LC-MS analysis of nitroguanidine compounds by catalytic reduction using palladium modified graphitic carbon nitride catalyst.

The analysis of compounds of the nitroguanidine family at trace level poses an analytical challenge. Nitroguanidine, 1-methyl-3-nitroguanidine, and 1-methyl-3-nitro-1-nitrosoguanidine, which are addressed in this article, have low lipophilicity, with log(K) equal to -0.89, - 0.

Modeling sewage leakage and transport in carbonate aquifer using carbamazepine as an indicator.

The Western Mountain Aquifer (Yarkon-Taninim) of Israel is one of the country's major water resources and partially flows through a karst system. During late winter 2013, maintenance actions were performed on a central sewage pipe that caused sewage to leak into the creek located in the study area. Carbamazepine (CBZ) was used as an indicator for the presence of sewage in the groundwater.

Sensitive Analysis of Nitroguanidine in Aqueous and Soil Matrices by LC-MS.

Nitroguanidine, a widely used nitramine explosive, is an environmental contaminant that is refractory, persistent, highly mobile in soils and aquifers, and yet under-researched. Nitroguanidine determination in water and soil poses an analytical challenge due its high hydrophilicity, low volatility, charge neutrality over a wide pH range, and low proton affinity which results in low electrospray interface (ESI)-MS sensitivity. A sensitive method for the determination of nitroguanidine in aqueous and soil matrices was developed.

Puddles - A trigger for heterogeneous chemical influx into the unsaturated zone.

Spatial heterogeneity in the chemical concentration of interstitial water in the vadose zone was previously observed under apparently homogeneous surface conditions on two leveled fields sprinkler irrigated with treated sewage effluents on the phreatic Coastal Plain aquifer of Israel. This phenomenon greatly hampers the monitoring of groundwater quality. In this study we report on the presence of puddles of different size and shape that were sporadically observed in these fields.

Quantitative evaluation of tracers for quantification of wastewater contamination of potable water sources.

Quantitative criteria for selection of tracers for assessment of mixing of wastewater and pristine water are proposed and evaluated for leakage from a wastewater effluent recharge system to nearby pristine water wells and the dilution of the effluents in a reclamation well by pristine water from the surrounding aquifer. Two molecular tracers were compared: carbamazepine, an organic drug whose refractory behavior was evaluated on-site, and chloride, a widely used conservative tracer. The mixing ratios and the corresponding uncertainty levels in their calculation were evaluated using actual field data.