Detection of monobromamine, monochloramine and dichloramine using selected ion flow tube mass spectrometry and their relevance as breath markers

Simultaneous time-resolved inorganic haloamine measurements enable analysis of disinfectant degradation kinetics and by-product formation

We demonstrate the application of proton transfer time-of-flight mass spectrometry (PTR-TOF-MS) in monitoring the kinetics of disinfectant decay in water with a sensitivity one to three orders of magnitude greater than other analytical methods. Chemical disinfection inactivates pathogens during water treatment and prevents regrowth as water is conveyed in distribution system pipes, but it also causes formation of toxic disinfection by-products. Analytical limits have hindered kinetic models, which aid in ensuring water quality and protecting public health by predicting disinfection by-products formation. PTR-TOF-MS, designed for measuring gas phase concentrations of organic compounds, was able to simultaneously monitor aqueous concentrations of five inorganic haloamines relevant to chloramine disinfection under drinking water relevant concentrations. This novel application to aqueous analytes opens a new range of applications for PTR-TOF-MS.

Inorganic chloramines: a critical review of the toxicological and epidemiological evidence as a basis for occupational exposure limit setting

Inorganic chloramines are not commercially available, but monochloramine is produced in situ for disinfection or for use in chemical synthesis. Inorganic chloramines are also formed when free chlorine reacts with nitrogen containing substances, e.g. ammonia and urea, present in chlorinated water sources. Occupational exposure may, therefore, occur in e.g. swimming pool facilities and the food processing industry. Monochloramine is soluble and stable in water and the dominating inorganic chloramine in chlorinated water sources. No clinical effects were seen in healthy volunteers given monochloramine in drinking water during 4 or 12 weeks in doses of 0.043 or 0.034 mg/kg bw/day, respectively. Limited data indicate that monochloramine is weakly mutagenic in vitro but not genotoxic in vivo. One drinking water study indicated equivocal evidence of carcinogenicity in female rats but not in male rats and mice. No reproductive or developmental effects were shown in rodents in the few studies located. Dichloramine is soluble but unstable in water. In the only study located, mild histological effects in kidneys, thyroid and gastric cardia were observed in rats administered dichloramine in drinking water for 13 weeks. Trichloramine is immiscible with water and evaporates easily from water into air. Therefore, the primary exposure route of concern in the occupational setting is inhalation. Occupational exposure to trichloramine has been demonstrated in indoor swimming pool facilities and in the food processing industry where chlorinated water is used for disinfection. Exposure-response relationships between airborne levels and self-reported ocular and upper airway irritation have been shown in several studies. Exposure to trichloramine may aggravate asthma symptoms in individuals with existing asthma. The risk of developing asthma following long-term exposure to trichloramine cannot be evaluated at present. No data on genotoxic, carcinogenic, reproductive or developmental effects were located. The toxicological data for mono- and dichloramine are insufficient to recommend health-based occupational exposure limits (OELs).As regard trichloramine, the critical effect is judged to be irritation observed in several studies on pool workers, starting at approximately 0.4 mg/m³ (stationary sampling). Based on these data, a health-based OEL of 0.1 mg/m³ (8-h time-weighted average) is recommended. This corresponds to 0.2 mg/m³ for stationary measurements in swimming pool facilities. No short-term exposure limit (STEL) is recommended.

Evidence of Reactivity in the Membrane for the Unstable Monochloramine during MIMS Analysis

Membrane Inlet Mass Spectrometry (MIMS) was used to analyze monochloramine solutions (NH₂Cl) and ammonia solutions in a compact FTICR. Chemical ionization enables identification and quantification of the products present in the permeate. The responses of protonated monochloramine and ammonium increase linearly with the solution concentration. The enrichments were respectively 1.2 and 5.5. Pervaporation is dependent on pH and only the basic form of ammonia NH₃ pervaporates through the membrane. Unexpectedly, the small ammonia molecule permeated very slowly. It could be due to interactions with water molecules inside the membrane that create clusters. Moreover, NH₂Cl solutions, in addition to the NH₃Cl⁺ signal, presented a strong NH₄⁺ signal at m/z 18.034. Ammonia presence in the low-pressure zone before ionization is probable as NH₄⁺ was detected with all the precursors used, particularly CF₃⁺ and trimethylbenzene that presents a proton affinity higher than monochloramine. Ammonia may be formed inside the membrane due to the fact that NH₂Cl is unstable and may react with the water present in the membrane. Those results highlight the need for caution when dealing with chloramines in MIMS and more generally with unstable molecules.

Gene expression changes in blood RNA after swimming in a chlorinated pool

Exposure to disinfection by-products (DBP) such as trihalomethanes (THM) in swimming pools has been linked to adverse health effects in humans, but their biological mechanisms are unclear. We evaluated short-term changes in blood gene expression of adult recreational swimmers after swimming in a chlorinated pool. Volunteers swam 40min in an indoor chlorinated pool. Blood samples were drawn and four THM (chloroform, bromodichloromethane, dibromochloromethane and bromoform) were measured in exhaled breath before and after swimming. Intensity of physical activity was measured as metabolic equivalents (METs). Gene expression in whole blood mRNA was evaluated using IlluminaHumanHT-12v3 Expression-BeadChip. Linear mixed models were used to evaluate the relationship between gene expression changes and THM exposure. Thirty-seven before-after pairs were analyzed. The median increase from baseline to after swimming were: 0.7 to 2.3 for MET, and 1.4 to 7.1μg/m³ for exhaled total THM (sum of the four THM). Exhaled THM increased on average 0.94μg/m³ per 1 MET. While 1643 probes were differentially expressed post-exposure. Of them, 189 were also associated with exhaled levels of individual/total THM or MET after False Discovery Rate. The observed associations with the exhaled THM were low to moderate (Log-fold change range: -0.17 to 0.15). In conclusion, we identified short-term gene expression changes associated with swimming in a pool that were minor in magnitude and their biological meaning was unspecific. The high collinearity between exhaled THM levels and intensity of physical activity precluded mutually adjusted models with both covariates. These exploratory results should be validated in future studies.

Progress in SIFT-MS: breath analysis and other applications

The development of selected ion flow tube mass spectrometry, SIFT-MS, is described from its inception as the modified very large SIFT instruments used to demonstrate the feasibility of SIFT-MS as an analytical technique, towards the smaller but bulky transportable instruments and finally to the current smallest Profile 3 instruments that have been located in various places, including hospitals and schools to obtain on-line breath analyses. The essential physics and engineering principles are discussed, which must be appreciated to design and construct a SIFT-MS instrument. The versatility and sensitivity of the Profile 3 instrument is illustrated by typical mass spectra obtained using the three precursor ions H(3)O(+), NO(+) and O(2)(+)·, and the need to account for differential ionic diffusion and mass discrimination in the analytical algorithms is emphasized to obtain accurate trace gas analyses. The performance of the Profile 3 instrument is illustrated by the results of several pilot studies, including (i) on-line real time quantification of several breath metabolites for cohorts of healthy adults and children, which have provided representative concentration/population distributions, and the comparative analyses of breath exhaled via the mouth and nose that identify systemic and orally-generated compounds, (ii) the enhancement of breath metabolites by drug ingestion, (iii) the identification of HCN as a marker of Pseudomonas colonization of the airways and (iv) emission of volatile compounds from urine, especially ketone bodies, and from skin. Some very recent developments are discussed, including the quantification of carbon dioxide in breath and the combination of SIFT-MS with GC and ATD, and their significance. Finally, prospects for future SIFT-MS developments are alluded to.

Monitoring chloramines and bromamines in a humid environment using selected ion flow tube mass spectrometry

The selectivity and sensitivity of selected ion flow tube mass spectrometry (SIFT-MS) for individual breath analysis of haloamines has been improved by heating the flow tube in a commercial instrument to around 106 degrees C. Data is presented showing the marked reduction in the number density of water clusters of product ions of common breath metabolites that are isobaric with the product ions from monochloramine and monobromamine that are used to monitor the haloamine concentrations. These results have direct relevance to the real-time monitoring of chloramines in drinking water, swimming pools and food processing plants. However, once the isobaric overlaps from water cluster ions are reduced at the higher temperatures, there is no conclusive evidence showing the presence of haloamines on single breath exhalations in the mid parts per trillion range from examination of the breaths of volunteers.

Interference of chlorofluorocarbon (CFC)-containing inhalers with measurements of volatile compounds using selected ion flow tube mass spectrometry

Selected ion flow tube mass spectrometry (SIFT-MS) is a sensitive technique capable of measuring volatile compounds (VCs) in complex gas mixtures in real time; it is now being applied to breath analysis. We investigated the effect of inhalers containing chlorofluorocarbons (CFCs) on the detection and measurement of haloamines in human breath. SIFT-MS mass scans (MS) and selected ion monitoring (SIM) scans were performed on three healthy non-smoking volunteers before and after inhalation of the following medications: Combiventtrade mark metered-dose inhaler (MDI) (CFC-containing); Ventolintrade mark MDI (CFC-free); Atroventtrade mark MDI (CFC-free), Beclazonetrade mark MDI (CFC-containing); Duolintrade mark nebuliser. In addition, the duration of the persistence of the mass/charge ratios was measured for 20 h. Inhalers containing CFCs generated large peaks at m/z 85, 87, 101, 103 and 105 in vitro and in vivo, consistent with the predicted product ions of CFCs 12, 114 and 11. No such peaks were seen with Duolintrade mark via nebuliser, or CFC-free MDIs. We conclude that measurement of VCs, such as haloamines, with product ions of similar m/z values to the ions found for CFCs would be significantly affected by the presence of CFCs in inhalers. This issue needs to be accounted for prior to the measurement of VCs in breath in people using inhalers containing CFCs.

Selected ion flow tube mass spectrometry of exhaled breath condensate headspace

Collection of exhaled breath condensate (EBC) is a relatively simple noninvasive method of breath analysis; however, no data have been reported that would relate concentration of volatile compounds in EBC to their gaseous concentrations in exhaled air. The aim of the study was to investigate which volatile compounds are present in EBC and how their concentrations relate to results of direct breath analysis. Thus, samples of EBC were collected in a standard way from several subjects and absolute levels of several common volatile breath metabolites (ammonia, acetone, ethanol, methanol, propanol, isoprene, hydrogen cyanide, formaldehyde and acetaldehyde) were then determined in their headspace using selected ion flow tube mass spectrometry (SIFT-MS). Results are compared with those from on-line breath analyses carried out immediately before collecting the EBC samples. It has been demonstrated that SIFT-MS can be used to quantify the concentrations of volatiles in EBC samples and that, for methanol, ammonia, ethanol and acetone, the EBC concentrations correlate with the direct breath levels. However, the EBC concentrations of isoprene, formaldehyde, acetaldehyde, hydrogen cyanide and propanol do not correlate with direct breath measurements.