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Water Analysis Important for Disinfection Safety Zoe A. Grosser Ph.D. and Kenneth Neubauer Ph.D.
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ater for public consumption must be purified prior to their portion of the analysis. Bridging the gap is key to creating dis-tribution or bottling. Chlorine is commonly used the best method for analysis. For example, chromatographers for disinfection, but may create hazardous disinfecmust consider minimizing the use of glass, organic solvents and tion by-products, depending on the residual organic content of the total dissolved solid content of the mobile phase. All of these the water supply. Treatment with ozone is another disinfection areas do not need to be considered for ‘normal’ HPLC analyalternative. While this method is effective, ozonolysis can also ses, but can cause problems for inorganic detection (i.e., glass is convert bromide (Br-), a natural component of many waters, dirty with respect to inorganic elements and glass components into bromate (BrO3-), a carcinogen. can therefore contaminate a sysTherefore, the need exists to meatem leading to false high results). sure bromate in drinking waters, Figure 1. Chromatogram (isocratic LC method) ICPs do not handle highly organic which means that it must be mea- of a standard containing one µg/L of bromide solvents very well under normal sured separately from other forms and bromate sample introduction conditions, of bromine. In addition, each form although modifications can be is usually present at low concenmade to accommodate samples trations. Current methods for with high organic content. Finally, measuring bromate and bromide high total dissolved solids (TDS) involve separating the brominecan deposit on various compocontaining components by liquid nents within an ICP-MS, leading chromatography (HPLC) and usto drift over time and frequent ing inductively coupled plasma maintenance. mass spectrometry (ICP-MS) as a The inorganic chemist must detector. This is the protocol stated also have proper expectations in US EPA Drinking Water Method about HPLC method develop321.8. Bromate at 10 mg/L (partsment, which is more complex and per-billion) in drinking water has been regulated in the US since 1997. The US FDA has adopted Figure 2. Overlay of 49 chromatograms (isocratic the same standard for bottled water exposed to ozonation for LC method) of a Chinese bottled water sample disinfection. Similar levels are regulated in Europe for a variobtained by consecutive injections. The average ety of water types. concentration and standard deviation for each Primary drinking water contaminants are generally measpecies is shown sured by a single technique, such as HPLC or gas chromatography for organic components and ICP-MS for inorganic components. The use of a combined technique for inorganic speciation has only recently become routine and is still rapidly advancing in developments devoted to speed and ruggedness.
Challenges in developing speciation methods Development of a speciation method requires two types of expertise. The chromatographer is best skilled for development of the separation portion of the procedure, while the inorganic analytical chemist is best suited for optimizing the detection system, in this case ICP-MS. Each area of expertise has a separate ‘language’ and knowledge of aspects that are important in AUGUST 2007
Water Conditioning & Purification
time consuming than develop- Figure 3. Chromatogram of a Thailand bottled ment of an ICP-MS method. Im- water with an isocratic HPLC separation method portant variables include the (A) and a gradient HPLC separation method (B) mobile phase composition and various column characteristics, such as packing material, particle size and length. The method development involves real chemistry and may take weeks!
Recent advances in bromate measurement
method was established. Taken together, the isocratic separation scheme can serve as a rapid screening method; those samples which contain additional bromine species can then be confirmed using the longer gradient method. It is interesting to note that not all countries regulate or enforce bromate at levels considered safe in the US. Although bottled water may contain less bacteria than tap water outside the US, it may not contain safe levels of disinfection byproducts (DBPs) such as bromate.
Since the development of US EPA Method 321.8 in 1998, advances in speciation have taken place, allowing the method to be improved for ruggedness and References speed. Figure 1 shows a chro1. Neubauer, Kenneth R., Reuter, matogram of one mg/L of broWilhad M., Perrone, Pamela A., mate, showing that even at very Grosser, Zoe A., Bromate/Bromide Spelow concentrations it can be disciation by HPLC-ICP-MS, presentation tinguished from the background at PITTCON, Orlando, Fla., March 2006. levels.1 Note that time for analysis is 2. Neubauer, Kenneth R., Reuter, less than three minutes, whereas Wilhad M., Perrone, Pamela A., Adthe Method 321.8 chromatovances in Bromine Speciation by HPLC/ graphic separation takes eight ICP-MS, Application Note 007303A_ 01, PerkinElmer Corporation, Shelton, minutes. Figure 2 shows overlaid Conn. 2006. chromatograms of a Chinese bottled water analyzed 49 times over the Table 1. Quantitative About the company course of several hours to examine the determination of bromide 6 PerkinElmer, Inc. is a global technology short-term precision, which is better than and bromate in bottled and leader focused in the following businesses: life two percent. tap water samples confirmed and analytical sciences, optoelectronics and For a few samples with asymmetrical with a gradient HPLC method fluid sciences. Combining operational excelpeaks and high bromate values, additional (All units in µg/L) lence and technology expertise with an intimethod development was done to ensure Sample BrO3– Br– mate understanding of its customers’ needs, the analyte of interest was adequately sepaAustralia — 38.1 PerkinElmer creates innovative solutions— rated from any other components that backed by unparalleled service and support— Brazil — 7.94 might mistakenly contribute to the bromate for customers in health sciences, semiconducSpain — 23.5 measurement. A gradient HPLC method, tor, aerospace and other markets whose Thailand-1 37.4 17.3 although slightly longer than the isocratic applications demand absolute precision and method developed for routine use, showed Thailand-2 76.0 — speed. The company markets in more than 125 several peaks overlapped the bromate peak Thailand-3 3.03 9.36 countries and is a component of the S&P 500 in some samples.2 Advanced interference Index. Additional information is available US-1 — 8.79 correction on the ICP-MS showed that the through www.perkin elmer.com or 1-877-PKIUS-2 — 224 additional peaks did, in fact, contain broNYSE. PerkinElmer Life and Analytical SciChina-1 20.8 7.41 mine. Their identification was not investiences at 710 Bridgeport Avenue, Shelton Conn. gated further. Figure 3 shows the China-2 16.1 11.9 06484 manufactures the Perkin Elmer Series chromatogram for a bottled water purChina-3 (Tap) — 380 200 HPLC and ELAN® DRC™ II ICP-MS, chased in Thailand showing the additional China-4 14.0 11.8 using Chromera™ software, the measuring depeak, uncovered with the gradient separavices used for this research. China-5 (Tap) — 64.6 tion method. Table 1 shows the concentrations of bromide and bromate for a variety About the corresponding author of bottled and tap water samples. The samples with suspect 6 Zoe Grosser, Ph.D. is Segment Marketing Manager, Analytical peaks or bromate concentrations above the regulatory limit were Sciences of PerkinElmer Life and Analytical Sciences. She has been confirmed with the developed gradient HPLC separation to enwith the firm for more than 20 years, having held a variety of sure that only one peak was present at the retention time exmarketing, product development and product support roles. Prior to pected for bromate. joining PerkinElmer, she was an analytical problem solver at American Cyanamid. She obtained a doctorate in analytical chemistry from Summary Northeastern University and holds a Master’s in business administraSpeciation development continues in this improvement of tion/marketing from the University of Connecticut. Grosser can be existing methodology. The separations are accomplished in less reached via email at [email protected] or telephone: (203) than three minutes and proved to be repeatable from injection 402-5320. to injection and over several days. For those waters containing additional bromine-containing species, a gradient HPLC Reprinted with permission of Water Conditioning & Purification Magazine ©2007 Water Conditioning & Purification
AUGUST 2007
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ater for public consumption must be purified prior to their portion of the analysis. Bridging the gap is key to creating dis-tribution or bottling. Chlorine is commonly used the best method for analysis. For example, chromatographers for disinfection, but may create hazardous disinfecmust consider minimizing the use of glass, organic solvents and tion by-products, depending on the residual organic content of the total dissolved solid content of the mobile phase. All of these the water supply. Treatment with ozone is another disinfection areas do not need to be considered for ‘normal’ HPLC analyalternative. While this method is effective, ozonolysis can also ses, but can cause problems for inorganic detection (i.e., glass is convert bromide (Br-), a natural component of many waters, dirty with respect to inorganic elements and glass components into bromate (BrO3-), a carcinogen. can therefore contaminate a sysTherefore, the need exists to meatem leading to false high results). sure bromate in drinking waters, Figure 1. Chromatogram (isocratic LC method) ICPs do not handle highly organic which means that it must be mea- of a standard containing one µg/L of bromide solvents very well under normal sured separately from other forms and bromate sample introduction conditions, of bromine. In addition, each form although modifications can be is usually present at low concenmade to accommodate samples trations. Current methods for with high organic content. Finally, measuring bromate and bromide high total dissolved solids (TDS) involve separating the brominecan deposit on various compocontaining components by liquid nents within an ICP-MS, leading chromatography (HPLC) and usto drift over time and frequent ing inductively coupled plasma maintenance. mass spectrometry (ICP-MS) as a The inorganic chemist must detector. This is the protocol stated also have proper expectations in US EPA Drinking Water Method about HPLC method develop321.8. Bromate at 10 mg/L (partsment, which is more complex and per-billion) in drinking water has been regulated in the US since 1997. The US FDA has adopted Figure 2. Overlay of 49 chromatograms (isocratic the same standard for bottled water exposed to ozonation for LC method) of a Chinese bottled water sample disinfection. Similar levels are regulated in Europe for a variobtained by consecutive injections. The average ety of water types. concentration and standard deviation for each Primary drinking water contaminants are generally measpecies is shown sured by a single technique, such as HPLC or gas chromatography for organic components and ICP-MS for inorganic components. The use of a combined technique for inorganic speciation has only recently become routine and is still rapidly advancing in developments devoted to speed and ruggedness.
Challenges in developing speciation methods Development of a speciation method requires two types of expertise. The chromatographer is best skilled for development of the separation portion of the procedure, while the inorganic analytical chemist is best suited for optimizing the detection system, in this case ICP-MS. Each area of expertise has a separate ‘language’ and knowledge of aspects that are important in AUGUST 2007
Water Conditioning & Purification
time consuming than develop- Figure 3. Chromatogram of a Thailand bottled ment of an ICP-MS method. Im- water with an isocratic HPLC separation method portant variables include the (A) and a gradient HPLC separation method (B) mobile phase composition and various column characteristics, such as packing material, particle size and length. The method development involves real chemistry and may take weeks!
Recent advances in bromate measurement
method was established. Taken together, the isocratic separation scheme can serve as a rapid screening method; those samples which contain additional bromine species can then be confirmed using the longer gradient method. It is interesting to note that not all countries regulate or enforce bromate at levels considered safe in the US. Although bottled water may contain less bacteria than tap water outside the US, it may not contain safe levels of disinfection byproducts (DBPs) such as bromate.
Since the development of US EPA Method 321.8 in 1998, advances in speciation have taken place, allowing the method to be improved for ruggedness and References speed. Figure 1 shows a chro1. Neubauer, Kenneth R., Reuter, matogram of one mg/L of broWilhad M., Perrone, Pamela A., mate, showing that even at very Grosser, Zoe A., Bromate/Bromide Spelow concentrations it can be disciation by HPLC-ICP-MS, presentation tinguished from the background at PITTCON, Orlando, Fla., March 2006. levels.1 Note that time for analysis is 2. Neubauer, Kenneth R., Reuter, less than three minutes, whereas Wilhad M., Perrone, Pamela A., Adthe Method 321.8 chromatovances in Bromine Speciation by HPLC/ graphic separation takes eight ICP-MS, Application Note 007303A_ 01, PerkinElmer Corporation, Shelton, minutes. Figure 2 shows overlaid Conn. 2006. chromatograms of a Chinese bottled water analyzed 49 times over the Table 1. Quantitative About the company course of several hours to examine the determination of bromide 6 PerkinElmer, Inc. is a global technology short-term precision, which is better than and bromate in bottled and leader focused in the following businesses: life two percent. tap water samples confirmed and analytical sciences, optoelectronics and For a few samples with asymmetrical with a gradient HPLC method fluid sciences. Combining operational excelpeaks and high bromate values, additional (All units in µg/L) lence and technology expertise with an intimethod development was done to ensure Sample BrO3– Br– mate understanding of its customers’ needs, the analyte of interest was adequately sepaAustralia — 38.1 PerkinElmer creates innovative solutions— rated from any other components that backed by unparalleled service and support— Brazil — 7.94 might mistakenly contribute to the bromate for customers in health sciences, semiconducSpain — 23.5 measurement. A gradient HPLC method, tor, aerospace and other markets whose Thailand-1 37.4 17.3 although slightly longer than the isocratic applications demand absolute precision and method developed for routine use, showed Thailand-2 76.0 — speed. The company markets in more than 125 several peaks overlapped the bromate peak Thailand-3 3.03 9.36 countries and is a component of the S&P 500 in some samples.2 Advanced interference Index. Additional information is available US-1 — 8.79 correction on the ICP-MS showed that the through www.perkin elmer.com or 1-877-PKIUS-2 — 224 additional peaks did, in fact, contain broNYSE. PerkinElmer Life and Analytical SciChina-1 20.8 7.41 mine. Their identification was not investiences at 710 Bridgeport Avenue, Shelton Conn. gated further. Figure 3 shows the China-2 16.1 11.9 06484 manufactures the Perkin Elmer Series chromatogram for a bottled water purChina-3 (Tap) — 380 200 HPLC and ELAN® DRC™ II ICP-MS, chased in Thailand showing the additional China-4 14.0 11.8 using Chromera™ software, the measuring depeak, uncovered with the gradient separavices used for this research. China-5 (Tap) — 64.6 tion method. Table 1 shows the concentrations of bromide and bromate for a variety About the corresponding author of bottled and tap water samples. The samples with suspect 6 Zoe Grosser, Ph.D. is Segment Marketing Manager, Analytical peaks or bromate concentrations above the regulatory limit were Sciences of PerkinElmer Life and Analytical Sciences. She has been confirmed with the developed gradient HPLC separation to enwith the firm for more than 20 years, having held a variety of sure that only one peak was present at the retention time exmarketing, product development and product support roles. Prior to pected for bromate. joining PerkinElmer, she was an analytical problem solver at American Cyanamid. She obtained a doctorate in analytical chemistry from Summary Northeastern University and holds a Master’s in business administraSpeciation development continues in this improvement of tion/marketing from the University of Connecticut. Grosser can be existing methodology. The separations are accomplished in less reached via email at [email protected] or telephone: (203) than three minutes and proved to be repeatable from injection 402-5320. to injection and over several days. For those waters containing additional bromine-containing species, a gradient HPLC Reprinted with permission of Water Conditioning & Purification Magazine ©2007 Water Conditioning & Purification
AUGUST 2007
