytical topic 1 Flashcards
Definitions Errors Samples and Standards Standardization and Calibration Curves
What are ‘Modern’ or ‘Instrumental’ methods in Analytical Chemistry?
Methods based on measuring the interaction of matter with light, heat, electric/magnetic fields.
What is Qualitative Analysis?
Obtaining information about the identity of components present in a sample.
What is Quantitative Analysis?
Estimating how much of one or more components are present in a sample.
What is the difference between specific and selective tests in Qualitative Analysis?
A specific test responds to only one component, while a selective test exhibits preference for one component but responds to others as well.
What is required for a Quantitative Analysis?
Knowledge of the identity of components in a sample, obtained from history or qualitative analysis.
What is an analyte?
A target component in a sample that is being analyzed.
What is the matrix in a sample?
All other combined components that are not the analyte.
What is a signal in Analytical Chemistry?
The measured response obtained from the analysis of a sample.
What is a technique in Analytical Chemistry?
The principle involved in the analysis, which could be chemical, physical, or a combination.
What is an analytical method?
The application of one or more techniques for the analysis of a sample to determine a specific analyte.
What is a procedure in Analytical Chemistry?
A set of instructions that describe how to apply the method for analysis.
What is a total analysis technique?
A technique that measures all of the analyte in a sample.
What is a concentration technique?
A technique that measures the relative amount of analyte in a sample.
What is concentration in Analytical Chemistry?
An expression of the proportion of the sample that is due to a particular analyte.
What are typical units of concentration?
M, mM, %w/v, %w/w, ppt, ppm, ppb.
What factors should be considered when selecting the best method in Analytical Chemistry?
Accuracy, precision, sensitivity, and selectivity.
What is the purpose of calibration in Analytical Chemistry?
To ensure that all equipment used in the method is working properly.
What is a primary standard?
A substance of known molecular formula and purity that is stable when stored and during use.
What is a secondary standard?
A substance that can be used in a method after establishing its purity using a primary standard.
What is the importance of preparation of standards?
To avoid excessive light, temperature, and humidity that can alter the chemical structure during storage and use.
What is accuracy in measurements?
An indication of how close the measured value is to the true value.
What is precision in measurements?
An indication of the spread of repeat measurements.
What are determinate or systematic errors?
Errors that result from a bias in a series of measurements.
What are indeterminate or random errors?
Errors that result from accidental events or background noise.
What is standardization in Analytical Chemistry?
The relationship between the response signal for a method and the concentration of an analyte.
What is a calibration curve?
A graph that represents the relationship between the response signal for a series of external standards with different concentrations of analyte.
What are matrix effects?
Contaminants in a sample that alter the way the analyte responds to the detection system.
What is the purpose of using internal standards?
To minimize handling errors by adding a known amount of a standard to all external standards and samples.
What is standard addition?
A method where the change in the response signal is measured when the concentration of analyte is spiked with additional analyte standard.
What are multiple additions in standard addition?
A method that enables a Standard Addition curve to be constructed by measuring the response signal changes with added spikes of standard.
What is the summary of learning outcomes in Analytical Chemistry?
Appreciate the wide applicability of chemical analysis, understand the difference between qualitative and quantitative analysis, and be familiar with different methods of standardization.
