Trace Bromate Research Articles

Vortex- assisted liquid- liquid microextraction for the trace determination of potassium bromate in flour food products

Potassium bromate, also reported as a carcinogenic agent, commonly functions to improve flour in the baking industry to increase bread volume. In this study, a green and novel preconcentration and microextraction method, termed as vortex assisted liquid–liquid microextraction combined with UV–Vis spectrophotometry was developed and utilized for trace determination of Potassium Bromate in food samples. Furthermore, various chemometric methods have been used. Under optimum conditions, the linearity range was obtained in the range between 0.02 and 2 µg/mL. Using the proposed analytical approach, the detection limits and quantitation of KBrO3 were 0.02 and 0.07 µg/mL, respectively. A pre-concentration factor of 22.2 was reported. The precision of the method was evaluated in the terms of repeatability and reproducibility and expressed by the relative standard deviation; the levels of them were considerably higher than 5.07 and 4.8%. The proposed approach was applied to the determination of trace bromate in different flour products.

Determination of Trace Bromate in Drinking Water with High Chloride Matrix by Cyclic Ion Chromatography.

An ion chromatography (IC) system with switching recycling column was developed for the determination of bromate in drinking water with high chloride content. The system included a pump, two switching valves, guard column and analytical column, suppressor and a conductivity detector. In this method, the single eluent was used for both online collection and matrix elimination, and bromate was eluted from the concentrator column to the analytical column circularly. Under the optimized separation conditions, the method showed good linearity (r=0.9995) in the range of 1-100μg/L and repeatability (RSD≤4.80%, n=6). The limit of detection was 0.2μg/L (S/N=3) with 1000μL sample volume injections. The method was applied to analysis of drinking and tap waters, and satisfactory recoveries of spiked samples between 96.8% and 108.7% were obtained. The result showed that the recycling column-switching system can be useful for the determination of traces of bromate in high-chloride samples, which is required in production of the drinking water and quality control of the final product.

Determination of trace bromate in various water samples by direct-injection ion chromatography and UV/Visible detection using post-column reaction with triiodide

Bromate is a disinfection by-product generated mainly from the oxidation of bromide during the ozonation and disinfection process in order to remove pathogenic microorganism of drinking water, and classified as a possible human carcinogen by International Agency for Research of Cancer (IARC) and World Health Organization (WHO). For the purpose of determining the trace level concentration of bromate, several sensitive techniques are applied mostly based on suppressed conductivity detection and UV/Visible detection after postcolumn reaction (PCR). In this study, the suppressed conductivity detection method and the PCR-UV/Visible detection method through the triiodide reaction were compared to analyze the trace bromate in water samples and estimated for the availability of these analytical methods. In addtion, the state-of-the-art techniques was applied for the determination of trace level bromate in various water matrices, i.e., soft drinking water, hard drinking water, mineral water, swimming pool water, and raw water. In comparison of two analytical methods, it was found that the conductivity detection had the suitable advantage to simultaneously analyze bromate and inorganic anions, however, the bromate might not be precisely quantified due to the matrix effect especially by chloride ion. On the other hand, the trace bromate was analyzed effectively by the method of PCR-UV/ Visible detection through triiodide reaction to satisfactorily minimize the matrix interference of chloride ion in various water samples, showing the good linearity and reproducibility. Furthermore, the method detection limit (MDL) and recovery were 0.161 μg/L and 101.0–108.1 %, respectively, with a better availability compared to conductivity detection.

Bromate peak distortion in ion chromatography in samples containing high chloride concentrations

In this study, the effect of column overload of the matrix ion, chloride, on the elution peak profiles of trace bromate is investigated. The resultant peak profiles of chloride and bromate are explained on the basis of competitive Langmuir isotherms. The Thermo IonPac AS9-HC, AS19 and AS23 columns are recommended by the manufacturer for bromate (a carcinogen) analysis. Under trace conditions, these columns provide baseline resolution of bromate from matrix ions such as chloride (Rs=2.9, 3.3 and 3.2, respectively for the three columns). Injection of 10–300mM chloride with both hydroxide and carbonate eluents resulted in overload on these columns. On the basis of competitive Langmuir isotherms, a deficiency in the local concentration of the more retained eluent in addition to analyte overload leads to fronting of the overloaded analyte peak. The peak asymmetries (B/A10%) for chloride changed from 1.0 (Gaussian) under trace conditions to 0.7 (fronting) at 300mM Cl− for IonPac AS9-HC, 0.9–0.6 for AS19 and 0.8–0.5, for AS23, respectively. The 10mM bromate peak is initially near Gaussian (B/A10%=0.9) but becomes increasingly distorted and pulled back into the chloride peak as the concentration of chloride increased. Increasing the eluent strength reduced the pull-back effect on bromate and fronting in chloride in all cases.

Determination of inorganic oxyhalide disinfection by-products in bottled water by EPA Method 326.0 for trace bromate analysis

An ion chromatography method with post-column reaction and optical detection, according to EPA Method 326.0, for the determination of bromate has been developed and validated in water samples. Optimization of reaction and operating conditions (post-column reagent and sulphuric acid regenerant flow rate) made possible to minimize the background noise and attain low detection limit. Employing a carbonate elluent (9.0 mM Na 2CO 3) at a flow rate of 1.1 ml/min and a sample loop of 250 μl, a detection limit for bromate of 0.33 μg/l and a quantification limit (LOQ) of 0.99 μg/l were generated. Under these conditions bromate and chlorite were separated (resolution factor >2.5) in an analysis time of less than 6.5 min and the important validation parameters were evaluated. Calibration curve in laboratory-grade water produced excellent regression in the range from LOQ up to 20μg/l in the order of r 2=0.99, whereas a range of applicability of 0.99 μg/l to 100 μg/l was confirmed. UV detector response (AU ⁎min/(μg/l)) was almost constant (± 2%) at various concentration levels. The recoveries obtained in the accuracy test for all aqueous matrices studied were in the 93.1–106% range and the intraday and interday precisions (expressed as coefficient of variation, CV) were smaller than 13.5%. Expanded uncertainty (95%) was calculated at various concentration levels according to propagation error theory (1±0.28 μg/l, 5±0.44 μg/l, 10±0.60 μg/l).

Flow Injection Determination of Trace Bromate in Salts using Spectrophotometric Detection Directly in-Line Coupled with Anion-Exchange Separation and Preconcentration

Flow Injection Determination of Trace Bromate in Salts using Spectrophotometric Detection Directly in-Line Coupled with Anion-Exchange Separation and Preconcentration

Simple and Rapid Determination of Trace Bromate by Flow Injection Analysis with Novel Spectrophotometric Detection System

飲料水中の極微量臭素酸イオンを定量するための新規な吸光検出反応とそれを用いたフローインジェクション（FI）システムを開発した．弱酸性溶液中（0.1 M H2SO4）で臭素酸イオンによるV(IV) の酸化と生成したV(V) のNitro-PAPS｛2-(5-Nitro-2-pyridylazo)-5-[N -n -propyl-N -(3-sulfopropyl)amino]phenol｝錯体の生成，及び592 nmにおける吸光度測定が流れシステム中で行われる．反応とマニフォールドに関係する諸因子について詳細に検討し，最適な反応条件及びマニフォールドの配置を設定した．2 mのサンプルループを用いた場合，0～0.05 ppmの範囲で直線性の良い検量線が得られ（相関係数0.999），1回の分析時間は約4分と迅速である．0.01 ppm BrO3−を繰り返し注入した場合の変動係数は0.6%（n = 3），検出下限（3 σ）は0.0004 ppmであった．本FIシステムに0.05 M NaClを溶離液とする陰イオン交換分離を容易にインライン直結することができ，検出感度及び選択性の向上を図ることができた．3 mのサンプルループでの検出下限（3 σ）は0.0002 ppmで，0.01 ppm BrO3−の繰り返し注入の変動係数が1.4%（n = 3）と再現性は良好であった．分析時間は約9分と迅速である．本FIシステムにより3都市の水道水及び瓶詰め飲料水に標準の臭素酸イオンを添加して分析した場合の回収率は96～104% と良好な結果であった．

Bromate analysis in groundwater and wastewater samples

Bromate (BrO(3)(-)) is a disinfection by-product formed during ozonation of potable water supplies containing bromide (Br(-)). Bromate has been classed by the World Health Organisation as a 'possible human carcinogen', leading to implementation of 10-25 microg L(-1)(as BrO(3)(-)) drinking water limits in legislative areas including the United States and European Union. Techniques have been developed for bromate analysis at and below regulatory limits, with Ion Chromatography (IC) coupled with conductivity detection (IC-CD), post-column reaction and ultra-violet (UV) detection (IC-PCR), or inductively coupled plasma-mass spectrometry detection (IC-ICPMS) in widespread use. The recent discovery of bromate groundwater contamination in a UK aquifer has led to a requirement for analysis of bromate in a groundwater matrix, for environmental monitoring and development of remediation strategies. The possibility of bromate-contaminated water discharge into sewage treatment processes, whether accidental or as a pump-and-treat strategy, also required bromate analysis of wastewater sources. This paper summarises techniques currently available for trace bromate analysis in potable water systems and details studies to identify a methodology for routine analysis of groundwater and wastewater samples. Strategies compared were high performance liquid chromatography (HPLC) with direct UV or PCR/UV detection, IC-CD, IC-PCR, and a simple spectrophotometric technique. IC-CD was the most cost-effective solution for simultaneous analysis of bromate and bromide within groundwater samples, having a 5 microg L(-1) detection limit of both anions with limited interference from closely-eluting species. Wastewater samples were successfully analysed for bromate only using HPLC with PCR/UV detection, with detection limits below 20 microg L(-1)(as BrO(3)(-)) and low interference. HPLC with direct UV detection was unsuitable for bromate analysis within the concentration range 50-5000 microg L(-1) which was required for this project, but column choice was shown to be a major factor in determining limits of detection. Spectrophotometry could not reproducibly determine bromate concentration, although the technique showed promise as a quick field method for high-level groundwater bromate analysis.

Collaborative study of EPA Method 317.0 for the determination of inorganic oxyhalide disinfection by-products in drinking water using ion chromatography with the addition of a postcolumn reagent for trace bromate analysis.

The development of the U.S. Environmental Protection Agency (EPA) Method 317.0 is initiated to provide a sufficiently sensitive and fundamental technique for the compliance monitoring of trace levels of bromate in drinking water. After a comparative evaluation of Method 317.0 and elimination of a chlorite interference, this method is tested by a collaborative study in order to determine the precision and bias of the method and evaluate its potential role as a future compliance-monitoring method for inorganic disinfection by-products (DBPs) and trace bromate. This technique provides a practical method for future compliance monitoring for all of the inorganic oxyhalide DBPs including trace concentrations of bromate.

Eliminating the chlorite interference in US Environmental Protection Agency Method 317.0 permits analysis of trace bromate levels in all drinking water matrices

A post-column reagent (PCR) method for bromate analysis in drinking water with a method detection limit (MDL) and method reporting limit (MRL) of 0.1 and 0.5 μg/l, respectively, has been developed by the United States Environmental Protection Agency (EPA) for future publication as EPA Method 317.0. The PCR method provides comparable results to the EPA’s Selective Anion Concentration (SAC) method used to support the laboratory analysis of Information Collection Rule (ICR) low-level bromate samples and offers a simple, rugged, direct injection method with potential to be utilized as a compliance monitoring technique for all inorganic Disinfectants/Disinfection By-Products (D/DBPs). It has superior sensitivity for bromate compared to EPA Method 300.1, which was promulgated as the compliance monitoring method for bromate under Stage 1 of the D/DBP rule. This paper addresses elimination of the chlorite interference that was previously reported in finished waters from public water systems (PWSs) that employ chlorine dioxide as the disinfectant. An evaluation of Method 317.0 for the analysis of bromate in commercial bottled waters is also reported.

臭素酸のフロー電位差分析に用いた臭素酸イオンと臭化物イオンおよび鉄（ＩＩ）イオン間の反応の過程とその反応速度

臭素酸のフロー電位差分析に用いた臭素酸イオンと臭化物イオンおよび鉄（ＩＩ）イオン間の反応の過程とその反応速度