Inorganic Nonmetallic Constituents Procedures

Key vocabulary terms and technical definitions for the examination of inorganic nonmetallic constituents in water and wastewater based on Standard Methods.

Proficiency Testing (PT)

A regular program (ideally semi-annual) of performance evaluation studies used to ensure analytical confidence and find causes for unsuccessful test protocols.

Method Detection Level (MDL)

The determination of the sensitivity of a test procedure, which is an essential quality control measurement for reported analytical results.

Eluent

A solution, such as a sodium bicarbonate-sodium carbonate mixture, used in ion chromatography as a stream into which the water sample is injected.

Suppressor

A device in ion chromatography, such as a hollow fiber or micromembrane cation exchanger, that converts eluent and separated anions into their acid forms to enhance conductivity measurement.

Water Dip

A negative contribution in an ion chromatogram corresponding to the elution of water, which can interfere with the quantitation of fluoride ($F^-$) at low concentrations.

Segmented Flow Analysis (SFA)

An automated method where air bubbles are used to segment the flow, reducing sample and reagent consumption and improving analytical precision through precise timing.

Bubble-Gating

A technique in segmented flow analysis that uses analog or digital processing to remove the signal distortion caused by gas bubbles without physically removing them.

Curve Regeneration

Real-time analog or digital data reconstruction techniques used in $SFA$ to remove the effect of pooling at flow-cell debubblers or other unsegmented zones.

Flow Injection Analysis (FIA)

An automated method of introducing a precisely measured portion of liquid sample into a continuously flowing carrier stream, forming an asymmetric Gaussian gradient.

Electroosmotic Flow Modifier (OFM)

A reagent, such as tetradecyltrimethyl ammonium bromide ($TTAB$), used in capillary ion electrophoresis to fill the silica capillary and aid in anion separation.

Borism

A clinical syndrome that results from the protracted ingestion of large amounts of boron, which can affect the central nervous system.

Rosocyanine

A red-colored product formed when a water sample containing boron is acidified and evaporated in the presence of curcumin.

Molecular $HCN$

The highly toxic form of cyanide predominating in natural waters with a $pH$ lower than the $pKa$ of approximately $9.2$.

Amenable to Chlorination

Cyanide species, including free cyanide and potentially dissociable complex cyanides, that are destroyed under rigorous alkaline chlorination conditions.

Weak Acid Dissociable Cyanide

A measurement of free and potentially dissociable cyanides based on a distillation procedure where the sample is slightly acidified to $pH$ between $4.5$ and $6.0$.

Cyanogen Chloride ($CNCl$)

A highly toxic gas formed as the first reaction product when cyanide compounds are chlorinated; it is used in colorimetric tests with pyridine-barbituric acid.

Free Chlorine

Chlorine in water consisting of aqueous molecular chlorine ($Cl_2$), hypochlorous acid ($HOCl$), and hypochlorite ion ($OCl^-$).

Combined Chlorine

The product of the reaction between free chlorine and ammonia or other nitrogenous compounds, consisting of monochloramine, dichloramine, and nitrogen trichloride.

DPD

$N,N$-diethyl-$p$-phenylenediamine, an indicator used in ferrous titrimetric and colorimetric methods to differentiate chlorine species.

FACTS

Free Available Chlorine Test with Syringaldazine; a procedure developed specifically for free chlorine that is unaffected by monochloramine, dichloramine, or oxidized manganese.