chem

• A titration is a process where a known volume of a solution of known concentration (titrant) is added to a solution of unknown concentration (analyte) until the reaction is complete, used to calculate the concentration of the analyte

  
• Analytical Chemistry involves the analysis of chemical substances through measurement science, characterizing matter, and includes separating techniques, qualitative chemical tests, and determining the relative amounts of components in a sample
• Qualitative Analysis in Analytical Chemistry involves identifying ions, elements, or compounds in a sample, while Quantitative Analysis deals with determining the amount of constituents present within a sample, expressed in concentration
• Qualitative Methods of Analysis in Analytical Chemistry include Chemical Tests, Flame Tests, Gravimetric Method, Volumetric Method, and Instrumentation Method
• Basic Analytical Process steps:

  1. Select a Method

  2. Acquire the Sample

  3. Process the Sample

  4. Eliminate Interferences

  5. Calibrate and Measure Concentration

  6. Calculate Results

  7. Evaluate Results by Estimating Reliability
• Analytical Chemistry is applicable in various fields like Medicine, Industry, Environment, Food, Forensic, Biochemistry, and Pharmaceutical Science
• A titration is a process where a known volume of a solution of known concentration (the titrant) is added to a solution of unknown concentration (the analyte) until the reaction between the two solutions is complete

  
• The volume of titrant used in a titration is then used to calculate the concentration of the analyte

  
• Errors in the laboratory:

  • Analytical results are used in various fields like disease diagnosis, pollution assessment, crime solving, and industrial quality control
  • Errors in results can have serious personal and societal effects
  • Not all errors in the laboratory are mistakes
• Types of error:

  • Determinate/Systematic Error:
  • Can be determined or eliminated, affecting the accuracy of results
  • Systematic error is predictable and either constant or proportional to the measurement
  • Typical causes include observational error, imperfect instrument calibration, and environmental interference
• Systematic error causes bias in measurement results:

  • Bias is the deviation from the target value
  • Measures the systematic error associated with an analysis
  • Systematic errors have a definite value, an assignable cause, and are of the same magnitude for replicate measurements made in the same way
• Systematic error can be minimized by:

  • Routinely calibrating equipment
  • Using controls in experiments
  • Warming up instruments prior to taking readings
  • Comparing values against standards
• Instrumental Errors:

  • Caused by non-ideal instrument behavior, faulty calibrations, or use under inappropriate conditions
• Method Errors:

  • Arise from non-ideal chemical or physical behavior of analytical systems
• Personal Errors:

  • Result from the carelessness, inattention, or personal limitations of the experimenter
• Indeterminate/Random Error:

  • Errors that cannot be determined or controlled, affecting precision
  • Random errors are the cumulative effect of many small, uncontrollable variables and personal judgments that lead to uncertainty in a measured value
• Random error affects the last significant digit of a measurement and is caused by limitations of instruments, environmental factors, and slight variations in procedure
• Assessment of reliability of results:

  • Evaluate the error and its source
  • Perform the same procedure from known values
  • Compare with standard values
  • Calibration of equipment
  • Statistical treatments
• Basic statistical treatments:

  • Three to five portions (replicates) of a sample are usually carried through an entire analytical procedure
  • Mean: sum of numbers divided by the number of measurements
  • Median: the middle value in a set of data arranged in numerical order
• Accuracy and precision in analytical measurements:

  • Accuracy describes the nearness of an experimental value or a mean to the true value
  • Precision refers to the agreement between values in a set of data
• Examples:

  • True mass of the wire is 2.000 g
  • Student B's results are more precise than those of Student A
• The mean is a measure of the central tendency of a dataset, calculated by adding up all values and dividing by the number of values; it is not affected by outliers

  
• Measurement of Precision:

  • Higher standard deviation / RSD / coefficient of variance / variance indicates less precision
  • Sample Standard Deviation (s) describes the spread of data around the mean data point for a set of replicate measurements
• Significant Figures:

  • All nonzero digits in a measurement are significant
  • Interior zeros (zeros between nonzero numbers) are significant
  • Leading zeros are significant if there is a decimal point present in the number
  • In numerical computations:
  • Addition or subtraction: result has the same number of decimal places as the measurement with the lowest number
  • Multiplication or division: result has the same number of significant figures as the measurement with the lowest number
• Analytical Chemistry is a branch of chemistry involved with the analysis of chemical substances through measurement science
• Analytical Chemistry involves:

  • Separating techniques (reduction of samples, filtration, extraction)
  • Qualitative chemical tests for identification
  • Quantitative analysis to determine the relative amounts of components in a sample
• Qualitative Analysis in Analytical Chemistry involves identifying ions, elements, or compounds in a sample of interest
• Quantitative Analysis in Analytical Chemistry deals with determining the amount of one or more constituents present within a sample, expressed in concentration
• Basic Analytical Process:

  1. Select a Method considering accuracy, sample complexity, and number of components

  2. Acquire the Sample representing the entire bulk material

  3. Process the Sample by preparing, defining replicate samples, and performing physical or chemical changes

  4. Eliminate Interferences by selecting reagents or methods to minimize errors

  5. Calibrate and Measure Property X

  6. Calculate Results based on raw data, instrument characteristics, and stoichiometry

  7. Evaluate Results by estimating reliability
• A titration is a process where a known volume of a solution of known concentration (the titrant) is added to a solution of unknown concentration (the analyte) until the reaction between the two solutions is complete

  
• The volume of titrant used in a titration is then used to calculate the concentration of the analyte

  
• The Triversa NanoMate is a liquid chromatography system used to separate and analyze complex mixtures of molecules, including in proteomics, metabolomics, and drug discovery

  
• It is a high-performance liquid chromatography (HPLC) system that uses a nano-scale column to achieve high resolution and sensitivity

  
• The mean, a measure of central tendency, is calculated by adding up all values in a dataset and dividing by the number of values

  
• The standard deviation of a sample is a measure of the amount of variation or dispersion of a set of values

  
• Errors in the laboratory can be determinate/systematic or indeterminate/random
• Systematic errors can be minimized by routinely calibrating equipment, using controls in experiments, warming up instruments prior to taking readings, and comparing values against standards
• Random errors are the cumulative effect of many small, uncontrollable variables and personal judgments that lead to uncertainty in a measured value
• Random errors affect the last significant digit of a measurement and are caused by limitations of instruments, environmental factors, and slight variations in procedure
• The mean is the sum of numbers divided by the number of measurements, while the median is the middle value in a set of data arranged in numerical order