# analytical 1

 The flashcards below were created by user frogginma2003 on FreezingBlue Flashcards. Define Selectivity. Selectivity is the ability to distinguish diferent components of a sample. Define Sensitivity. Sensitivity is the ability of an instrument to descriminate between small difference in [analyte]. What is Analytical Sensitivity? Slope/Standard deviation, defined from concentration. What are the 2 factors of sensitivity? 1) precision2) Slope of Calibration Curve Define Linearity. Linearity is in reference to the plots of a calibration curve to be one dimensional in respect to eachother with a high r^2 value close to 1. Define Range. Range is the area of variation in the upper and lower limits of the detection limit. What are the two kinds of ranges concerning the sensitivity of an instrument. When discussing the sensitvity of an instrument the two things to be considered are: Limit of Detection: Limit of quantification: Define Detection Limit i.e. Limit of dection. The limit of dection is the minimum amount of analyte that can be detected by a method @ a known confidence level. Define the limit of quantification. The limit of quantification is the smallest amount that the researcher can measure with reasonable accuracy with that instrument. What is the minimal extingguishable signal of an instrument? The minimal extinguishable signal of an instrament is determined by This is also known as calculating the figures of Marrit (FOM) What is the Nernst Equation? Define polarization. Polarization is the deviation of electric potential from the predicted value of the nernst equation. Attributed to 2 things:1. concentration polarization2. kinetic polarization What is Kinetic Energy? The over potential required to overcome the activation energy grams of a solid reacted on working electrode? moles reacted = What is the basic set up for a 3-electrode system? Working electrode: where rxn of interest occursAuxillary electrode: Completes circuit w/o adding additional elecronsReference electrode: measures potential directly at the working electrode Discribe strengths and weaknesses of the voltammerty technique: linear-sweep Strengths:fast Weaknesses:charging currentcan only distinguish peaks of 0.02 V apartsensitivity of 10^-4 Discribe strengths and weaknesses of the voltammerty technique: Differential pulse polargraphy Strengths:Peaks are more easily distinguishedenables the ability to distinguish peaks from 0.04 V from eachotherSensivity of 10^-7 to 10^-9 Weaknesses: Discribe strengths and weaknesses of the voltammerty technique: square wave voltammetry Strengths: 1)most effective excitation signal2) Very fast 10ms to yield data3) Same sensitivity as DPP (10^-7 to 10^-9)4) high [ ] of analyte at surface Discribe strengths and weaknesses of the voltammerty technique: Cyclic Voltammetry strengths: 1) Mostly qualitative, can be quantitative2) studies redox reactions and intermediate Weaknesses: 1) not as sensitivity as pulse methods Discribe strengths and weaknesses of the voltammerty technique: Stripping analysis Strengths: 1) great for small amounts of sample 2) Sensitivity of ^-6 to 10^-9 define frequency the number of oscillations of the electric field vector per unit time units: 1/p define velocity and units The velocity of a wave is the length the wave travels over time. This value is known as the speed of light, 3.0x10^8 m/s or 3.0x10^10 cm/s Define wavelength The linear distance between successive maxima or minima of a waves Units: cm s^-1 define wave number Wave number is defined as the number of waves per centimeter and is equal to Units: cm^-1 what is plank's constant and the equation to calculate energy in joules Plank's Constant 6.63x10^-34 define Emission spectroscopy Emission spectroscopy is the excitation by heat or a chemical rxn (chemiluminescence) to monitor wavelengths of light that is emitted. Define: Photoluminescence spectroscopy excitation by electromagnetic radiation, 2 types 1) fluorescence2) phosphorescence define fluorescence emission occurring fro s1 to s0, 10^-4 sec to 10^-8 define phosphorescence emission occurring from T1 to S0 between states of different mutiplicity define absorbance pass light through a sample and measure absorbance as a funcition of wavelength What are Beers law's limitations? Beers Law's limitations are: 1) only work ok dilute samples2) If particles are close, they will affect eatchothers charge distrucbution.3) if close, it will aslo affect the spectrum and linearity4)can get complexs and ppt that affect spectrum (chemical deviations)5) association and dissociation rxns with solvents or other molecules in matrix6) Instrument deviation, quality of monochrometer Authorfrogginma2003 ID134777 Card Setanalytical 1 Descriptionanalytical test 1 Updated2012-02-13T17:17:31Z Show Answers