ANACHEM

• Error in measurements:

  • Errors are caused by faulty calibrations or standardizations, or by random variations and uncertainties in results
  • Frequent calibrations, standardizations, and analyses of known samples can be used to lessen all but the random errors and uncertainties

  
• Meanings of Error:

  • Error refers to the difference between a measured value and the “true” or “known” value
  • Error often denotes the estimated uncertainty in a measurement or experiment
• Characteristics of Analytical Methods:

  • Accuracy: the degree to which an experimental result approaches the true or accepted answer
  • Precision: the reproducibility of results, related to random error
• Response in analytical methods:

  • Describes how the result or signal of a method varies with the amount of compound or property being measured
  • Sensitivity: ability to discriminate between small differences in analyte concentration, determined by the slope and reproducibility of the calibration curve
• Selectivity in analytical methods:

  • Degree to which the method is free from interference by other species in the sample
  • No method is totally free from interference from other species
• Limits of Detection:

  • Minimum/maximum concentration or mass of analyte that can be detected at a known confidence level
  • Signal-to-noise Ratio (S/N): noise is random variation in signal or background, signal is the net response recorded by a method for a sample
• Dynamic Range in analytical methods:

  • Linear region of calibration curve where the lower limit is ten times the standard deviation of the blank
  • LOQ (limit of quantitation) and LOL (limit of linearity) are important parameters
• Calibration of Glassware:

  • Calibration is the method of assigning a price to a tool response
  • Calibration ensures that a scientific method or device will produce accurate results
• A random error is depicted as a bell-shaped curve centered around the mean, while a systematic error is shown as a curve shifted away from the mean

  
• A calibration curve for sulfate is used in chemistry to determine the concentration of sulfate ions in a solution

  
• Volumetric burettes convey measured volumes of fluid, while piston burettes can be comparative to syringes, offering precision in fluid measurement
• Pipettes are laboratory devices used in chemistry, biology, and medicine to move a measured amount of liquid, available in various designs for different functions and levels of accuracy
• Volumetric flasks are laboratory flasks calibrated to contain a specific volume at a certain temperature, used for specific dilutions and preparation of standard solutions
• Graduated cylinders are used to determine the volume of a liquid, with each marked line representing a measured amount, more accurate than flasks and beakers but not for volumetric analysis
• Thermometers measure temperature or temperature gradients, widely used in various fields like science, industry, meteorology, and medical research
• Syringes are reciprocating pumps used to absorb and expel liquid or gas, commonly used in medical treatment for injections, infusions, and compound application
• Beakers are cylindrical containers with a flat bottom, often used in laboratories for mixing and heating liquids, distinguishable from flasks by their straight sides
• Erlenmeyer flasks, test tubes, droppers, and Petri dishes are common non-volumetric flasks used in laboratories for various purposes like titration, culturing, and chemical dispensing
• Precautions for using glassware in laboratories include inspecting for damage, handling carefully, knowing capacity limits, using caution with fragile glassware like rods and tubes, labeling glassware, and maintaining cleanliness and sterilization
• Attachment is a strong reciprocal emotional bond between an infant and a primary caregiver

  
• Schaffer and Emerson's 1964 study on attachment:

  • Aim: identify stages of attachment / find a pattern in the development of an attachment between infants and parents
  • Participants: 60 babies from Glasgow
  • Procedure: analysed interactions between infants and carers
  • Findings: babies of parents/carers with 'sensitive responsiveness' were more likely to have formed an attachment
• Freud's superego is the moral component of the psyche, representing internalized societal values and standards
• Gravimetric Method:

  • Isolates the constituent to be determined as an element or a compound of definite composition in a sample and weighs it in some pure form
  • Isolation methods include precipitating the sought substances in an insoluble form, depositing a pure metal by electrolysis, or converting the substance to a gas absorbed in a suitable reagent

  
• Volumetric Analysis or Titrimetric Analysis:

  • Involves reacting the constituent to be determined with another reagent that will give a definite and complete chemical reaction
  • Types include Acidimetry, Double Indicator Method, and Oxidation-Reduction Method (PIID) with subtypes like Permanganimetry, Iodimetry, Iodometry, and Dichromate and Ceric Process
• Instrumental Methods in Analytical Chemistry:

  • Use instruments as principal measuring devices other than those in conventional gravimetric and volumetric determination
  • Include Electrometric Methods like Electrolytic Methods and Potentiometric Method, and Optical Methods like Colorimetric Method and Spectrophotometric Methods
• Steps in Chemical Analysis:

  • Planning methods carefully for accurate and precise results
  • Sampling to obtain a laboratory-sized sample representing the average composition of the whole bulk of the sample, using methods like sawing, milling, and shaking for solid, liquid, and gas samples respectively
• Random error is intangible and the origin is not possibly determined, while systematic error is more tangible and its magnitude can be determined or approximated

  
• Types of systematic errors:

  • Personal error: due to carelessness of the observer
  • Method error: inherent in the method itself
  • Instrumental error: due to the instrument itself
  • Cross Careless Error: due to mistakes that are not repeated in similar determinations
• Types of reagents:

  • Technical or Commercial Grade Reagent
  • USP Grade and NF grade
  • C.P. and Analyzed Grade
  • Primary Standard
• Types of high pure grade reagents:

  • Reagent Grade of Analytical Grade
  • Chemical Pure Grade
• Types of water used in experiments:

  • Type 1 Reagent Water: for procedures requiring maximum water purity
  • Type II Reagent Water: for most clinical laboratory determinations
• Types of glassware:

  • Graduated Cylinder: used where less accuracy is needed
  • Burette: used for titration
  • Volumetric Flasks: used for preparation of standard solutions
  • Beaker: used for mixing and reagent preparation
  • Erlenmeyer Flask: used for preparing reagents and titration purposes
  • Test Tubes: used as a chemical reaction medium
• Rules for significant figures:

  • All non-zeros are significant
  • Zeros between two non-zeros are significant
  • Leading zeros are not significant
  • Trailing zeros to the right of the decimal are significant
  • Trailing zeros in a whole number with the decimal shown are significant
  • Trailing zeros in a whole number with no decimal shown are not significant
  • Exact numbers have an infinite number of significant figures
  • For a number in scientific notation, all digits comprising N are significant by the first 6 rules; "10" and "x" are not significant