An optimized analytical method for the simultaneous detection of iodoform, iodoacetic acid, and other trihalomethanes and haloacetic acids in drinking water

Development and validation of a GC-MS/MS method for the determination of iodoacetic acid in biological samples

Iodoacetic acid (IAA) is a halogenated disinfection by-product of growing concern due to its high cytotoxicity, genotoxicity, endocrine disruptor effects, and potential carcinogenicity. However, the data on distribution and excretion of IAA after ingestion by mammals are still scarce. Here, we developed a reliable and validated method for detecting IAA in biological specimens (plasma, urine, feces, liver, kidney, and tissues) based on modified QuEChERS sample preparation combined with gas chromatography-tandem triple quadrupole mass spectrometry (GC-MS/MS). The detection method for IAA exhibited satisfactory recovery rates (62.6-108.0%) with low relative standard deviations (RSD < 12.3%) and a low detection limit for all biological matrices ranging from 0.007 to 0.032 ng/g. The study showed that the proposed method was reliable and reproducible for analyzing IAA in biological specimens. It was successfully used to detect IAA levels in biological samples from rats given gavage administration. The results indicated that IAA was found in various tissues and organs, including plasma, thyroid, the liver, the kidney, the spleen, gastrointestinal tract, and others, 6 h after exposure. This study provides the first data on the in vivo distribution in and excretion of IAA by mammals following oral exposure.

A New Method for the Fast Analysis of Trihalomethanes in Tap and Recycled Waters Using Headspace Gas Chromatography with Micro-Electron Capture Detection

Chemical disinfection of water supplies brings significant public health benefits by reducing microbial contamination. The process can however, result in the formation of toxic compounds through interactions between disinfectants and organic material in the source water. These new compounds are termed disinfection by-products (DBPs). The most common are the trihalomethanes (THMs) such as trichloromethane (chloroform), dichlorobromomethane, chlorodibromomethane and tribromomethane (bromoform); these are commonly reported as a single value for total trihalomethanes (TTHMs). Analysis of DBPs is commonly performed via time- and solvent-intensive sample preparation techniques such as liquid–liquid and solid phase extraction. In this study, a method using headspace gas chromatography with micro-electron capture detection was developed and applied for the analysis of THMs in drinking and recycled waters from across Melbourne (Victoria, Australia). The method allowed almost complete removal of the sample preparation step whilst maintaining trace level detection limits (>1 ppb). All drinking water samples had TTHM concentrations below the Australian regulatory limit of 250 µg/L but some were above the U.S. EPA limit of 60 µg/L. The highest TTHM concentration was 67.2 µg/L and lowest 22.9 µg/L. For recycled water, samples taken directly from treatment plants held significantly higher concentrations (153.2 µg/L TTHM) compared to samples from final use locations (4.9–9.3 µg/L).

A fully-automated analyzer for determining haloacetic acid concentrations in drinking water

A fully-automated, on-line, real-time analyzer has been developed for preconcentration and analysis of haloacetic acids (HAAs). Preconcentration of HAAs is achieved by sample acidification and solid phase extraction onto a hydrophobic polymeric resin using sequential injection analysis (SIA). The HAAs preconcentrate is then analyzed using post-column reaction-ion chromatography (PCR-IC), which is selective for HAAs. Systematic optimization of SIA preconcentration parameters are described followed by detailed method detection limit (MDL), accuracy, precision, and linearity studies. MDL values for the individual HAA9 species range from 0.4 to 0.9 μg L(-1). Side-by-side comparison studies of HAAs analysis in 14 real-world drinking water samples from Alabama, Arkansas, Kentucky, Minnesota, Missouri, Mississippi, New York, Pennsylvania and Tennessee are presented that compare the optimized SIA-PCR-IC to USEPA Method 552.3. Trace levels of HAAs detected in select samples are reported, and the bias values calculated between the two methods are typically less than 5 μg L(-1) for eight of the nine individual HAAs.