共找到 150 条与 1,4-二氧六环 相关的标准，共 10 页
本标准规定了化学试剂1，4—二氧六环的技术要求、试验方法、检验规则和包装及标志。
Chemical reagent 1,4-Dioxane
本标准适用于化学试剂1,4-二氧六环的质量检验，规定了其技术要求、试验方法、检验规则及包装标志。
Chemical reagent - 1,4-Dioxane
本标准规定了超干试剂1,4-二氧六环的规格、试验、检验规则和包装及标志。 本标准适用于超干试剂1,4-二氧六环的检验。
Super dry reagent—1,4-Dioxane
1,4-dioxan for analytical purposes
This powerpoint presentation begins by providing a brief overview of the sources and health effects of 1,4-Dioxane. Treatment process effectiveness is presented, along with the bench scale treatment process train: lime softening, ozone, BAC, and chloramines. The bench scale treatment method is presented, along with the impact of initial dioxane concentration and temperature, a cost comparison of 50% 1,4-Dioxane removal vs 90% 1,4-Dioxane removal, greenhouse gas emissions comparison of 50% 1,4-Dioxane removal vs 90% 1,4-Dioxane removal. Presentation summary: 1,4-Dioxane is difficult to remove from water; UV/Hydrogen peroxide is effective, but energy intensive; and, ozone followed by biological filtration is an economical removal method, and more sustainable. Includes figures.
New Information on Lower Cost Methods to Remove 1,4-Dioxane
An ultraviolet light coupled with titanium dioxide (UV/TiO<sub>2</sub>) advanced oxidation pilot system was evaluated at the Greenbrook Water Treatment Plant. The objective of the pilot study was to evaluate the effect of varying operating parameters on the performance of the UV/TiO<sub>2</sub> system for the concurrent degradation of 1,4-dioxane and removal of iron and manganese through adsorption onto the TiO<sub>2</sub> surface. It was hypothesized that as iron and manganese adsorb onto the TiO<sub>2</sub> surface, the degradation of 1,4-dioxane would be impaired. This pilot study showed promising results that suggest UV/TiO<sub>2</sub> advanced oxidation is capable of concurrent treatment of multiple contaminants. Effective iron removal was achieved under all tested conditions, while the effective removal of manganese and degradation of 1,4-dioxane was dependent on operating conditions. A lower flow rate (8 L/min) was required for both the removal of manganese under alkaline conditions (pH 8.6), and the degradation of 1,4-dioxane under acidic conditions (pH 5.5) or in the presence of peroxide (30 mg/L). Thus, the pilot UV/TiO<sub>2</sub> system is able to concurrently remove iron with either manganese or 1,4-dioxane, but the effective removal of manganese and degradation of 1,4-dioxane are competing processes. Results suggest that a higher UV dose (lower flow rate, more UV lamps, or more powerful UV lamps) needs to be applied in order to effectively remove all three contaminants. Includes 26 references, figures.
UV/TiO2 for Drinking Water Treatment: Concurrent Degradation of 1,4-Dioxane and Removal of Iron and Manganese
This slide presentation outlines a project where, in 2004, the Regional Municipality of Waterloo (RMOW) shut down its Greenbrook Water Treatment Plant when 1,4-dioxane was found in well supply up to 285 ppb. Associated Engineering was hired to conduct a Treatability Study that included a Literature Review, Bench-Scale Study, and a Pilot-Scale Study. Objectives of the Pilot-Scale Tests included: demonstrate 1,4-dioxane destruction with 3 advanced oxidation processes (AOPs) and their suitability at Greenbrook: UV / H<sub>2</sub>O<sub>2</sub>; O<sub>3</sub> / H<sub>2</sub>O<sub>2</sub>; UV / TiO<sub>2</sub>; O<sub>3</sub> dosing control (O<sub>3</sub> / H<sub>2</sub>O<sub>2</sub> only); monitor bromate formation, if any; confirm improvement with upstream filtration; examine level of Fe / Mn removal through AOP; and, determine H<sub>2</sub>O<sub>2</sub> residual for future quenching considerations. Raw water quality considerations and pilot process train are outlined along with the pilot study summary that includes: filtration process confirmed Fe/Mn removal; minimal improvement for downstream AOP; 1,4-Dioxane removal and byproduct formation; and, all AOPs tested were able to meet low target dioxane levels (< 10 µg/L) without forming high levels of bromate.
Treatment of 1,4-Dioxane in Groundwater Using Advanced Oxidation Processes: UV/H2O2, O3/H2O2, and UV/TiO2
1,4-dioxane is commonly found in treated wastewater effluent and landfill leachate due to the extensive use of 1,4-dioxane as a stabilizer for chlorinated solvents such as 1,1,1-trichloroethane (TCA) and a contaminant in some surfactant compounds used in herbicides. Also a variety of personal care products such as shampoo, liquid soaps, sunscreens, moisturing lotions, baby lotions, and hair lotions contained 1,4-dioxane with levels ranging from 3 to 100 parts per million. As more occurrences and distributions of 1,4-dioxane were reported in several states including California, the interest in a reliable and fast analytical method to detect sub ppb levels 1,4-dioxane has increased. Recently, 1,4-dioxane, which the US Environmental Protection Agency (USEPA) classifies as a B2 probable human carcinogen, has been detected in the specific ground and surface waters. The findings of 1,4-dioxane in the water systems prompted the need of extensive monitoring of the compound in the drinking water. But the currently available methods have high detection limits of 10 to 50 ug/L. The high reportable detection limits are the results of poor extraction efficiency and volatile nature of the compound. The Orange County Water District (OCWD) Laboratory has reviewed currently available isotope dilution methods and purge-trap techniques using the GC/MS. Most laboratories are applying the isotope dilution method, but the isotope dilution method involves labor-intensive liquid- liquid extraction and 100-200 ml of methylene chloride for each sample. Due to the poor purging efficiency and infinite water solubility of 1,4- dioxane, the detection limit of purge-trap techniques is 100 times higher than the other purgeable compounds with USEPA method 524.2. The OCWD lab has initiated a series of modifications for the purge-trap extraction and instrumentation of USEPA method 524.2 to improve the sensitivity and reproducibility for the determination of 1,4-dioxane in water. To improve purging efficiency, the purge time has been increased to 20 minutes from 11 minutes instead of increasing the purge flow of 40 ml/minute to prevent foaming of the heavy matrix samples. Also a different type of trap, which contains more carbopack(TM), could improve the response and the shape of 1,4-dioxane peak. For the instrumentation, the GC/MS/MS has been applied to retrieve the ions from GC/MS, which removed the background ions to help the identification of low ppb levels of 1,4-dioxane from wastewater samples. The improved method generated the method detection limit of 0.2 ppb and very reproducible data without manual labor and using only 25 ml of sample compared to the 1000 ml-sample extraction of the isotope dilution method. The split test between purge-trap and isotope dilution method showed the excellent correlation for drinking water and wastewater samples. The improved purge-trap and GC/MS/MS techniques will be very resourceful in saving labor and 100% solvent less extraction with fast turn-around time, high precision, and comparable sensitivity to the isotope dilution method. Includes 6 references, tables.
Improved Purge-Trap and GC/MS/MS Techniques for the Trace-Level Determination of 1,4-Dioxane in Water
Orange County Water District (OCWD) Laboratory has developed a cost-effective and very sensitive detection method for NDMA and 1,4-dioxane using GC/MS/MS/CI and GC/MS/MS/Purge-Trap, respectively. Since the demand of these methods is very high to process over 2,000 samples each year. The lab initiated the multi-residual analytical method to incorporate 1,4-dioxane with the existing analytical method for nitrosamines. The solid phase extraction (SPE) with 80 to 100 meshes of granular carbon uses 10 ml of methylene chloride for extracting the interested analytes from the absorbent materials. The 10 ml extract was concentrated to final volume of 1ml to be analyzed by GC/MS/MS with positive chemical ionization with methanol reagent solution. The developed analytical method generated the acceptable recovery and precision for both nitrosamines and 1,4-dioxane for different matrix of aqueous samples such as groundwater, surface water and reclaimed water. The reportable detection limit of 1,4-dioxane was 0.05 parts per billion while the purge-trap method was 1.0 part per billion. Recently, 1,4-dioxane, which the US Environmental Protection Agency classifies as a B2 probable human carcinogen, has been detected in the specific ground and surface waters. The findings of 1,4-dioxane in the water systems prompted the need of extensive monitoring of the compound in the drinking water. But the currently available methods have high detection limits of 10 to 50 ug/L. The high reportable detection limits are the results of poor extraction efficiency and volatile nature of the compound. Orange County Water District (OCWD) Laboratory has examined extraction and analysis techniques to establish a more sensitive and reliable method to analyze for 1,4-dioxane to less than 1 ug/L in drinking water samples. OCWD Laboratory has been developed a very reliable method to determine sub part per trillion levels of N-nitrosodimethylamine (NDMA) by GC/MS using positive chemical ionization with methanol or acetonitrile. Since 1,4-dioxane and nitrosamines have similar properties, very water soluble, volatile and polar, 1,4- dioxane was successfully included in the existing method for nitrosamines. To accommodate 1,4-dioxane into the existing analytical method, 1,4-dioxane-d8 and NDPA-d14 were both used as internal standards. The pH of 500 mL sample was adjusted between 4 and 11 and extracted three times with 60 ml of methylene chloride. The extract was evaporated to 1 ml using nitrogen gas at 35 celsius degrees in a water bath. The retention times of 1,4-dioxane and NDMA were 11.43 and 11.86 minutes with 60 m capillary column, respectively. The retention time differences of 0.43 minutes was far enough to change chemical ionization settings from 1,4-dioxane to NDMA, which multiple settings are necessary to perform simultaneous determination of these compounds without decreasing instrument sensitivity. The modified extraction and instrument techniques generated method detection limits, as the basis of a 1 L sample size, range from 0.1 to 0.2 ug/L for 1,4-dioxane and 0.2 to 0.3 ng/L for NDMA. For the positive chemical ionization, methanol or acetonitrile have several advantages over ammonia gas for safety and system maintenance. Also, the modified liquid-liquid extraction technique using separatory funnel could save 80% of extraction time compared to the continuous liquid-liquid extraction technique. The results of recent work on the analysis of 1,4-dioxane and NDMA from groundwater, surface water and reclaimed water samples are included. This study clearly demonstrated the GC/MS using chemical ionization with methanol was very sensitive, reliable and cost effective for the simultaneous analysis of 1,4- dioxane and NDMA from aqueous samples. Includes 12 references, table.
Simultaneous Analytical Method for 1,4- Dioxane and N-Nitrosomamines Using Solid Phase Extraction and GC/MS/MS/CI from Aqueous Samples
Metode uji penentuan kadar 1,4-dioksan dalam produk kosmetik secara headspace kromatografi gas spektrometri massa
Surfactants - Determination of 1,4-dioxane content in ethoxylated alkyl sulfates by CGL/Headspace
ADOPTED_FROM:EN 12974:1999 This European Standard specifies a gas-liquid chromatography (GLC)/head space method for the determination of 1,4-dioxane in alkyl-ethoxy-sulfate products. The method is applicable to samples containing 1,4-dioxane in the range from 5 mg/kg to 100 mg/kg.
Surface active agents — Determination of the 1,4-dioxane content in alkyl-ethoxy-sulfate products by GLC/head space procedure
The California Department of Health Services (CADHS) sets the reportable detection limits at 5 parts per trillion for 1,2,3-trichloropropane and 3 parts per billion for 1,4- dioxane. Due to the demand of low-level detection limit and poor purging efficiency of these compounds, the existing purge and trap techniques and instrumentation could not meet the detection requirements set by CADHS. The available liquid-liquid extraction method requires a 1L sample, 200 ml of organic solvents, and 16 hours of reaction to extract these compounds from water matrix. The Orange County Water District (OCWD) has developed a very reliable and sensitive method without using any organic solvents and manual labor for a sample extraction. Since 1,2,3-trichloropropane and 1,4-dioxane both are very water-soluble and volatile, the improved purge and trap techniques could separate these compounds. 20 minutes of purging with 40 ml/min of helium and 15 minutes of baking at 260 C for trap increased the purging efficiency more than 2 times. Also, the interested ions are further retrieved by multiple mass spectrometry technology, which improved the sensitivity of the system more than 50 times than normal mass spectrometry. The retention time of 1,2,3-trichloropropane is 26.4 min and 17.1 min for 1,4-dioxane. The method detection limits of 1,2,3-trichloropropane and 1,4- dioxane based on 25 ml of the sample volume are reported as 1.4 parts per trillion and 0.1 parts per billion, respectively. The improved purge and trap techniques using multiple mass spectrometry could save 90% of extraction time and 100% of solvent consumption compared to the continuous liquid-liquid extraction technique without sacrificing these detection limits and reliability of the analysis. The developed techniques have been successfully applied to monitor groundwater contamination and increase the removal efficiency of these compounds by wastewater treatment facility using microfiltration and ultraviolet irradiation. Includes 12 references, tables.
Simultaneous Determination of 1,2,3-Trichloropropane and 1,4-Dioxane in Drinking Water by GC/MS/MS Using Purge and Trap Techniques
Opisano metodę GLC/head space do oznaczania zawartości 1,4-dioksanu w oksyetylenowanych alkilosiarczanach. Podano zakres stosowania normy, zasadę metody, odczynniki i aparaturę, kalibrację, sposób przygotowania i przechowywania próbek, sposób wykonania badania, sposób wyrażania wyników i wymaganą precyzję
Surfactants -- Determination of 1,4-dioxane content in oxyethylenated alkyl sulfate products by GLC/head space method
Surface active agents - Determination of the 1,4-dioxane content in alkyl-ethoxy-sulfate products by GLC/head space procedure
