Page 4: Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Chlorite and Chlorate

Chlorite and chlorate in drinking water^{Footnote 1}

Appendix A: Analytical methods for chlorite and chlorate in drinking water

Analytical methods for chlorite and chlorate in drinking water
Methodology	Reference method^{Table 1 Footnote 1}	MDL^{Table 1 Footnote 2} (μg/L)	PQL^{Table 1 Footnote 3} (μg/L)	Interferences	Comments	References
Table 1 Footnotes Table 1 Footnote 1 Asterisk (*) indicates U.S. EPA proposed methods. Return to footnote 1 referrer Table 1 Footnote 2 Method detection limit: a measure of a method's sensitivity, defined as the minimum concentration of a substance that can be reported with 99% confidence that the analyte concentration is greater than zero (U.S. EPA, 1995). Return to footnote 2 referrer Table 1 Footnote 3 Practical quantitation limit: the lowest concentration of an analyte that can be reliably measured within specified limits of precision and accuracy during routine laboratory operating conditions. A PQL may be determined either through the use of interlaboratory study data or, in the absence of information, through the use of a multiplier of 5-10 times the MDL (U.S. EPA, 2003a). Return to footnote 3 referrer
Amperometric	Standard Method 4500-ClO2-E	100 (ClO₂^-)	500 (ClO₂^-)	Manganese, copper, nitrate and other oxidants	Identify Cl₂, ClO₂, ClO₂^- and ClO₃^-; adequate for utility use in daily testing	APHA et al., 1998
Ion chromatograph/ conductivity	U.S. EPA Method 300.0 (1993B Revision 2.2)	10 (ClO₂^-) 3 (ClO₃^-)	50 (ClO₂^-) 15 (ClO₃^-)	Chloramine, ClO₂	Good sensitivity, high expertise required; cannot determine Cl₂ or ClO₂	U.S. EPA, 1999b
Ion chromatograph/ conductivity	U.S. EPA Method 300.1 (1997E Revision 1.0)	0.45 (ClO₂^-) 0.78 (ClO₃^-)	2.2 (ClO₂^-) 3.9 (ClO₃^-)	Chloramine, ClO₂	Good sensitivity, high expertise required; cannot determine Cl₂ or ClO₂	U.S. EPA, 1998
Ion chromatograph/ conductivity and ultraviolet/visible detectors	U.S. EPA Method 317.0, Revision 2.0*	1.6 (ClO₂^-) 0.24 (BrO₃^-)	8.0 (ClO₂^-) 1.2 (BrO₃^-)	ClO₂	Similar to 300.1; post-column reactor with o-dianisidine dihydrochloride; UV/VIS detector specifically targetting bromate	U.S. EPA, 2001a
Ion chromatograph/ conductivity and ultraviolet/visible detectors	U.S. EPA Method 326.0, Revision 1.0*	1.6 (ClO₂^-) 0.17 (BrO₃^-)	8.0 (ClO₂^-) 0.9 BrO₃^-)	ClO₂	Similar to 300.1; post-addition of KI and Mo(VI); UV/VIS detector specifically targetting bromate	U.S. EPA, 2002
Ultraviolet/visible spectrophotometric Lissamine Green B	U.S. EPA Method 327.0, Revision 1.0*	78 (ClO₂) 78 (ClO₂^-)	100 (ClO₂) 100 (ClO₂^-)	Free Cl₂ (eliminated with glycine) and ClO₂ (removed by sparging with inert gas)	Adequate for utility use in conjunction with daily monitoring; two-step procedure	U.S. EPA, 2003b
Flow injection analysis -- iodometric	Flow injection analysis	130 (ClO₂) 10 (ClO₂^-) 20 (ClO₃^-)	650 (ClO₂) 50 (ClO₂^-) 100 (ClO₃^-)	Specific interferences are removed using masking agents	Identify ClO₂, ClO₂^- and ClO₃ ^-; may be automated and on-line	Novatek, 1991

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Date modified:: 2014-12-12