Isolation and preconcentration of volatile organic compounds from water

C itrus monstruosa Discrimination among Several C itrus Species by Multivariate Analysis of Volatiles: A Metabolomic Approach

“…; Namieśnik et al . ) but more recently, the first trapping of head space components followed by thermal desorption, such as for HS‐SPME, was of great interest (Canac‐Arteaga et al . ; Gomes Da Silva and Chaves Das Neves ).…”

“…VOC analysis is traditionally achieved by GC techniques coupled with MS detectors (Tranchida et al 2012) but the critical factor is usually the sampling/extraction step. Several studies report liquid-liquid extraction (Frohlich et al 1989;Namies ´nik et al 1990) but more recently, the first trapping of head space components followed by thermal desorption, such as for HS-SPME, was of great interest (Canac-Arteaga et al 1999;Gomes Da Silva and Chaves Das Neves 1999). In this latter study, in comparison to liquid-liquid extraction, the possible production of artifacts, partial losses of sample during the evaporation step and the sampling time are limited.…”

C itrus monstruosa Discrimination among Several C itrus Species by Multivariate Analysis of Volatiles: A Metabolomic Approach

“…; Namieśnik et al . ) but more recently, the first trapping of head space components followed by thermal desorption, such as for HS‐SPME, was of great interest (Canac‐Arteaga et al . ; Gomes Da Silva and Chaves Das Neves ).…”

“…VOC analysis is traditionally achieved by GC techniques coupled with MS detectors (Tranchida et al 2012) but the critical factor is usually the sampling/extraction step. Several studies report liquid-liquid extraction (Frohlich et al 1989;Namies ´nik et al 1990) but more recently, the first trapping of head space components followed by thermal desorption, such as for HS-SPME, was of great interest (Canac-Arteaga et al 1999;Gomes Da Silva and Chaves Das Neves 1999). In this latter study, in comparison to liquid-liquid extraction, the possible production of artifacts, partial losses of sample during the evaporation step and the sampling time are limited.…”

Design and Evaluation of a New Thermospray Liquid/Liquid Extractor for the Extraction of Semivolatile and Nonvolatile Organic Compounds from Water

“…The effectiveness of the concentration step depends largely on the physical properties of the analytes in the mixture and the nature of the sample matrix. Since chemical equilibrium condition between phases in the concentrator is governed by Henry's law, in K-D concentration, the choice of temperature significantly affects the distribution of the analytes between liquid and vapor phases. Based on U.S. EPA method protocol, the allowable temperature range for methylene chloride reduction in a K-D concentrator is 60−80 °C on a water bath or 35−40 °C for nitrogen evaporation.…”

“…Table lists the recoveries and relative standard deviations of these compounds. Presumably, entrainment of the sample in the solvent vapor during the concentration step, and the temperature or rate at which the concentration step is performed, can lead to loss in sample recovery. , Losses of up to 40% were sustained by many compounds, with more loss and less variability occurring at higher temperatures. Similar losses by K-D concentration have been reported, even for more polar analytes. , Thus, TSLLE was evaluated using high concentrations (low milligrams per liter range) of SVOCs so that direct analysis of the extract was possible without solvent reduction.…”

Prognostic factors for lymphedema after primary treatment of breast carcinoma

“…The bio‐oil (fraction 2) was extracted using standard laboratory liquid–liquid extraction procedures with ethyl acetate 31. 33 All solvents utilized within the proposed methodology were collected and dried on a rotary evaporator to produce another fraction (sugars, fraction 4). It is important to know that the energy efficiency of the process could be substantially improved by using advanced dewatering technology 34…”

C itrus monstruosa Discrimination among Several C itrus Species by Multivariate Analysis of Volatiles: A Metabolomic Approach

“…; Namieśnik et al . ) but more recently, the first trapping of head space components followed by thermal desorption, such as for HS‐SPME, was of great interest (Canac‐Arteaga et al . ; Gomes Da Silva and Chaves Das Neves ).…”

“…VOC analysis is traditionally achieved by GC techniques coupled with MS detectors (Tranchida et al 2012) but the critical factor is usually the sampling/extraction step. Several studies report liquid-liquid extraction (Frohlich et al 1989;Namies ´nik et al 1990) but more recently, the first trapping of head space components followed by thermal desorption, such as for HS-SPME, was of great interest (Canac-Arteaga et al 1999;Gomes Da Silva and Chaves Das Neves 1999). In this latter study, in comparison to liquid-liquid extraction, the possible production of artifacts, partial losses of sample during the evaporation step and the sampling time are limited.…”

Design and Evaluation of a New Thermospray Liquid/Liquid Extractor for the Extraction of Semivolatile and Nonvolatile Organic Compounds from Water

“…The effectiveness of the concentration step depends largely on the physical properties of the analytes in the mixture and the nature of the sample matrix. Since chemical equilibrium condition between phases in the concentrator is governed by Henry's law, in K-D concentration, the choice of temperature significantly affects the distribution of the analytes between liquid and vapor phases. Based on U.S. EPA method protocol, the allowable temperature range for methylene chloride reduction in a K-D concentrator is 60−80 °C on a water bath or 35−40 °C for nitrogen evaporation.…”

“…Table lists the recoveries and relative standard deviations of these compounds. Presumably, entrainment of the sample in the solvent vapor during the concentration step, and the temperature or rate at which the concentration step is performed, can lead to loss in sample recovery. , Losses of up to 40% were sustained by many compounds, with more loss and less variability occurring at higher temperatures. Similar losses by K-D concentration have been reported, even for more polar analytes. , Thus, TSLLE was evaluated using high concentrations (low milligrams per liter range) of SVOCs so that direct analysis of the extract was possible without solvent reduction.…”

Prognostic factors for lymphedema after primary treatment of breast carcinoma

“…The bio‐oil (fraction 2) was extracted using standard laboratory liquid–liquid extraction procedures with ethyl acetate 31. 33 All solvents utilized within the proposed methodology were collected and dried on a rotary evaporator to produce another fraction (sugars, fraction 4). It is important to know that the energy efficiency of the process could be substantially improved by using advanced dewatering technology 34…”

C itrus monstruosa Discrimination among Several C itrus Species by Multivariate Analysis of Volatiles: A Metabolomic Approach

“…; Namieśnik et al . ) but more recently, the first trapping of head space components followed by thermal desorption, such as for HS‐SPME, was of great interest (Canac‐Arteaga et al . ; Gomes Da Silva and Chaves Das Neves ).…”

“…VOC analysis is traditionally achieved by GC techniques coupled with MS detectors (Tranchida et al 2012) but the critical factor is usually the sampling/extraction step. Several studies report liquid-liquid extraction (Frohlich et al 1989;Namies ´nik et al 1990) but more recently, the first trapping of head space components followed by thermal desorption, such as for HS-SPME, was of great interest (Canac-Arteaga et al 1999;Gomes Da Silva and Chaves Das Neves 1999). In this latter study, in comparison to liquid-liquid extraction, the possible production of artifacts, partial losses of sample during the evaporation step and the sampling time are limited.…”

Design and Evaluation of a New Thermospray Liquid/Liquid Extractor for the Extraction of Semivolatile and Nonvolatile Organic Compounds from Water

“…The effectiveness of the concentration step depends largely on the physical properties of the analytes in the mixture and the nature of the sample matrix. Since chemical equilibrium condition between phases in the concentrator is governed by Henry's law, in K-D concentration, the choice of temperature significantly affects the distribution of the analytes between liquid and vapor phases. Based on U.S. EPA method protocol, the allowable temperature range for methylene chloride reduction in a K-D concentrator is 60−80 °C on a water bath or 35−40 °C for nitrogen evaporation.…”

“…Table lists the recoveries and relative standard deviations of these compounds. Presumably, entrainment of the sample in the solvent vapor during the concentration step, and the temperature or rate at which the concentration step is performed, can lead to loss in sample recovery. , Losses of up to 40% were sustained by many compounds, with more loss and less variability occurring at higher temperatures. Similar losses by K-D concentration have been reported, even for more polar analytes. , Thus, TSLLE was evaluated using high concentrations (low milligrams per liter range) of SVOCs so that direct analysis of the extract was possible without solvent reduction.…”

Prognostic factors for lymphedema after primary treatment of breast carcinoma

“…The bio‐oil (fraction 2) was extracted using standard laboratory liquid–liquid extraction procedures with ethyl acetate 31. 33 All solvents utilized within the proposed methodology were collected and dried on a rotary evaporator to produce another fraction (sugars, fraction 4). It is important to know that the energy efficiency of the process could be substantially improved by using advanced dewatering technology 34…”