Gravimetric Analysis and Professionalism Guidelines

Flashcards covering the definitions, mechanisms, and specific protocols for Gravimetric Analysis methods, precipitation types, and impurity management, along with clinical chemistry reference range data.

Gravimetric Methods

Quantitative methods based on determining the mass of a pure compound to which the analyte is chemically related.

Precipitation Gravimetry

A technique where the analyte is separated from a solution as a precipitate and converted to a compound of known composition that can be weighed.

Volatilization Gravimetry

A technique where the analyte is separated from other constituents of a sample by converting it to a gas of known chemical composition that can be weighed.

Electrogravimetry

A method where the passage of electric current causes the deposition of metal upon an already weighed inert electrode.

Colloidal Suspensions

Suspensions consisting of tiny particles with diameters ranging from $10^{-7}$ to $10^{-4} ext{ cm}$ that are very difficult to filter.

Crystalline Suspensions

Suspensions where particles normally settle out spontaneously and possess diameters greater than tenths of a millimeter.

Nucleation

A process where individual ions, atoms, or molecules coalesce to form stable solid nuclei.

Particle Growth

A process where ions, atoms, or molecules are added to an existing nucleus to form larger particles.

Supersaturated Solution

An unstable solution that contains a higher solute concentration ($Q$) than a saturated solution ($S$).

Relative Supersaturation (RSS)

An expression defined by the Von Weimarn equation: RSS = rac{Q - S}{S}.

Co-precipitation

A process where impurities are precipitated along with the desired precipitate, such as surface adsorption, occlusion, inclusion, or mechanical entrapment.

Surface Adsorption

A source of contamination where impurities are chemically or physically held on the surface of precipitates; it is the major source of contamination in coagulated colloids.

Digestion

A process involving a waiting time, often at higher temperatures, to expel water from solids or ensure occluded material is exposed to the supernatant solution for better purity.

Reprecipitation

A purification procedure where a filtered solid is redissolved and then precipitated again to reduce the concentration of contaminants.

Inclusion (Mixed-Crystal Formation)

A type of coprecipitation where a contaminant ion replaces an ion in the crystal lattice of a precipitate.

Occlusion

A type of coprecipitation where foreign ions in the counter-ion layer are physically trapped within a precipitate during rapid formation.

Mechanical Entrapment

A process where crystals lie close together during growth and physically trap a pocket of the solution.

Solubility Exception: PMS

A mnemonic for specific exceptions to solubility rules: $Pb^{2+}$ (lead), $Hg_2^{2+}$ (mercury), and $Ag^+$ (silver).

Solubility Exception: Castro Bear

A mnemonic for specific exceptions to solubility rules involving $Ca^{2+}$, $Sr^{2+}$, and $Ba^{2+}$.

Bilirubin SI Unit Conversion

The factor used to obtain the SI unit ($ext{μmol/L}$) by multiplying the value in $ext{mg/dL}$ by $17.10$.