Quantification Of Organic Contaminants Research Articles

Supramolecular solvent extraction and ambient mass spectrometry for the determination of organic contaminants in food packaging material

A rapid method based on a fast sample treatment with supramolecular solvents (SUPRASs) and ambient mass spectrometry (AMS) analysis was developed for the screening and quantification of organic contaminants in food packaging materials (FCMs). The suitability of SUPRASs made up of medium chain alcohols in ethanol:water mixtures was investigated, given their low toxicity, proven capacity for multi-residue analysis (since they provide a wide variety of interactions and multiple binding sites) and restricted access properties for simultaneous sample extraction and clean-up. Two families of emerging organic pollutants, bisphenols and organophosphate flame retardants, were targeted as representative compounds. The methodology was applied to 40 FCMs. Target compounds were quantitated using ASAP (atmospheric solids analysis probe)-low resolution MS and a broad-spectrum screening of contaminants was performed through spectral library search using direct injection probe (DIP) and high resolution MS (HRMS). The results showed the ubiquity of bisphenols and of some flame retardants, as well as the presence of other additives and unknown compounds in about half of the analyzed samples, which highlight the complex composition of FCMs and the possible associated health risks.

Identification and Quantification of Organic Contaminants and Evaluation of Their Effects on Amine Foaming in the Natural Gas Sweetening Industry.

Contamination is a leading cause of corrosion, foaming, and amine-absorption capacity limitation, predominantly foaming. There is currently an urgent need to identify the sources of amine foaming and eliminate them or reduce their impacts. Gas chromatography-mass spectrometry (GC-MS) and a sample pretreatment method were developed to identify and quantify the organic contaminants. Linear hydrocarbons (C12-C22), long-chain carboxylic acids and esters, alcohol ethoxylates, and benzene derivatives were detected, characterized, and quantified in amine solutions. Furthermore, the effects of the contaminant concentrations on foaming behavior were also investigated by adding those contaminants. The results reveal that the main issue of foaming is due to the presence of unsaturated fatty acids and alcohol ethoxylates, even with a small amount of 10 ppm, whereas benzene derivatives like methylpyridine, quinoline, methyl naphthalene, benzyl alcohol, octahydroacridine, and linear hydrocarbons have little effect on amine foaming, even with an amount up to 2000 ppm. Therefore, it is necessary to monitor the existence and content of these surface-active contaminants.

Use of Hyperspectral Imaging for the Quantification of Organic Contaminants on Copper Surfaces for Electronic Applications

To correctly assess the cleanliness of technical surfaces in a production process, corresponding online monitoring systems must provide sufficient data. A promising method for fast, large-area, and non-contact monitoring is hyperspectral imaging (HSI), which was used in this paper for the detection and quantification of organic surface contaminations. Depending on the cleaning parameter constellation, different levels of organic residues remained on the surface. Afterwards, the cleanliness was determined by the carbon content in the atom percent on the sample surfaces, characterized by XPS and AES. The HSI data and the XPS measurements were correlated, using machine learning methods, to generate a predictive model for the carbon content of the surface. The regression algorithms elastic net, random forest regression, and support vector machine regression were used. Overall, the developed method was able to quantify organic contaminations on technical surfaces. The best regression model found was a random forest model, which achieved an R2 of 0.7 and an RMSE of 7.65 At.-% C. Due to the easy-to-use measurement and the fast evaluation by machine learning, the method seems suitable for an online monitoring system. However, the results also show that further experiments are necessary to improve the quality of the prediction models.

Quantification of organic contaminants in urban stormwater by isotope dilution and liquid chromatography-tandem mass spectrometry

Pollutants transported in urban stormwater runoff induce pervasive water quality degradation in receiving waters. To accurately characterize stormwater quality and treatment system performance across the range of possible contaminant characteristics, comprehensive multi-residue analytical methods are necessary. Here, we developed a solid-phase extraction (SPE) and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method to quantify representative stormwater-derived organic contaminants across multiple chemical classes, including vehicle-related chemicals, corrosion inhibitors, industrial chemicals, pesticides, pharmaceuticals and personal care products, and antioxidants. Extraction conditions, isotope-labeled internal standards, and LC-MS/MS parameters were optimized to enhance recovery, minimize matrix effects, and maximize selectivity and sensitivity. The developed method was sensitive (method quantification limits < 10 ng/L for > 80% of selected analytes) and accurate (mean relative recoveries in the range of 70-130%, with relative standard deviations < 25% for 77% of the analytes) for most of the analytes. The method was used to analyze samples collected from nine urban watersheds during a storm event; 62% of the 39 analytes were detected at least once at concentrations up to 540 ng/L (1,3-diphenylguanidine). Spatial trends in detection and concentration were observed for vehicle-related and industrial chemicals that correlated with vehicle traffic. Total concentrations of pesticides suggested that residential uses could be more important sources than agriculture. This study illustrates the pervasive occurrence of a wide variety of stormwater-derived chemicals in urban receiving waters and highlights the need to better understand their environmental fate and ecological implications. Graphical abstract.

A rapid and economical method for the quantification of hydrogen peroxide (H2O2) using a modified HPLC apparatus

H2O2 is one of the most commonly used oxidants for the degradation of recalcitrant organic contaminants in advanced oxidation processes (AOPs). However, most research aiming to optimize AOPs is missing the monitoring of the remaining H2O2, an important parameter to assess the efficiency of the process. In this work, a novel method for [H2O2] quantification was developed using simple modifications of an HPLC-DAD setup that is available in most analytical chemistry laboratories. The modifications include the use of acidified potassium iodide solution as mobile phase and replacing the reverse phase column with a series of capillary columns. This instrument configuration allowed also the quantification of organic contaminants using the same H2O2 containing sample. The method's LOD and LOQ were calculated to be as low as 8.29 × 10−4 mM and 2.76 × 10−3 mM, respectively with an LDR range of 0.01–150 mM. The cost per analysis ranged between 0.8 and 1.8 USD cents depending on the concentration tested. This analytical method was validated by a statistical comparison to a well-known titrimetric method that is commonly used for H2O2 quantification. It was also tested using standards prepared in natural matrices such as spring and seawater, and in media containing high concentration of several spectator species such as chlorides, bicarbonates, humic acids, fumaric acids and micro pollutants. The method showed excellent robustness by maintaining high regression coefficient and excellent sensitivity in all calibration curves regardless of the matrix content.

Computation Program System for Structural Analysis and Quantification of Organic Contaminants on Silicon Wafer Surfaces from Mass Spectra

A computer program was developed for the identification and quantification of organic contaminants on silicon wafer surfaces and related materials based on GC/MS spectral data. Information, such as the retention time (RT), mass number and peak intensity, was stored on 359 chemical compounds in the database. Some empirical equations were presented for calculating the existence probabilities of certain organic compounds. This method was confirmed for the identification and quantification of ultratrace organic contaminants on silicon wafer surfaces and related materials.

Optimization of purging efficiency and quantification of organic contaminants from water using a 1-L closed-loop-stripping apparatus and computerized capillary column GC/MS

Optimization of purging efficiency and quantification of organic contaminants from water using a 1-L closed-loop-stripping apparatus and computerized capillary column GC/MS

Determination of organic contaminants by the Grob closed‐loop‐stripping technique

A modified Grob closed‐loop‐stripping device is currently being used to concentrate organic contaminants from drinking water. The identification and quantification of organic contaminants at the nanogran per litre (part‐per‐trillion) level are accomplished by a computerized glass capillary gas chromatography–mass spectrometry system. Applications of closed‐loop‐stripping analysis (CLSA) for monitoring water by water utilities, for studying the use and effects of alternative disinfectants in drinking water, and for providing data on the removal of organic contaminants from water by granular activated carbon (GAC) treatment are discussed. An attempt to validate the method using statistical computations is also included.

Water Quality Characterization—Trace Organics

A need exists for analytical procedures which permit identification and quantification of organic contaminants in aqueous systems in the milligram-per-liter to microgram per liter or lower, concentration range. The Instrumental procedures which are most promising at present involve spectrographic and chromatographic techniques. However, most of these instruments lack the sensitivity to analyze the organic directly at the levels found in natural and waste waters. Preliminary concentration techniques which do not alter either the individual organic constituents or their relative distribution in complex mixture are essential. This review examines typical concentration and analytical procedures indicating sensitivity, limitations, and applications to water technology.