Review of advances in the thin layer chromatography of pesticides: 2006–2008

Applications of thin layer chromatography and high performance thin layer chromatography for the separation, detection, qualitative and quantitative determination, and preparatire isolation of pesticides and their metabolites are reviewed for the period from July 1, 2006 to November 1, 2008. Analyses are described for a variety of sample types and pesticide classes. In addition to references on residue and formulation analysis, studies such as pesticide-structure relationships, identification and characterization of plant pesticides, metabolism, degradation, mobility, and lipophilicity are covered. Future prospects for pesticide thin layer chromatography are also considered.     

Review of advances in the thin layer chromatography of pesticides: 2008–2010

Techniques and applications of thin layer chromatography (planar chromatography) for the separation, detection, qualitative and quantitative determination, and preparative isolation of pesticides and their metabolites and other related compounds are reviewed for the period from November 1, 2008 to November 1, 2010. Analyses are described for a variety of samples types and pesticide classes. In addition to references on residue analysis, studies such as pesticide structure-retention relationships, identification and characterization of plant pesticides and synthesized pesticides, metabolism, degradation, mobility, identification of biomarkers for detection of herbicide effects in plants, and lipophilicity are covered.     

Review of advances in the thin layer chromatography of pesticides: 2010–2012

Techniques and applications of thin layer chromatography (planar chromatography) for the separation, detection, qualitative and quantitative determination, and preparative isolation of pesticides and their metabolites and some related pollutants are reviewed for the period from November 1, 2010 to November 1, 2012. Analyses are described for a variety of samples types and pesticide classes. In addition to references on residue analysis, studies such as pesticide structure – retention relationships, identification and characterization of natural and synthesized pesticides, metabolism, degradation, mobility, lipophilicity, and mechanism of action are covered.     

Review of advances in the thin layer chromatography of pesticides: 2012–2014

Publications reporting techniques and applications of thin layer chromatography (planar chromatography) for the separation, detection, qualitative, and quantitative determination, and preparative isolation of pesticides and their metabolites are reviewed for the period from November 1, 2012 to November 1, 2014. Analyses are described for a variety of sample types and pesticide classes. In addition to references on residue analysis, studies such as pesticide structure – retention relationships, identification and characterization of natural and synthesized pesticides, metabolism, bioactivity, degradation, soil mobility, and lipophilicity are covered.     

Evaluation of the mobility of c14‐labelled pesticides in soils by thin layer chromatography using a linear analyser

Abstract

The mobility of seven pesticides in a chromic cambisol soil was studied by soil thin layer chromatography. Pesticide mobilities were determined by means of conventional autoradiographs of the chromatograms, as well as from sequential series of curves and images of the pesticide spots provided by a linear analyser. The R _f values obtained from the autoradiographs and those provided by the linear analyser were quite consistent. Based on such values, pesticide mobility decreased in the following order: acephate > fluometuron > atrazine > ethofumesate > metolachlor > diazinon > glyphosate. According to the mobility scale proposed by Helling and Turner (1968), acephate is highly mobile; atrazine, fluometuron, ethofumesate and metolachlor are moderately mobile; diazinon is slightly mobile; and glyphosate is immobile. The images provided by the linear analyser allow to determine the R _f values for the zones of maximum activity in the pesticide spots (R _f ^max), as well as the activities of different spot zones and those corresponding to R _f and R _f ^max. The results obtained show the image analyser to provide more expeditious R _f measurements from the chromatograms and open up new prospects for using soil TLC to investigate pesticide mobility.     

Atmospheric nitrogen fluxes at the Belgian coast: 2004–2006

Daily and seasonal variations in dry and wet atmospheric nitrogen fluxes have been studied during four campaigns between 2004 and 2006 at a coastal site of the Southern North Sea at De Haan (Belgium) located at coordinates of 51.1723° N and 3.0369° E. Concentrations of inorganic N-compounds were determined in the gaseous phase, size-segregated aerosol (coarse, medium, and fine), and rainwater samples. Dissolved organic nitrogen (DON) was quantified in rainwater. The daily variations in N-fluxes of compounds were evaluated with air-mass backward trajectories, classified into the main air-masses arriving at the sampling site (i.e., continental, North Sea, and Atlantic/UK/Channel).The three, non-episodic campaigns showed broadly consistent fluxes, but during the late summer campaign exceptionally high episodic N-deposition was observed. The average dry and wet fluxes for non-episodic campaigns amounted to 2.6 and 4.0 mg N m^?2 d^?1, respectively, whereas during the episodic late summer period these fluxes were as high as 5.2 and 6.2 mg N m^?2 d^?1, respectively.Non-episodic seasons/campaigns experienced average aerosol fluxes of 0.9–1.4 mg N m^?2 d^?1. Generally, the contribution of aerosol NH₄⁺ was more significant in the medium and fine particulate fractions than that of aerosol NO₃^?, whereas the latter contributed more in the coarse fraction, especially in continental air-masses. During the dry mid-summer campaign, the DON contributed considerably (～15%) to the total N-budget.Exceptionally high episodic aerosol-N inputs have been observed for the late summer campaign, with especially high deposition rates of 3.6 and 2.9 mg N m^?2 d^?1 for Atlantic/UK/Channel and North Sea-continental (mixed) air-masses, respectively. During this pollution episode, the flux of NH₄⁺ was dominating in each aerosol fraction/air-mass, except for coarse continental aerosols. High deposition of gaseous-N was also observed in this campaign with an average total N-flux of 2–2.5-times higher than in other campaigns.     

Simultaneous determination of acidic pesticides in vegetables and fruits by liquid chromatography—tandem mass spectrometry

A sensitive and efficient method has been developed for the simultaneous determination of 73 multi-class acidic pesticides, such as phenoxy acid and sulfonylurea herbicides, in vegetables and fruits. The sample preparation procedure was carefully optimized for the efficient removal of co-extracted matrix components. The method involves extraction of acidic pesticides with acetonitrile containing hydrochloric acid, removal of water from crude extract by salting out, and sequential cleanup by octadecylsilyl silica gel and silica gel columns. For samples containing high amounts of pigments, such as spinach, additional cleanup using a graphitized carbon column was performed prior to liquid chromatography–mass spectrometry (LC–MS/MS) analysis. Recovery tests were performed for five times for each sample of cabbage, spinach, potato, eggplant, orange, and apple fortified at 0.01 mg kg?1. Out of the 73 tested pesticides, 70 for cabbage, 67 for spinach, 69 for potato, 67 for eggplant, 64 for orange, and 70 for apple were within the range of 70–120%, with relative standard deviations below 25%. Nitenpyram and pyrasulfotole showed low recoveries for all the samples tested, probably due to low recoveries from silica gel column. The developed method effectively removed co-extracted matrix components and was highly selective, with no interfering peaks found in the chromatograms of blank samples. The overall results indicate that the developed method is suitable for the quantitative analysis of acidic pesticide residues in vegetables and fruits.     

Adverse birth outcomes in the vicinity of industrial installations in Spain 2004–2008

Industrial activity is one of the main sources of ambient pollution in developed countries. However, research analyzing its effect on birth outcomes is inconclusive. We analyzed the association between proximity of mother’s municipality of residence to industries from 24 different activity groups and risk of very (VPTB) and moderate (MPTB) preterm birth, very (VLBW) and moderate (MLBW) low birth weight, and small for gestational age (SGA) in Spain, 2004–2008. An ecological study was defined, and a “near vs. far” analysis (3.5 km threshold) was carried out using Hierarchical Bayesian models implemented via Integrated Nested Laplace Approximation. VPTB risk was higher for mothers living near pharmaceutical companies. Proximity to galvanization and hazardous waste management industries increased the risk of MPTB. Risk of VLBW was higher for mothers residing near pharmaceutical and non-hazardous or animal waste management industries. For MLBW many associations were found, being notable the proximity to mining, biocides and animal waste management plants. The strongest association for SGA was found with proximity to management animal waste plants. These results highlight the importance of further research on the relationship between proximity to industrial sites and the occurrence of adverse birth outcomes especially for the case of pharmaceutical and animal waste management activities.     

Biogeochemical Control of the Coupled CO2–O2 System of the Baltic Sea: A Review of the Results of Baltic-C

Past, present, and possible future changes in the Baltic Sea acid–base and oxygen balances were studied using different numerical experiments and a catchment–sea model system in several scenarios including business as usual, medium scenario, and the Baltic Sea Action Plan. New CO₂ partial pressure data provided guidance for improving the marine biogeochemical model. Continuous CO₂ and nutrient measurements with high temporal resolution helped disentangle the biogeochemical processes. These data and modeling indicate that traditional understandings of the nutrient availability–organic matter production relationship do not necessarily apply to the Baltic Sea. Modeling indicates that increased nutrient loads will not inhibit future Baltic Sea acidification; instead, increased mineralization and biological production will amplify the seasonal surface pH cycle. The direction and magnitude of future pH changes are mainly controlled by atmospheric CO₂ concentration. Apart from decreasing pH, we project a decreasing calcium carbonate saturation state and increasing hypoxic area.     

Rapid multiresidue determination for currently used pesticides in agricultural drainage waters and soils using gas chromatography–mass spectrometry

An efficient and sensitive method for simultaneous determination of 38 pesticides in agricultural drainage waters and soils has been developed and validated. Water samples were extracted using solid-phase extraction with C18 cartridges while solid samples (suspended particle matter and soil) were extracted by using the quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction method. The target pesticides were analyzed by using gas chromatography-mass spectrometry with electron impact ionization. The proposed method allowed a simultaneous determination and confirmation of a large number of pesticides in agricultural drainage waters, suspended particle matters and soils/sediments with a good reproducibility and low detection limits. The developed method was applied to a survey of pesticides in a vegetable growing area of Guangzhou, China. The pesticides commonly found in the area were butachlor, carbofuran, dichlorvos, fipronil, isocarbophos and pyridaben.     

Seasonal variations of particle-associated nitrosamines by gas chromatography–mass spectrometry in the atmospheric environment of Zonguldak, Turkey

A gas chromatography–mass spectrometry method has been proposed for the determination of low-level mutagenic and carcinogenic nitrosamines in particulate matter. The method includes the collection of particulate matters (PM_2.5 and PM₁₀) using a dichotomous Partisol 2025 sampler and extraction of the compounds from aqueous solution with dichloromethane/2-propanol after sonication with a slightly basic water solution prior to their GC-MS analysis in electron impact mode. The obtained recoveries of nitrosamines ranged from 92.4 to 99.2 %, and the precision of this method, as indicated by the relative standard deviations, was within the range of 0.95–2.46?%. The detection limits obtained from calculations using the GC-MS results based on S/N?=?3 were found within the range from 4 to 22 pg/m³. The predominant nitrosamines determined in particulate matter were N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodibutylamine and N-nitrosomorpholine. Furthermore, N-mono- and dinitrosopiperazine and N-nitrosoethylbutylamine were also determined. N-dinitrosopiperazine was detected in PM_2.5 samples at the highest concentrations of up to 22.85 ng/m³ and in PM_2.5–10 samples at concentrations up to 7.60 ng/m³ in winter, whereas it was found in PM_2.5 samples up to 5.15 ng/m³ and in PM_2.5–10 samples up to 3.12 ng/m³ in summer. The total concentrations of nitrosamines were up to 161.4 ng/m³ in fine and 53.90 ng/m³ in coarse fractions in winter, whereas in summer were up to 35.24 and 12.60 ng/m³, respectively. The concentration levels of nitrosamines fluctuated significantly within a year, with higher means and peak concentrations in the winter compared to that in the summertime. The seasonal variations of particle-associated nitrosamine concentrations were investigated together with their relationships with meteorological parameters using Pearson’s correlation analysis in the winter and summer periods. Analysis of variance was used to determine which concentrations of nitrosamines were statistically different from one another and, together with meteorological parameters and discriminant analysis, was used to classify the particle samples by particle size according to seasons. The classification results of the particle samples in different seasons were very satisfactory, allowing 99.5 % of cases to be correctly grouped.     

The spatial–temporal chemical footprint of pesticides in China from 1999 to 2018

Environmental Science and Pollution Research - The massive use of pesticides brings considerable environmental and human health impacts. This study conducted an overall assessment of the ecological...     

Assessment of GC–MS response of selected pesticides in apple matrices related to matrix concentration

A uniform analyte response is required for GC–MS analysis in order to obtain acceptable quantitative results. The response of pesticides in complex matrices is susceptible to variation due to the interactions of co-extractives, both with pesticides or with GC–MS system. This study was conducted to determine the magnitude of the interactions, called matrix effect, and their behavior with the matrix dilution. The response of pyrimethanil (4,6-dimethyl-N-phenylpyrimidin-2-amine), cyprodinil (4-cyclopropyl-6-methyl-N-phenylpyrimidin-2-amine), trifloxystrobin (methyl-(2Z)-2-methoxyimino-2-[2-[[(E)-1-[3(trifluoromethyl)phenyl]ethylidene amino]oxymethyl]phenyl]acetate) and bifenthrin(2-methyl-3-phenylphenyl)methyl-3-[(Z)-2-chloro-3,3,3-trifluoroprop-1-enyl]-2,2-dimethylcyclopropane-1-carboxylate), used in apple crops protection, was evaluated in different concentrations of peel and flesh extracts of Granny Smith, Golden Delicious and Demi Rouge, selected as representatives of different matrix types. The matrix effect ranged from ?0.05 to 146.14%, depending on matrix type and pesticide. The highest response variation was observed in extracts of Granny Smith—an enhancement in flesh and suppression in peel extract. With the dilution, the matrix effect decreased with different magnitudes, but for Granny Smith peel extract an inverted effect was observed. The presence of the matrix effect in GC–MS pesticides analysis was obvious, requiring the application of matrix-matched calibration in quantification procedures for each variety, with calibration standards matched by the matrix concentration.     

The key role of hydrophobicity in the determination of pharmaceuticals by liquid chromatography–electrospray ionization-mass spectrometry under the interference of natural organic matter

Environmental Science and Pollution Research - The determination of trace-level pharmaceuticals in water is generally performed using liquid chromatography combined with mass spectrometry, which is...     

Measurements of the natural β-activity and the atmospheric polar conductivity in the atmospheric surface layer

Like the natural radioactivity, the polar conductivity of the air shows a pronounced diurnal variation: the records show a sharp peak in the early morning and a very flat minimum in the afternoon. The diurnal variation is most pronounced from late spring to early autumn, i.e. it is least during late autumn, in the winter and in early spring when the diurnal variation of the turbulent transfer is small. Consequently, the relationship between natural radioactivity and polar conductivities is slight during this period.From correlation studies we observe a relationship between the natural β-activity and the polar conductivities in situations with stable stratification. This probably depends on the influence of stability in the low layer upon the variations of the natural atmospheric radioactivity.When applying Fourier analysis to the variations of the polar conductivities greater amplitudes appear for the negative polar conductivity than for the positive polar conductivity. This feature is found for all wave lengths and throughout the year. We have no explanation for these differences.     

The sea–air exchange of mercury (Hg) in the marine boundary layer of the Augusta basin (southern Italy): Concentrations and evasion flux

The first attempt to systematically investigate the atmospheric mercury (Hg) in the MBL of the Augusta basin (SE Sicily, Italy) has been undertaken. In the past the basin was the receptor for Hg from an intense industrial activity which contaminated the bottom sediments of the Bay, making this area a potential source of pollution for the surrounding Mediterranean. Three oceanographic cruises have been thus performed in the basin during the winter and summer 2011/2012, where we estimated averaged Hg_atm concentrations of about 1.5 ± 0.4 (range 0.9–3.1) and 2.1 ± 0.98 (range 1.1–3.1) ng m⁻³ for the two seasons, respectively. These data are somewhat higher than the background Hg_atm value measured over the land (range 1.1 ± 0.3 ng m⁻³) at downtown Augusta, while are similar to those detected in other polluted regions elsewhere. Hg evasion fluxes estimated at the sea/air interface over the Bay range from 3.6 ± 0.3 (unpolluted site) to 72 ± 0.1 (polluted site of the basin) ng m⁻² h⁻¹. By extending these measurements to the entire area of the Augusta basin (∼23.5 km²), we calculated a total sea–air Hg evasion flux of about 9.7 ± 0.1 g d⁻¹ (∼0.004 t yr⁻¹), accounting for ∼0.0002% of the global Hg oceanic evasion (2000 t yr⁻¹). The new proposed data set offers a unique and original study on the potential outflow of Hg from the sea–air interface at the basin, and it represents an important step for a better comprehension of the processes occurring in the marine biogeochemical cycle of this element.     

Determination of neonicotinoids in Estonian honey by liquid chromatography–electrospray mass spectrometry

The aim of the study was to provide a comprehensive overview of neonicotinoid pesticide residues in honey samples for a single country and compare the results with the import data for neonicotinoid pesticides. The levels of four neonicotinoid pesticides, namely thiamethoxam, imidacloprid, acetamiprid, and thiacloprid, were determined in 294 honey samples harvested from 2005 to 2013 from more than 200 locations in Estonia. For the analyzed honey samples, 27% contained thiacloprid, and its levels in all cases were below the maximum residue level set by the European Union. The other neonicotinoids were not detected. The proportion of thiacloprid-positive samples for different years correlates well with the data on thiacloprid imports into Estonia, indicating that honey contamination with neonicotinoids can be estimated based on the import data.