Analyses of Procymidone and Vinclozolin in Greenhouse Air

Abstract

A method for sampling and analysis of procymidone and vinclozolin in greenhouse air was investigated. The behaviour of Chromosorb 102, Porapak R, Supelpak-2, Amberlite XAD-2, Amberlite XAD-4 and polyurethane foam (PUF) as sorbents was studied. Atmospheres containing known concentrations of these pesticides were generated. The desorption process of the analytes, concentration step and behaviour of sorbents in air with different relative humidities were tested. No breakthrough was observed in the range of concentrations studied.

Personal samplers were used with the selected sorbent (PUF), for sampling procymidone and vinclozolin in an experimental greenhouse. GC-ECD analysis and MS confirmation were performed. The dissipation process of the analytes in the 24 h period after application was studied.     

Automatic flow system for evaluation of polystyrene-divinylbenzene sorbents applied to preconcentration of phenolic pollutants

In this work, an evaluation of commercially available polystyrene-divinylbenzene sorbents for solid-phase extraction (SPE) of eleven phenolic compounds is intended. Considering the particle size and cross-linking degree, Amberlite XAD-4 (commercial or grounded), Macronet MN-200 and Lichrolut EN were tested. The SPE protocol was performed by an automatic system, providing repeatable experimental conditions for assessment of sorbent capacity, breakthrough volume and enrichment factor (EF). A positive correlation between EF and log?K _ow was found for Amberlite XAD-4 while a negative correlation was observed between EF and molecular weight of analyte for Macronet MN-200 and for Lichrolut EN. This indicates a prevalence of hydrophobic interactions or molecular exclusion depending upon the polymer cross-linking degree. Despite the similar repeatability (RSD?<?4.7%, n?>?6) and recovery values attained (97.6–102.7%, using 50?mL of sample) for all sorbents, Lichrolut EN is the best choice for analytical application as higher EF and lower LOD values (between 18 and 207?ng) were attained for this sorbent.     

1H NMR cryoporosimetry of swollen hypercrosslinked polymers

The porous structure of two laboratory samples of hypercrosslinked polystyrene networks with a crosslinking degree of 200%, the commercial hypercrosslinked sorbent MN-270 (Purolite Int.), and macroporous polystyrene sorbents Amberlite XAD-4 and Amberlite XAD-1600 were investigated by means of ¹H NMR cryoporosimetry. It was determined that the signal intensity of benzol, dioxane, dichloroethane and water protons previously frozen in polymer pores increases during solvent melt. Dependencies of the integral proton signal intensities on the sample temperature obtained in various solvents are discussed in terms of sample micropore accessibility and solvent—polystyrene interaction energy. Pore dimensions are estimated using the melting temperature value of ice according to the Gibbs—Thomson equation. We conclude that the obtained distribution curves reveal all hypercrosslinked polymers to be mainly microporous with diameter distribution maxima around 10 Å. It is shown that along with pores 120 Å in diameter, XAD-4 has a considerable amount of micropores. In contrast, XAD-1600 is ranged as a mesoporous sorbent.     

Sorbents based on calix[4]arenes for extraction of technetium(vii) from acidic and alkaline media

Sorption of Tc^VII from solutions of various compositions with new sorbents prepared by the noncovalent immobilization of (thia)calix[4]arenes on the Amberlite XAD-7™ support was studied. The sorbents studied efficiently extract technetium(vii) from both acidic and alkaline media. The sorption capacity of the sorbent with thiacalix[4]arene groups is superior to that of the sorbents with calix[4]arene groups and several times higher than that of the sorbents previously proposed for the sorption of Tc^VII. Technetium(vii) is sorbed by this sorbent as 1: 1 and 1: 2 thiacalix[4]arene—NH₄TcO₄ and 1: 1 and 1: 2 thiacalix[4]arene—NaTcO₄ complexes.     

Determination of imidacloprid and its metabolite 6-chloronicotinic acid in greenhouse air by high-performance liquid chromatography with diode-array detection

A method is described for analysing and sampling imidacloprid and its metabolite 6-chloronicotinic acid in greenhouse air by high-performance liquid chromatography (HPLC) with diode-array detection (DAD). The trapping efficiency of two solid sorbents, Amberlite XAD-2 and Amberlite XAD-4 and the use of different desorption procedures have been tested. To validate the methodology, standard atmospheres containing known concentrations of these pesticides and with different relative humidities were generated. No breakthrough was observed in the range of concentrations studied. Dissipation of analytes was investigated in a 24 h period after application by using personal samplers in a field experiment.     

Determination of polychlorinated biphenyl compounds in indoor air samples

A simple procedure for the determination of six non-coplanar polychlorinated biphenyls (PCBs) in medium volumes of indoor air is described. Samples are forced at 6 m3/h through a device consisting of a quartz filter connected to the end of a conventional solid-phase extraction cartridge containing 60 mg of functionalized styrene-divinylbenzene. PCBs retained on the sorbent are directly eluted with 2 ml of hexane. Those associated to airborne particulate matter are microwave extracted in 10 min using 15 ml hexane-acetone (1:1). The proposed procedure is favorably compared to the use of polyurethane cylinders for the concentration of PCBs in terms of solvent consumption and rapidity of the desorption step. Furthermore, the functionalized sorbent showed higher breakthrough volumes than Amberlite XAD-2 for PCBs in gas phase. Quantification limits between 2 and 40 pg/m3 were obtained for six PCBs (from di- to heptachlorobiphenyls) using GC-electron-capture detection.     

Sorbent-based sampling methods for volatile and semi-volatile organic compounds in air. Part 2. Sorbent selection and other aspects of optimizing air monitoring methods

Sorbent tubes/traps are widely used in combination with gas chromatographic (GC) analytical methods to monitor the vapour-phase fraction of organic compounds in air. Applications range from atmospheric research and ambient air monitoring (indoor and outdoor) to occupational hygiene (personal exposure assessment) and measuring chemical emission levels. Part 1 of this paper reviewed the main sorbent-based air sampling strategies including active (pumped) tube monitoring, diffusive (passive) sampling onto sorbent tubes/cartridges plus sorbent trapping/focusing of whole air samples that are either collected in containers (such as canisters or bags) or monitored online. Options for subsequent extraction and transfer to GC(MS) analysis were also summarised and the trend to thermal desorption (TD)-based methods and away from solvent extraction was explained. As a result of this trend, demand for TD-compatible sorbents (alternatives to traditional charcoal) is growing. Part 2 of this paper therefore continues with a summary of TD-compatible sorbents, their respective advantages and limitations and considerations for sorbent selection. Other analytical considerations for optimizing sorbent-based air monitoring methods are also discussed together with recent technical developments and sampling accessories which have extended the application range of sorbent trapping technology generally.     

Selection of sampling adsorbents and optimisation and validation of a GC-MS/MS method for airborne pesticides

A methodology for the sampling and determination of airborne pesticides has been developed. The trapping efficiency of three adsorbents, namely XAD-2,XAD-4 and a sandwich sorbent (PUF-XAD2-PUF), was tested for 34 pesticides and the latter was selected because it presented the highest retention capacity without breakthrough. Pesticides were determined by gas chromatography coupled to an ion trap mass spectrometer in tandem. The method showed recoveries ranging from 70% to 120% with limits of quantification in the range of 16.1–322.6 pg m^?3 when 155 m³ were sampled. This analytical strategy was applied to 10 indoor air samples collected in dwellings from the Valencian Region. Six pesticides, namely diphenylamine, pyrimethanil, bifenthrin, lambda-cyhalothrin, permethrin and cypermethrin were detected in indoor samples with concentrations ranging from 1.46 to 22.02 ng m^?3.     

Flame AAS determination of lead in water with flow-injection preconcentration and speciation using functionalized cellulose sorbent

The on-line solid phase extraction of trace amount of lead in flow-injection system with flame AAS detection was investigated using cellulose sorbents with phosphonic acid and carboxymethyl groups, C(18) sorbent non-modified and modified with Pyrocatechol Violet or 8-quinolinol, commercial chelating sorbents Chelex 100 and Spheron Oxin 1000, non-polar sorbent Amberlite XAD-2 modified with Pyrocatechol Violet and several cation-exchange resins. The best dynamic characteristics of retention were observed for functionalized cellulose sorbents. For Cellex P assumed as optimum sorbent, elution with a separate fractions of nitric acid and ethanol allows the differentiation between tetraalkyllead and sum of inorganic lead and organolead species of smaller number of alkyl groups. The detection limit for the determination of inorganic Pb(II) was estimated as 0.17 microg/l. at preconcentration from 50 ml sample at a flow rate of 7 ml/min.     

High-volume sampling of airborne polychlorobiphenyls with amberlite xad-2 resin

Polyurethane foam, polyurethane foam coated with DC-200, Florisil, and Amberlite XAD-2 resin have been evaluated in a small-scale comparative study of their ability to sample airborne polychlorobiphenyls. XAD-2 resin has an excellent collection efficiency for tetrachlorobiphenyl at 1 l min^-1 flow rates and is also suitable for high-volume air sampling. A high-volume air sampler was modified to sample both particulate and vapor-phase polychlorobiphenyls by incorporating the XAD-2 resin behind a glass fiber filter. When the sampling system was operated at a flow rate of 0.7 m³ min^-1 for 24 h, the collection efficiencies for tetrachlorobiphenyl and Aroclor 1221 were 96.5% and 83.0%, respectively.     

Sorption–Spectroscopic Determination of Phosphates in Waters as Molybdenum Heteropoly Acids

Conditions have been found for the preconcentration and reduction of molybdophosphoric acid from aqueous solutions on Amberlite XAD-7 and XAD-8 adsorbents in the batch and dynamic modes. A spectrophotometric method was developed for determining phosphate as molybdophosphoric acid after its extraction on Amberlite XAD-8 and desorption with acetonitrile. The concentration factor was 5.0 × 10³. A sorption–spectroscopic method was also proposed for determining phosphate in solutions as molybdovanadophosphoric acid, one which includes its adsorption on polyurethane foam, reduction in the sorbent phase, and the measurement of diffuse reflectance.     

Application of tryptamine as a derivatizing agent for the determination of airborne isocyanates. Part 5. Investigation of tryptamine-coated XAD-2 personal sampler for airborne isocyanates in workplaces.

The development of an efficient solid sorbent personal sampler with increased convenience for sample collection in workplaces is described. Several solid sorbents were coated with tryptamine, and sampling tubes were prepared with the coated sorbents. These tubes were evaluated for the collection of phenyl isocyanate vapour generated in a commercial test atmosphere generation system that permits the simultaneous collection of up to 12 uniformly loaded samples. Tryptamine-coated XAD-2 resin was shown to be the most efficient solid sorbent for the collection of airborne phenyl isocyanate. The optimum amount of tryptamine needed for coating XAD-2 resin was investigated.     

Comparison of sampling efficiency and storage stability on different sorbents for determination of solvents in occupational air

This study describes the sampling efficiency and storage stability of compounds typically present in occupational atmospheres on the sorbents Anasorb CSC, Anasorb 747, and Chromosorb 106. The selection of compounds included in the study contained aliphatic and aromatic hydrocarbons, alcohols, esters, glycol ethers, ketones, and halogenated compounds, thus representing a wide range of chemical and physical properties. The different sorbent tubes were simultaneously exposed to the selected compounds as three different mixtures of solvent vapours in air, and storage both at room temperature and at -22 degrees C was investigated. The sorbent tubes were stored and analyzed at two different laboratories. The sampling efficiencies of all the investigated compounds were excellent on Anasorb CSC and Anasorb 747, while Chromosorb 106 did not give such good results for the most volatile compounds under study. The room temperature storage stability on Chromosorb 106, however, was good for all compounds, although formation of artefacts was observed during storage, a disadvantage that was substantially reduced by storage at -22 degrees C. The room temperature storage stability on Anasorb CSC was good for all compounds except some of the ketones. The room temperature storage stability of these ketones, especially cyclohexanone and 2-butanone, was much better on Anasorb 747, which still showed the same excellent storage stability for the remaining compounds. When stored in a freezer, the storage stability of all compounds, including the ketones, was very good on all sorbents. Among the sorbents under study, Anasorb 747 appears to be the most suitable all-round sorbent for monitoring volatile compounds in occupational air, with satisfactory capabilities regarding both sampling efficiency and storage stability.     

Fixation of XAD-4 power on filter paper using methyl cellulose for the passive air sampling of semi-volatile organic compounds in indoor air

The sorption capacity of a substrate serving as sampling medium can be enhanced by adding another sorbent to its surface. This is usually achieved through an impregnation process by repeated dipping of the substrate in a slurry solution containing the powder of the sorbent. Because the impregnation process only deposits the sorbent powder on the surface of the substrate, the powder could detach and fall off during field deployment. In this study, a novel approach was explored to fix the added sorbent powder to the surface of the substrate. Methylcellulose (MC) in fine crystal form was selected as the fixing agent to secure the powder of polystyrene-divinyl benzene copolymer resin (XAD-4), with its high sorption capacity, to a cellulose filter paper (CFP). The process involved first mixing XAD-4 and MC in the presence of water to form a milky slurry solution that was then painted on to the surface of the paper and then allowed to dry. The painting technique resulted in a good reproducibility of the applied amount of XAD-MC mixture with a relative standard deviation (RSD) of 12% (n = 5). Scanning electron microscope (SEM) images showed that the XAD-4 powder was held to the surface of the filter paper. No free XAD powder was dislodged from the coated filter paper when coated paper was flicked with a finger. For use as an indoor passive air sampler (PAS), this new sampling medium was placed in a round housing made of electronically polished aluminium material and was tested for uptake of polybrominated diphenyl ethers and phthalic acid dialkylesters. Surface area specific uptake rates (ASUR) of PBDEs ranged from 1.14 to 2.82 m³/(dm²d), while ASUR of phthalates had a wider range from 2.74 to 5.66 m³/(dm²d).     

Determination of nitrogen trichloride (NCl3) levels in the air of indoor chlorinated swimming pools: an impinger method proposal

The quality of the environmental air from indoor swimming pools has been associated with various health risks. Particular attention has focused on the effects of chronic lung exposure to chlorine and its by-products, especially in young children. We developed a simple, non-toxic approach to detect and monitor nitrogen trichloride air levels in the indoor swimming pool environment. The proposed Impinger Method (IM) was used to measure the environmental levels of nitrogen trichloride (NCl₃) in 17 indoor swimming pools located in Northern Italy. This new analytical protocol is based on a colorimetric reaction commonly employed to detect the total and free chlorine levels in water. Specifically, IM allows the entrapment of NCl₃ into a water solution containing diethyl-p-phenylenediamine (DPD 1) and Potassium Iodide (DPD 3). NCl₃ from the air environment reacts with DPD 3 releasing iodine, which reacts with DPD 1 and produces a coloration proportional to the amount of NCl₃ from the sampled indoor swimming pool air. Our sampling of the monitored swimming pool environments evidenced a mean NCl₃ level (637?±?220?µg/m³) higher than the recommended WHO value (500?µg/m³). The IM was validated in terms of linearity (R ^2?=?0.996), limit of detection (3.6?µg/m³) and repeatability (CV?=?1.7%), demonstrating easy-to-use characteristics, good efficiency and low cost.     

Aluminium determination in environmental samples by graphite furnace atomic absorption spectrometry after solid phase extraction on Amberlite XAD-1180/pyrocatechol violet chelating resin

A chelating resin, pyrocatechol violet (PV) immobilised on an Amberlite XAD-1180 support, was prepared and its use for the atomic absorption spectrometric determination of aluminium was investigated. The XAD-1180-PV resin was characterised by infrared spectrometry and thermal gravimetric analysis. The optimum pH value for quantitative sorption is 8-9, and desorption can be achieved by using 5.0-10.0 ml of 2 M HCl. The effects of diverse ions on the sorption and recovery of aluminium have been studied. The capacity of sorbent was 6.45±0.59 mg g⁻¹ Al XAD-1180-PV. Recoveries for aluminium from water samples were in the range 95-105%. The accuracy of procedure was confirmed by aluminium determination in certified reference materials. The method developed was applied with varying results to the analysis of natural water, haemodialysis fluids and microwave digested red wine samples from Tokat City.     

Sample and Sorbent Integrity During Combustion Source Sampling

Abstract

A research program was initiated to evaluate the stability of selected organic compounds collected on porous polymer sorbents during combustion source sampling. This type of study is necessary to determine if destruction and removal of hazardous materials waste has occurred during incineration and not as a result of the sampling and analytical approach used. Two compounds, hexachlorobenzene and toluene diisocyanate, were selected for study. Due to difficulties encountered in preliminary work, studies on toluene diisocyanate were discontinued. Hexachlorobenzene sorbed onto XAD-2 resin at the 1 μg level was exposed to the following conditions intended to simulate hazardous waste incineration stack samplin: moist air, moist air in combination with HCl (two concentrations), and warm air. Recoveries following exposure were determined for each of three trials. The results indicate that hexachlorobenzene sorbed onto XAD-2 is stable with respect to the conditions routinely encountered during incineration stack sampling.     

Sorption of organic compounds from urine in mutagenicity testing: choice of sorbent

The choice of sorbents for urine mutagenicity testing was investigated. 14C-Labelled compounds were dissolved in urine and extracted from it by sorption with seven different sorbents singly or in combination. The compounds were desorbed with acetone. Sorption was examined under various experimental conditions. Except for two strong ionic compounds satisfactory extraction was achieved with a combination of three sorbents: Amberlite XAD-2, XAD-7, and Sep-Pak Silica. Filtration of the urine or contact of it with the walls of the experimental equipment could lead to substantial losses. Implications of these results for urine mutagenicity testing and possibilities for further optimization of the method are discussed.     

Storage stability of ketones on carbon adsorbents

Activated coconut carbon constitutes the more widely used sorbent for preconcentration of volatile organic compounds in sampling workplace air. Water vapour is always present in the air and its adsorption on the activated carbon surface is a serious drawback, mainly when sampling polar organic compounds, such as ketones. In this case, the recovery of the compounds diminishes; moreover, ketones can be decomposed during storage. Synthetic carbons contain less inorganic impurities and have a lower capacity for water adsorption than coconut charcoal. The aim of this work was to evaluate the storage stability of various ketones (acetone, 2-butanone, 4-methyl-2-pentanone and cyclohexanone) on different activated carbons and to study the effect of adsorbed water vapour under different storage conditions. The effect of storage temperature on extraction efficiencies was significant for each ketone in all the studied sorbents. Recovery was higher when samples were stored at 4 degrees C. The results obtained for storage stability of the studied ketones showed that the performance of synthetic carbons was better than for the coconut charcoals. The water adsorption and the ash content of the carbons can be a measure of the reactive sites that may chemisorb ketones or catalize their decomposition. Anasorb 747 showed good ketone stability at least for 7 days, except for cyclohexanone. After 30-days storage, the stability of the studied ketones was excellent on Carboxen 564. This sorbent had a nearly negligible ash content and the adsorbed water was much lower than for the other sorbents tested.     

Determination of hexahydrophthalic anhydride in air using gas chromatography.

Two methods for the determination of hexahydrophthalic anhydride (HHPA) in air were developed. In a solid sorbent method, HHPA was sampled in Amberlite XAD-2 tubes, eluted in toluene and analysed by gas chromatography with flame ionization detection. The sampling rates were 0.2 and 1.0 l/min. At 15 micrograms/m3 (relative humidity less than 2%) and 27 micrograms/m3 (relative humidity 70%) no breakthrough was observed. However, at 160 micrograms/m3 (relative humidity less than 2%), 6% breakthrough was found. The sampling efficiency of the sampling rates 0.2 and 1.0 l/min did not differ. In a bubbler method, HHPA was sampled in bubblers filled with 0.1 M sodium hydroxide solution. The sodium salt of hexahydrophthalic acid was formed. No breakthrough was observed using a sampling rate of 1.0 l/min. The samples were stable during storage for eight weeks in a refrigerator. The HHP acid was esterified with methanol-boron trifluoride and analysed by gas chromatography-flame ionization detection. Apparatus for the generation of standard atmospheres of HHPA, in the range of 10-3000 micrograms/m3, was developed using the diffusion principle. For the solid sorbent method the precision (coefficient of variation) of the overall method was 2-7%, and for the bubbler method 3-19% (range 15-160 micrograms HHPA/m3; relative humidity = less than 2-70%). A comparison between the two methods was performed using the standard atmosphere. The concentrations found by the solid sorbent method were 86-98% of those found by the bubbler method (range 15-160 micrograms HHPA per m3; relative humidity = less than 2-70%). In work environment air, 93% was found using the solid sorbent method relative to the bubbler method at a mean concentration of 330 micrograms/m3 (coefficient of variation = 39%; range 200-540 micrograms/m3). For both methods, concentrations greater than 3 micrograms/m3 could be quantified at 60 min sampling with a sampling rate of 1.0 l/min.