Sorption Loss Research Articles

Accumulation, Distribution and Metabolism of 14C- 1,1,1- Trichloro-2, 2-, Bis- (P-Chlorophenyl) Ethane (p,p′-DDT) Residues in a Model Tropical Marine Ecosystem

Accumulation, distribution and metabolism of ring labelled, 14C-1,1,1, - trichloro-2,2-bis(p-chlorophenyl)ethane (p,p′-DDT) in a model marine aquatic ecosystem consisting of sea water, sediment, oysters (Isognomonon alatus) and Humbug fish (Dascillus aruanus) were studied in the laboratory. 14C-p,p′-DDT distributes rapidly in the ecosystem immediately after application on the water surface with reduction of its concentration in the water phase from 1.18 ng g−1 to 0.71 ng g−1 after 2 hours and an increase in its content in the sediment and oysters. The bioconcentration factor reached a maximum of 19× 103 in oysters, and 1657 in Humbug fish after 24 hours. The sediment concentration reached 117 ng g−1 after 168 hours from start of application. A peak bioconcentration factor of 111 × 103 was calculated after 120 hours when 0.24 mg kg−1 of 14C-p,p′-DDT was maintained through dosing every 24 hours with 0.002 mg kg−1 of a mixture of labelled and non-labelled pesticide. The rate of depuration of accumulated 14C-p,p′-DDT sediment residues was up to 78.3% after 24 hours while oysters lost only 14.0% during the same period. The loss in Humbug fish was only 22.2% in three days. Volatilisation and sorption losses from seawater alone (without sediment/biota) were found to be very high in the range of 73.8 – 91.5% over 24 h for p,p′-DDT in aerated and non-aerated ecosystem. Gas chromatograph and TLC analysis of water, sediment and oyster samples revealed presence of p,p′-DDT and substantial amounts of p,p′-DDE and p,p′-DDD three days after pesticide dosage.

Gas-phase organics in environmental tobacco smoke. 1. Effects of smoking rate, ventilation, and furnishing level on emission factors.

We measured the emissions of 26 gas-phase organic compounds in environmental tobacco smoke (ETS) using a model room that simulates realistic conditions in residences and offices. Exposure-relevant emission factors (EREFs), which include the effects of sorption and re-emission over a 24-h period, were calculated by mass balance from measured compound concentrations and chamber ventilation rates in a 50-m3 room constructed and furnished with typical materials. Experiments were conducted at three smoking rates (5, 10, and 20 cigarettes day(-1)), three ventilation rates (0.3, 0.6, and 2 h(-1)), and three furnishing levels (wallboard with aluminum flooring, wallboard with carpet, and full furnishings). Smoking rate did not affect EREFs, suggesting that sorption was linearly related to gas-phase concentration. Furnishing level and ventilation rate in the model room had little effect on EREFs of several ETS compounds including 1,3-butadiene, acrolein, acrylonitrile, benzene, toluene, and styrene. However, sorptive losses at low ventilation with full furnishings reduced EREFs for the ETS tracers nicotine and 3-ethenylpyridine by as much as 90 and 65% as compared to high ventilation, wallboard/aluminum experiments. Likewise, sorptive losses were 40-70% for phenol, cresols, naphthalene, and methylnaphthalenes. Sorption persisted for many compounds; for example, almost all of the sorbed nicotine and most of the sorbed cresol remained sorbed 3 days after smoking. EREFs can be used in models and with ETS tracer-based methods to refine and improve estimates of exposures to ETS constituents.

Observation of sorptive losses of volatile sulfur compounds during natural gas sampling

The reason for the compound-dependent over-estimation of the recoveries of several volatile organic sulfur compounds when using a Silcosteel cylinder for sample storage as reported earlier was examined. From the different possible sources of errors that were taken into consideration, the silicone tubing, which was used to fill a standard Tedlar sample bag for calibration, was identified as the cause of the artefact. The comparison of different tubing materials showed that PTFE is the best choice since it causes only minor losses (<10%) of propyl- and butylmercaptans.

Isolation of colloidal monomethyl mercury in natural waters using cross-flow ultrafiltration techniques

A series of experiments was conducted to evaluate the appropriateness of cross-flow ultrafiltration (CFUF) techniques for the determination of the phase speciation of monomethyl mercury (MeHg) in natural waters. Spiral-wound cartridge (Amicon S1Y1) and Miniplate (Amicon) were evaluated for their nominal molecular weight cut-offs of 1 and 10 kDa, respectively. The ultrafiltration behavior of standard macromolecules showed that the permeation of high molecular weight (HMW) organic macromolecules was not significant when a concentration factor (CF)>15 was used. The retention of low molecular weight (LMW) molecules was significant, especially at a low CF<5, suggesting that the use of a high CF (∼15) will minimize the retention of LMW molecules. Sorptive losses of MeHg in the solution phase to the 1 kDa membrane were negligible, but MeHg bound to HMW macromolecules was still retained (∼20%), even with a preconditioned membrane. The mass balance recovery of MeHg during ultrafiltration averaged 101±15% (n=7) and 105±14% (n=5) for the 1 and 10 kDa membranes, respectively. Sample storage over 24 h caused significant coagulation (∼47%) of the <10 kDa MeHg into the 10 kDa–0.45 μm colloidal or the particulate MeHg pool. The 1 kDa–0.45 μm colloidal MeHg in Galveston Bay and the Trinity River water samples accounted for 40–48% of the filter-passing MeHg, although the most abundant fraction (52–60%) of MeHg was the truly dissolved fraction (<1 kDa). The partition coefficient between the colloidal (1 kDa–0.45 μm) and truly dissolved MeHg (average log K C =5.2) was higher than the partition coefficient based on particle/filter-passing (average log K D =4.6) or particle/truly dissolved MeHg (average log K P =4.8), suggesting that MeHg has stronger affinity for natural colloids than macroparticulate materials (>0.45 μm).

A review of in situ measurement of organic compound transformation in groundwater.

Laboratory assessments of the rate of degradation of organic compounds in groundwater have been criticized for producing unrepresentative results. The potential for organic compounds to be transformed in groundwater has been measured using in situ methods, which avoid problems of attempting to duplicate aquifer conditions in the laboratory. In situ assessments of transformation rates have been accomplished using transport studies and in situ microcosms (ISMs); a review of these methods is given here. In transport studies, organic solutes are injected into an aquifer and the concentrations are monitored as they are transported downgradient. The change in mass of a solute is determined by the area contained under the breakthrough curve (plot of concentration versus time). ISMs isolate a portion of the aquifer from advective flow and act as in situ batch reactors. Experiments using ISMs involve removing water from the ISM, amending it with the solutes of interest, re-injecting the amended water, and monitoring the solute concentrations with time. In both transport and ISM studies, the loss of organic solutes from solution does not allow a distinction to be made between sorptive, abiotic and biotic transformation losses. Biological activity can be chemically suppressed in ISMs and the results from those experiments used to indicate sorption and abiotic loss. Transformation products may be monitored to provide additional information on transformation mechanisms and rates.

Characteristics of sorption losses of polychlorinated biphenyl congeners onto glass surfaces

Sorption losses to glass surfaces of five polychlorinated biphenyl (PCB) congeners in aqueous solutions were investigated. Adsorption/desorption experiments were conducted under conditions that simulated actual sample handling procedures for environmental samples. It was found that the adsorption loss is related to the degree of chlorination. PCB congener 180 lost the most onto glass surfaces, followed by congeners 138, 101/28, and 52, in decreasing order. More PCB adsorption occurred onto glass under conditions of agitation and higher temperature (22°C) during the five-day experimental period. The salinity effect (“salting out effect”) was also observed in this work. The efficiency of desorption (rinsing three times with solvent) was found to be ineffective in extracting adsorbed PCBs. It was necessary to use mechanical shaking for extraction. Storage of samples up to five days resulted in sorption losses as much as 30%, 17%, 30%, 40%, and 55% of PCB 28, 52, 101, 138, and 180, respectively. Sorption losses need to be considered when conducting water sampling or toxicological studies to avoid underestimation of the actual PCB concentrations and their toxic effects.

Coating effects on the glass adsorption of polychlorinated biphenyl (PCB) congeners

The effects of coating materials on polychlorinated biphenyl (PCB) adsorption in aqueous solution were assessed in an attempt to minimize PCB sorption loss during sampling processes. A coating material, which enhances PCB adsorption and allows adsorbed PCBs to be readily extracted by solvents, can act as a sampling concentrator to reduce PCB losses from both adsorption and evaporation. Several coating materials were evaluated, including paraffin oil, silicone oil, dimethyldichlorosilane (Sylon-CT), Prosil 28 ® and polydimethylsiloxane (PDS) with viscosity 0.65, 50 (PDS 50), and 500 (PDS 500) cSt. PDS and silicone oil enhanced adsorption for all five congeners examined (IUPAC No. 28, 52, 101, 138, and 180). Sylon-CT, paraffin oil and Prosil 28 ® had inconsistent effects on adsorption of different congeners. Desorption of adsorbed PCBs onto all coating types was assessed. The recovery efficiency of extracting PCBs with solvents was enhanced greatly with all coatings as opposed to non-coated surfaces, with the exception of paraffin oil. Coating with silicon oil, PDS 50, and 500 resulted in virtually 100% recovery of adsorbed PCBs. It was also found that Teflon containers were poor substitutes for glass containers and failed to minimize PCB losses. Among the materials studied, the best coating that could be used as a sampling concentrator was PDS 500.

A Critical Evaluation of Tangential-Flow Ultrafiltration for Trace Metal Studies in Freshwater Systems. 2. Total Mercury and Methylmercury

Laboratory and field investigations of 10 kDa polyethersulfone (PES) and regenerated cellulose (RCL) membranes were conducted to evaluate the utility of ultrafiltration (UF) for low-level mercury determinations in freshwaters. Laboratory investigations focused on blank levels, sorption loss, and charge rejection; while field investigations addressed mass balance closure, replicate precision, and permeate trends in concentration. A thorough mass balance approach was used throughout the investigation, and experiments were conducted across typical gradients in freshwater pH, specific conductance, and dissolved organic carbon (DOC). The minimum source-water HgT concentration that could be confidently processed from a 5 L volume was 0.5 ng L-1 for PES and 1.4 ng L-1 for RCL as determined by three times the standard deviation of our method blank. The minimum source-water MeHg concentration was 0.5 ng L-1 for PES and 0.2 ng L-1 for RCL based on river-water mass balance results. Mass balance closures were generally better for RCL than PES, especially for MeHg where 95% of the residuals (n = 21) were within ±30% of closure. Duplicate UF separations on RCL membranes, and between RCL and PES membranes, agreed within 16% in the colloidal and dissolved fractions for both total mercury (HgT) and MeHg. Mercury sorption loss and charge rejection were greater for PES membranes than RCL membranes, especially for low ionic strength waters (<100 μS cm-1). Increases in permeate concentration were observed as the UF separation progressed, and preconditioning the membrane with a subsample of the feed solution did not substantially improve the performance. Overall, RCL outperformed PES membranes in low ionic strength waters and therefore is preferred for investigations of mercury partitioning under ambient freshwater conditions.

A Critical Evaluation of Tangential-Flow Ultrafiltration for Trace Metal Studies in Freshwater Systems. 1. Organic Carbon

The utility of tangential flow ultrafiltration (TFUF) for size fractionation of natural organic matter (NOM) in freshwater streams was investigated, focusing on characterization or elimination of potential artifacts. Spiral-wound polyethersulfone (PES) and regenerated cellulose (RCL) membranes with nominal molecular weight limits of 10 kilodalton (kDa) and 100 kDa were compared as part of a large project assessing the utility of large volume (>5 L) ultrafiltration for determining trace metal speciation in freshwaters. With careful cleaning, reliable fractionations of carbon and trace metals in freshwater can be obtained, and a detailed protocol necessary to avoid potentially significant biases is presented. Both PES and RCL membranes can be cleaned efficiently to provide low carbon blanks (<0.03 mg C L-1) and recleaned at least 10 times without compromising membrane integrity. For RCL, residual acid from the cleaning procedure can lower the permeate pH to below 4 in low-alkalinity river samples, but this acid can be removed prior to sample filtration with a simple treatment. Mass balance experiments with stream NOM show good recovery (99.7% ± 9.5%, n = 67). Sorption losses are very low (on average, <2%) to RCL membranes but are higher for PES. Replicate precision is typically better than ±5% for carbon. There are significant differences between PES and RCL membranes: permeate carbon levels are similar, but RCL predicts a larger >10 kDa fraction and carbon sorption is more significant on PES. These findings could be explained by greater hydrophobic interactions of dissolved organic carbon with PES and charge interactions with RCL. A strong negative correlation is observed between the percent of colloidal carbon (10 kDa − 0.4 μm) and the log specific conductance of streamwaters (R 2 = 0.71).

Re-examination of cross-flow ultrafiltration for sampling aquatic colloids: evidence from molecular probes

Application of cross-flow ultrafiltration techniques to marine systems has greatly increased in recent years. However, the retention and permeation behavior of macromolecules and their associated trace elements during ultrafiltration is still . controversial. In addition, the optimum concentration factor CF and the possibility for a ''breakthrough'' of high molecular . . weight HMW dissolved organic carbon DOC during ultrafiltration are still a matter of contention. The permeation and retention behavior of natural DOC, standard macromolecules and selected metals was examined on a 1 kDa Amicon S10N1 ultrafiltration cartridge, using molecular probes and radioactive metals spiked to natural seawater. Laboratory results from . . molecular probes show that significant fractions ) 40% of low molecular weight LMW molecules 0.5 kDa rhodamine . 6G and 0.6 kDa glutathione are retained by a 1 kDa ultrafilter membrane, even under a CF of ; 50. Therefore, the retention of LMW molecules can give rise to an overestimate of the colloidal fraction, especially under lower CFs. The percentage of HMW molecules passing through the 1 kDa membrane decreases rapidly with increasing size or MW. On . average, ; 15% of vitamin B 1.3 kDa and ; 3% of a 3 kDa dextran pass through the 1 kDa membrane. However, 12 . permeation of a 10 kDa dextran through the 1 kDa membrane becomes negligible - 0.6% . Thus, the permeation of HMW molecules is minimal during ultrafiltration, even under high CFs. The ultrafiltration behavior of natural DOC and LMW metals can be well predicted by a permeation model, and consistently shows an increasing concentration in the permeate with increasing CFs. Standard dextrans, rhodamine 6G and natural DOC are recovered at 92-95%, while losses of glutathione and vitamin B to the membrane can be significant. Possible sorptive losses and overall mass balance of 12 molecules are thus dominated by their physicochemical properties but not by their MWs. Most retained LMW DOC can be further removed during diafiltration whereas loss of HMW DOC during diafiltration is minimal. Since retention of LMW .

Estimating Diffusion Coefficients in Low-Permeability Porous Media Using a Macropore Column

Diffusion coefficients in an aquitard material were measured by conducting miscible solute transport experiments through a specially constructed macropore column. Stainless steel HPLC columns were prepared in a manner that created an annular region of repacked aquitard material and a central core of medium-grained quartz sand. The column transport approach minimizes volatilization and sorption losses that can be problematic when measuring hydrophobic organic chemical diffusion with diffusion-cell methods or column-sectioning techniques. In the transport experiments, solutes (tritiated water, 1,2,4-trichlorobenzene, and tetrachloroethene) were transported through the central core by convection and hydrodynamic dispersion and through the low-permeability annulus by radial diffusion. All transport parameters were independently measured except for the effective diffusion coefficient in the aquitard material, which was obtained by model fitting. Batch-determined retardation factors agreed very closely with mom...

Isolation and analysis of lignin-derived phenols in aquatic humic substances: improvements on the procedures

Procedures for the extraction of aquatic humic substances and analysis of their lignin-derived phenols were assessed and altered to simplify and shorten XAD-8 resin cleaning, reduce losses due to sorption, and optimize oxidative release of phenols without increasing their transformation. The revised cleaning procedures require 5 rather than 120 h and sorptive losses of humic acids were reduced 7%. Coefficients of variation for individual phenols in the final method ranged from 1 to 11%. The method was used to analyze lignin-derived phenols in White Clay Creek watershed humics, Suwannee River humics (IHSS), and Lake Washington sediments.

Rapid loss of fentanyl citrate admixed with fluorouracil in polyvinyl chloride containers.

To study the physical compatibility and chemical stability of fluorouracil 1 and 16 mg/mL with fentanyl citrate 12.5 micrograms/mL in dextrose 5% and in sodium chloride 0.9% injection. Test solutions of the drugs in dextrose 5% injection and in sodium chloride 0.9% injection were prepared in triplicate and stored at -20, 4, 23, and 32 degrees C. Samples were removed immediately and at various times over 7 days and stored at -70 degrees C until analyzed. Physical compatibility was assessed visually and by measuring turbidity with a color-correcting turbidimeter; particle content was measured with a light-obscuration particle sizer and counter. Chemical stability was determined by measuring the concentration of each drug in the test solutions in duplicate with stability-indicating HPLC. Fentanyl citrate was rapidly lost when admixed with fluorouracil in polyvinyl chloride (PVC) containers, losing about 25% in the first 15 minutes and about 50% in the first hour. The loss of fentanyl citrate was so rapid that accurate time zero determinations were not possible. The extent of fentanyl loss increased with time and occurred more rapidly at the higher temperatures (i.e., 23, 32 degrees C). Losses of 70% or more occurred in all samples within 24 hours. Fentanyl underwent rapid sorption to the containers at the high pH (9.0-9.5) of the fluorouracil admixtures. Adjusting the pH of a fentanyl citrate solution (containing no fluorouracil) in PVC containers to pH 9 with sodium hydroxide also resulted in rapid sorption loss. Fentanyl citrate sorption did not occur when admixtures were prepared in polyethylene containers. Fluorouracil remained stable for at least 7 days at all temperatures. There were no visual or subvisual changes in turbidity or particle content in any of the test solutions at any time. When admixed with fluorouracil 1 and 16 mg/mL in dextrose 5% injection and sodium chloride 0.9% injection, fentanyl citrate 12.5 micrograms/mL underwent rapid and extensive loss due to sorption to the PVC containers, making the combination unacceptable within minutes of mixing. The sorption results from the alkaline pH of the admixture and, presumably, could occur from the admixture of fentanyl citrate with any sufficiently alkaline drug.

Evaluation of a Continuous Composite Sampler for Volatile Organic Compounds in Water

The high volatility and low water solubility of volatile organic compounds (VOCs), make the collection of representative samples difficult. The standard grab sampling method only gives information of that moment in time when the sample is taken. When the composition of VOCs is varying, continuous composite sampling will give a more representative sample. However, no thorough evaluation of its use for VOCs has been reported. The use of an automatic continuous composite sampler for the analysis of VOCs in water was studied. The causes and magnitude of the VOCs losses during the sampling process were determined. Adsorbent cartridges were used to trap the VOCs escaping from solution during the sampling process. Sorption phenomena occurring on the containers and/or tubings were also evaluated. Sorption losses were much more significant than volatilization losses. The results indicate that a modified version of this sampler can be an alternative for the long term sampling of water for VOC analysis.

Interaction of food packaging material and selected food components under high pressure

Abstract Interactions between ethanolic solutions of p-cymene and acetophenone and different polymer packaging materials. were studied at 500 MPa and 25° C. p-Cymene solution, filled into low-density polyethylene bags, lost 30% of its aroma concentration after 24 h at 500 MPa compared to a 60% loss at atmospheric pressure. The decrease was strongest within the first 15 min. Using LDPE/HDPE/LDPE bags, losses were 20% and 30%, resp. Applying the “bag in the bag” method, p-cymene concentrations measured inside and outside the inner bag has shown sorption by the pressurized film to be one third of that by the non-pressurized. In PET/AI/LDPE bags impermeable to p-cymene, sorption was confined to the inner LDPE layer and caused higher loss in the non-pressurized sample. Acetophenone has not been found to interact with the polymer during pressure treatment, while at atmospheric pressure sorption loss in aroma concentration was nearly 70% after 60 h.

Activity of urokinase diluted in 0.9% sodium chloride injection or 5% dextrose injection and stored in glass or plastic syringes

The effects of the diluent, the container, the i.v. set, and the drug concentration on the adsorption of urokinase to i.v. administration systems were studied, along with the compatibility of urokinase with plastic and glass syringes. Solutions of urokinase 1500 and 5000 IU/mL in 0.9% sodium chloride injection and 5% dextrose injection in glass and polyvinyl chloride (PVC) containers were sampled at 2 and 30 minutes. Administration sets were attached to PVC containers containing the urokinase-5% dextrose injection solutions, and samples were collected at 90 and 150 minutes. Glass and polypropylene syringes containing urokinase 5000 IU/mL in 0.9% sodium chloride injection or 5% dextrose injection were sampled at 0, 4, 8, and 24 hours. Urokinase activity was measured by an in vitro clot lysis assay. No urokinase diluted in 0.9% sodium chloride injection adsorbed to glass or PVC containers. For urokinase 1500 IU/mL in 5% dextrose injection, a loss of 15% to 20% occurred almost instantaneously in PVC containers; additional losses to the infusion sets were minimal. However, for urokinase 5000 IU/mL in 5% dextrose injection, no losses were observed in the PVC systems. No drug loss to glass bottles was seen for urokinase 1500 or 5000 IU/mL in 5% dextrose injection. Urokinase potency remained constant in polypropylene and glass syringes for 24 hours. To minimize urokinase sorption to PVC containers, higher concentrations of urokinase diluted in 5% dextrose injection should be used, provided that clinical safety and efficacy are not compromised. The use of 0.9% sodium chloride injection as a diluent also prevents sorption losses.

Evaluation of disposable membrane filter units for sorptive losses and sample contamination

Abstract Nine disposable 0.4‐ to 0.5‐μm filter, units were tested for sample contamination from aqueous matrices. For some types of filters, contamination and sorptive losses ware significant. Degree of sorptive loss was a function of volume filtered and filtration rate. Analyte sorption was found to be reversible and could be mitigated by the addition of methanol (1/1 V/V) as an organic modifier prior to filtration.

Adsorption of platinum, gold and silver by filter paper and borosilicate glass and its relevance to biogeochemical studies

Platinum, gold and silver are lost from solution by the filtration procedure usually followed in the pre-analytical treatment of resuspended ashed or acid-digested plant tissues. Sorption losses however, may be reduced by the presence of other cations in the filtrate. Low concentration gold solutions (1–10 ng ml −1) cannot be stored in borosilicate glass containers for more than 48 hours, even with acidification. Synthetic solution data from this study suggest that some published values for these precious metals may have underestimated plant tissue concentrations.

Modification of centrifugal filtration device for elimination of sorption losses

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTModification of centrifugal filtration device for elimination of sorption lossesWilliam A. MacCrehanCite this: Anal. Chem. 1982, 54, 4, 838–839Publication Date (Print):April 1, 1982Publication History Published online1 May 2002Published inissue 1 April 1982https://doi.org/10.1021/ac00241a064RIGHTS & PERMISSIONSArticle Views30Altmetric-Citations4LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (258 KB) Get e-Alerts Get e-Alerts

Conserveermiddelen en oogdruppelverpakking

Of the common eye drop preservatives benzalkonium chloride, phenylmercuric borate, chlorhexidine digluconate and phenylethanol, sorption losses were determined which occurred at contact with rubber or plastics of commercially available eye drop bottles. Of all tested materials only chlorbutyl rubber and polypropylene did not sorb detectable amounts of the preservatives.