Gas Chromatography Coupled With Electron Capture Detector Research Articles

Distribution, Source Apportionment and Health Risk Assessment of Organochlorine Pesticides in Drinking Groundwater

Groundwater samples of Ile-Ife, Osun State, Nigeria were investigated for their organochlorine pesticides (OCPs) levels. Probable sources of the OCPs and health risks associated with their consumption along with the water were determined in order to establish the potability of the groundwater samples. Quantitative determination of the OCPs was carried out by Gas Chromatography coupled with Electron Capture Detector (GC-ECD) after liquid–liquid extraction with dichloromethane (DCM). Results indicated that all the analyzed OCPs except p,p´-dichlorodiphenylethane were detected with high concentrations in the groundwater. Hepachlor (14.60 ± 3.60 µg/L) and methoxychlor (12.60 ± 2.20 µg/L) showed dominant concentrations that were higher than 0.02 ng/L maximum residue levels (MRLs) recommended by the European Union. Levels of the OCPs in the samples followed the decreasing trend: cyclodienes > diclorophehylethanes > chlorinated cyclohexanes, while the predominant source of the analyzed pesticides could be ascribed to aerial transportation from fresh applications in homes within the community. The carcinogenic health risk assessment also revealed consistent higher values of HQ and CR in children as opposed to adults, indicating that children are the more vulnerable population to the analyzed environmental contaminants.

Determination of multi-class pesticides residues of cow and human milk samples from Iran using UHPLC-MS/MS and GC-ECD: A probabilistic health risk assessment

Raw, pasteurized, powdered cow milk and human milk samples from Tehran, Iran were investigated for the residual of fifty pesticides with the aid of gas chromatography coupled with electron capture detector (GC-ECD) and mass detector for confirmation; and ultra-high performance liquid chromatography-tandem mass spectroscopy (UHPLC-MS/MS). No pesticide residue was determined in more than 91% of examined samples. However, the dimethoate residue was detected in 3 raw milk samples in levels higher than EU recommended MRL. While in 3 human milk samples, organochlorine pesticides residue, p,p′-DDT, and p,p′-DDD was recognized below MRLs, only in 1 human sample residue of p,p′-DDE was more than CODEX recommended MRL. HI in adults and children were 0.72 and 3.55, respectively. However, the health risk assessment based on HI demonstrated that adult consumers are not at considerable risk. The HI, higher than 1 in children, confirms the risks raised due to ingestion of organochlorine (OCP) and organophosphorus (OPP) pesticides via milk consumption. In addition, no carcinogenic risk to milk consumers was calculated. Therefore, implementation of good farming practices on farms, improving the knowledge and consciousness of pesticide users, use other safe methods for pest control such as biotechnology-based, and use a rational program for application of pesticides, continuous monitoring of pesticides in crops, and strict government regulations on pesticide residues in food are recommended.

Study of Organochlorine Pesticide Residues Analysis in Water, Fish and Sediment using GC-ECD in River Loko, Nasarawa State, Nigeria

Levels of organochlorine pesticide (OCPs) residues in sediment, water and fish in River Loko, Nasarawa State, Nigeria, were evaluated for possible pollution of the aquatic system. Water and sediment samples were collected from the river at 3 locations. Fish caught in the river were bought from fishermen at the bank of the river. The samples were collected in rainy season and preserved according to standard methods. Liquid-liquid extractions of samples were carried out, and then quantified using Gas Chromatography Coupled with Electron Capture Detector (GC-ECD). The OCPs levels ranged from 0.06 to 1.53 μɡ/Kɡ in sediment, 0.03 to 1.34 μɡ/Kɡ in water and 0.02 to 1.34 μɡ/Kɡ in fish. 2, 4-Dichlorophenoxacetic acid (2, 4-D) was the most accumulated OCP in sediment (1.64±0.10 μɡ/Kɡ), water (1.34±0.08 μɡ/Kɡ), and fish (1.34 μɡ/Kɡ). Concentrations of OCPs generally varied in the order of sediment > water > water ~ fish. ANOVA shows that concentrations of OCPs in water and fish were significantly (p ≤ 0.05) lower compared to sediment, except for mecoprop, imidacloprid, 2, 4-D, and aldrin, which were not significantly different in the samples. Pearson correlation matrix for OCPs in water and sediment show moderate to very strong and positive correlations except for mecoprop (-0.705), alachlor (-0.217), imidacloprid (-0.082), permethrin (-0.339) and aldrin (-0.795). Concentrations of OCPs were within the FAO/WHO acceptable limits except for aldrin, mecoprop, metolachlor, simazine, DDT and dieldrin. Regular monitoring of the quality of River Loko becomes necessary due to accumulation of OCPs.

Polychlorinated Biphenyls in Groundwater of Grombalia: Optimization and Validation of Analytical Procedures Using Gas Chromatography with Electron Capture Detector

Now-a-days, the management of water resources is one of the main global challenges, both at the level of agricultural and industrial activities as well as direct consumption and poses various problems of both qualitative and quantitative order. In the entire world, groundwater suffers from various sources of contamination principally due to overusing of chemical fertilizer in the agricultural sector. The contamination of groundwater by organochlorines and more precisely by polychlorinated biphenyls (PCBs) is a problem of global order. As we know that Tunisia is based on agriculture work like citrus, olive, wheat and cereal, the study of water pollution is a topical subject that remains unclear. Polychlorinated Biphenyls (PCBs) are one class of persistent organic pollutants. PCBs in recent decades have attracted the attention of scientific and policy maker communities due to their persistence, their high capacity to bioaccumulation in the food chain and their toxic properties. This work is aimed to develop an efficient method for the analysis of targeted PCBs in groundwater sample taken from the region of Grombalia. Optimization of PCBs extraction was performed with applied the experimental design of Dohlert with two factors, solvent and number of extractions. Analysis of PCBs was performed with gas chromatography coupled with electron capture detector (GC-ECD) with an optimization of temperature program. Results shows that the optimal temperature program was obtained with a starting temperature of 160°C up to 280°C during 10 min with a rate of 4°C min-1 and the optimal condition of extraction was obtained with a mixture of hexane/ether (75/25%) and a three time extractions. The optimized method has been applied to the analysis of the PCBs in nine groundwater samples collected from the Grombalia city. Results indicate that PCBs concentrations varied between 5.2 μgL-1 and 169 μgL-1. However, the maximum acceptable concentration (MAC) in drinking and surface water recommended by EPA is 0.5 μgL-1 with a detection limit (LD) ranged between 0.05 to 1.9 μg L-1.

Comparative study of different sorbents for clean-up for pyrethroid analysis in cocoa powder by GC-ECD: A preliminary study

Three types of solvents and 13 combinations of sorbents were tested to extract pyrethroids (lambda-cyhalothrin, permethrin, cypermethrin, fenvalerate, and deltamethrin) from cocoa powder and to remove interferences during clean-up step before being quantified by gas chromatography coupled with electron capture detector (GC-ECD). The result was analysed based on recovery study by spiking the cocoa powder with known amount of targeted pyrethroids. Acetonitrile, methanol, and n-hexane were compared as the solvents and the result showed that acetonitrile is relatively better in extracting pyrethroids. Moreover, 13 treatments, singly or combination of primary secondary amine (PSA), graphitized carbon black (GCB), C18, and florosil, were tested for clean-up step. The clean-up study shows that only combination of PSA and GCB; combination of C18 and Florisil; and combination of GCB and florisil comply the recovery guideline suggested by AOAC and EU, thus are suggested for clean-up for pyrethroid analysis in cocoa powder.

Disinfection By-products and the Relevant Health Risk in the Water Supply System in H City of Zhejiang Province

The occurrence of 18 types of disinfection by-products (DBPs) in two waterworks and the corresponding water supply networks of H City in Zhejiang Province was determined by gas chromatography coupled with electron capture detector (GC-ECD). The correlation between DBPs and organic precursors, and health risks caused by DBPs, were discussed. Results showed that the disinfection by-products detected in drinking water in H City mainly include trihalomethanes (THMs), haloacetic acid (HAAs), haloacetonitrile (HANs) and trichloronitromethane (HNMs), with highest concentrations of THMs followed by HAAs. In the finish water of CX Waterworks and tap water supplied by CX Water works, concentrations of THMs ranged from 7.70 to 32.73μg·L-1and 9.00 to 51.42μg·L-1, respectively, and those of HAAs 3.05 to 21.30μg·L-1 and 6.00 to 26.79μg·L-1, respectively. The THMs in finished water and tap water of TH Waterworks were in the range 8.65-38.76μg·L-1 and 12.09-42.04μg·L-1, respectively, and those of HAAs were 2.42-14.79μg·L-1 and 2.80-33.40μg·L-1, respectively. The DBPs in the finished and tap water of the two waterworks were at lower levels than the limitations regulated by the Sanitary Standard for Drinking Water (GB 5749-2006). The index of dissolved organic carbon (DOC) and UV254 were adopted to describe the organic compounds, and it was found that trichloromethane (TCM) was significantly negatively correlated with DOC and UV254in tap water. Based on the EPA recommended health risk assessment model, the carcinogenic and non-carcinogenic risks of chlorine disinfection by-products in the oral intake route were calculated. It was found that the carcinogenic risks caused by the disinfection by-products in the finished water and tap water of H City were 5.94×10-6-4.76×10-5 and 5.94×10-6-5.56×10-5, respectively, while the non-carcinogenic risks were 0.91×10-2-4.20×10-2 and 1.26×10-2-4.72×10-2, respectively. The carcinogenic risk is mainly from THMs:bromodichloromethane (BDCM) contributes the highest cancer risk, and the non-carcinogenic risk is mainly from TCM.

Assessment of the retardation of selected herbicides onto Danube sediment based on small column tests

This study utilizes column tests to investigate the retardation of certain herbicides with different hydrophobicities (atrazine, alachlor and trifluralin) during transport through surface Danube sediment. The influence of water matrix on the retardation factor Rd and Freundlich constant Kf is investigated. The results are compared with batch tests to establish whether different methodologies result in similar or different conclusions. A stainless steel column was filled with natural Danube sediment. Three water matrices were investigated: synthetic, Danube surface, and deep groundwater rich in natural organic matter (NOM). The goal was to examine whether different water matrices would result in changes in the Rd and corresponding Kf values. After a tracer experiment, single herbicide solutions were tested in the three water matrices. Herbicides were analyzed by gas chromatography coupled with electron capture detector (GC/ECD). Retardation factors obtained in the column experiments were calculated using Transmod software (version 2.2). The Kf values calculated were compared with the values obtained in previous batch experiments. A breakthrough curve (BTC) for trifluralin could not be obtained during the experiment. Atrazine Rd values were almost the same in the natural matrices (54 and 55 for the ground and surface waters, respectively), and lower in the synthetic water (40). Alachlor Rd values in the three water matrices were very similar (30–35). The corresponding Kf values for alachlor (8.47–17.4) were lower than those of atrazine (13.5–27.9). These results differ from those obtained by earlier batch tests, which showed similar Kf values for both atrazine (4.4–9.2) and alachlor (4.43–10.35) in all three matrices. In contrast to the results observed during the batch tests, the column tests exhibited higher Kf values in the natural water matrices than the synthetic water, possibly due to the influence of dissolved organic carbon on herbicide sorption. Of the three herbicides investigated, the smallest retardation was observed for alachlor. This was unexpected given the relative hydrophobicities of alachlor and atrazine. The potential risk of transport through the sediment may therefore be greater for alachlor than the other two herbicides. This was indicated neither by the batch tests nor from the Koc–Kow estimations. Both herbicides exhibited similar Kd and Kf values in the batch tests, and lower values in the natural water matrices. In comparison, the column tests showed higher Kf values, with higher values in the natural matrices than in the synthetic water matrix.

Optimization and validation of the salting-out assisted liquid-liquid extraction method and analysis by gas chromatography to determine pesticides in water

The salting-out assisted liquid-liquid extraction (SALLE) was developed for the analysis of four pesticides (cypermethrin, chlorpyrifos, deltamethrin, and thiamethoxam) in water samples. For its optimization, a 2³ factorial design was used to evaluate the simultaneous behavior of three factors: sample and extraction solvent ratio, saline concentration, and stirring mode. A 1.0 mL saline solution (NaCl) was added to the single-phase mixture of water and extraction solvent to separate the phases. The mixture was stirred, allowed to stand and the top organic phase containing the pesticides of interest was analyzed by gas chromatography coupled with electron capture detector (GC/ECD). The optimized method was validated for some merit figures. The limit of detection of the method ranged from 0.15 to 5.5 µg L-1 and the limit of quantification from 5.5 to 18.2 µg L-1. The method showed satisfactory results for the linearity (R2 ≥ 0,990), precision (CV < 9 %) and accuracy (72 % ≤ recovery ≤ 90 %) for all the assessed analytes. The method showed to be simple, efficient and inexpensive for the extraction of pesticide residues. The validated method was applied to ten samples of water collected in the Zona da Mata region of the state of Minas Gerais, Brazil.

Residue determination of triclopyr and aminopyralid in pastures and soil by gas chromatography-electron capture detector: Dissipation pattern under open field conditions

In this study, a new method for the simultaneous quantitative determination of triclopyr and aminopyralid in forage grass, hay, and soil was developed and validated using gas chromatography coupled with electron capture detector (GC-ECD). In this method, a simple and maneuverable esterification reaction was applied to convert the two acidic herbicides into their ester form with methanol. The target compounds were extracted with 1% hydrochloric acid-acetonitrile, esterified, purified by florisil solid-phase extraction cartridge, and detected in a single run by the GC-ECD. The average recoveries using this method, at different fortified levels, ranged from 80% to 104% with intra-day and inter-day RSDs in the range of 1.2–10.8% and 3.3–10.3% for both the herbicides, respectively. The LODs were below 0.02 mg/kg while the LOQs were below 0.05 mg/kg, both of which were much lower than the maximum residue limits (MRLs) of 25–700 mg/kg in pastures, as established by the USA (the code of federal regulations). The open field dissipation and residual analysis in pastures and soil were conducted with the commercial formulation at two locations. With time, both triclopyr and aminopyralid dissipated via first-order kinetics. In forage grass, both compounds degraded rapidly over the first 14- or 21-d period and at a slow rate over the remainder of experimental days. In soil, they degraded at a relatively slow rate, and dissipated steadily to below or close to the LOQ by 60-d post application. The half-lives of triclopyr were 1.4–1.8 d and 6.2–9.0 d and aminopyralid were 1.7–2.1 d and 8.2–10.6 d in terms of forage grass and soil, respectively. The terminal residue results indicated that on 7 d after the treatment, the residues of aminopyralid and triclopyr in forage grass and hay were lower than the MRLs set by the USA. This work can provide guidance on the reasonable use of these herbicides and also provide an analytical method for the determination of triclopyr and aminopyralid in pasture and soil.

Determination of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in some personal care products in Nigeria.

The study was carried out to determine the presence and concentration of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in some personal care products in Nigeria. Commonly used consumer care products grouped into four classes, namely: plastics, cosmetics, disinfectants and washing products, were purchased from some supermarkets in Ile-Ife, Nigeria. The solid samples were pulverized and the PAHs and OCPs were extracted with n-hexane and dichloromethane, respectively using Soxhlet extraction method, while the liquid samples were extracted using liquid-liquid extraction method. The quantitative and qualitative determinations were carried out using Gas Chromatography coupled with Flame Ionization Detector (GC-FID) for PAHs, and Gas Chromatography coupled with Electron Capture Detector (GC-ECD) for the OCPs. The results for PAHs analysis gave an overall mean concentration of 3259.10 ± 5223.16 μg g-1 for plastics and 8388.00 ± 7106.55 μg g-1 for cosmetics. Comparatively, the concentrations of PAHs in the cosmetic samples were higher than in plastics samples, while both values were greater than the recommended limits of PAHs in consumer care products as stipulated by the World Health Organization. For the OCPs, disinfectant samples had a total mean concentration of 10.65 ± 6.50 μg mL-1, while washing products had a total mean concentration of 35.31 ± 39.31 μg mL-1. The concentrations of OCPs in washing products were higher than their concentrations in disinfectant samples. The results of the OCPs in some samples were greater than Maximum Residual Limit (MRL) recommended by the European Commission. The study concluded that consumer care products used in this study contained PAHs and OCPs at levels that could be risky to human health if the consumer care products are not used with caution.

Multi-Residue Levels of Persistent Organochlorine Pesticides in Edible Vegetables: A Human Health Risk Assessment

Background: This study evaluates the quantitative assessment of persistent organochorine pesticide (OCPs) residues in vegetables (Senecio biafrae) from four selected cocoa plantations in Ekiti State, Nigeria. Methods: The pesticides were extracted from the vegetable samples by using USEPA 3500C method and later clean-up on activated silica gel. The pesticides residues in the samples were determined using Gas Chromatography coupled with Electron Capture Detector (GC-ECD). Results: The results showed that the analyzed samples were contaminated with ten OCPs. The mean OCPs concentration ranged from ND—0.399 mg/kg to ND—0.379 mg/kg during the wet and dry seasons respectively. α-BHC, β-BHC, p, p’-DDE, dieldrin, endrin, endosulfan sulphate and methoxychlor were not detected in the samples. Pesticides such as aldrin, endosulfan II, endrin aldehyde and heptachlor slightly exceeded their maximum residue limit. Conclusion: The hazard indices (HI) of heptachlor, endosulfan I, endosulfan II, aldrin, heptachlor-epoxide and p, p’-DDT exceeded 1 and thus pose likely potential non-carcinogenic health risk.

Organic Pesticides Concentration in Water, Sediments and Fish Tissues obtained from Ogbakiri River in the Niger-Delta Region, Nigeria and Its Health Implication on Human Consumption

Organic pesticides concentrations in tissues of Chrysichthys nigrodigitatus (catfish) and Liza falcipinis (mullet) sampled from Ogbakiri River, Niger Delta, Nigeria were investigated to find out the extent of pesticide contamination in the river and its possible health implication on human consumption assessed. Pesticides were analyzed using gas chromatography coupled with electron capture detector (GC-ECD). The concentration of pesticides ranged from 0.0010±0.0001 to 0.0095±0.0002 µg/l and 0.0007±0.0001 to 0.0110±0.0002µg/g in water and sediments, respectively. Similarly, pesticides concentration in fish tissues ranged from 0.0002±0.0001 to 0.0185±0.0002µg/g and 0.0003±0.0001 to 0.0098±0.0002µg/g in liver and muscle respectively. Moreso, to assess health risk concerns, the measure concentrations of pesticide residues were compared with regulatory benchmarks. Risk hazard estimates of dichlorodiphenyltrichloroethanes, Chlordanes, hexachlorobenzene in the studied fishes showed no potential adverse effect to human consumption at the observed concentrations. The cancer risk was also evaluated according to the guideline as stipulated by USEPA and was within acceptable risk range of 10-4. Thus exposed populations are not at cancer risk through consumption of fish from this river.

Characterisation of Polychlorinated Biphenyls in Coastal Inland Seawater, Nigeria

The concentrations of polychlorinated biphenyls (PCBs) were determined in samples of surface seawater collected from five (5) different locations along the coastline of a tropical lagoon. The surface water samples were analysed using gas chromatography coupled with electron capture detector (GC-ECD) with fifteen (15) PCB congeners detected across the studied area. The chlorobiphenyls levels are in the order Ebute Ero > Oko Baba > Ijora > Lagos Island > Unilag lagoon front with levels 107.89, 53.15, 34.90, 27.78, and 2.15 mg/L, respectively. The enhanced average concentration of PCBs at the Ebute Ero site is due to the predominance of PCB-180 and PCB-185. A negative correlation was found between the total PCB concentration and the level of dissolved oxygen. Although, the results indicated fairly high levels of PCBs, the anthropogenic contributions from industrial releases and domestic activities may be largely associated with the detected concentrations of the di-, tetra-, penta-, hexa-, hepta-, and octa-chlorobiphenyls.

Determination of pesticide residues in leafy vegetables at parts per billion levels by a chemometric study using GC-ECD in Cameron Highlands, Malaysia.

A simple and sensitive analytical method has been developed employing gas chromatography coupled with electron capture detector (GC-ECD), and validated for screening and quantification of 15 pesticide residues at trace levels in cabbage, broccoli, cauliflower, lettuce, celery, spinach, and mustard. The method consists of two steps, first, to determine the significance of each factor by Pareto chart followed by optimization of these significant factors using central composite design (CCD). Minitab statistical software was used for these multivariate experiments for the generation of 24-1 design and CCD matrices. The method evaluation was done by external standard calibration with linearity range between 0.5 and 3mg/kg, with correlation coefficient 0.99, limit of detection (LOD) ranges between 0.02 and 4.5ng/g, and limit of quantification (LOQ) ranges between 0.2 and 45ng/g. The average recovery was between 60% and 128%, with RSD 0.2-19.8%. The method was applied on real vegetable samples from Cameron Highlands.

A Purification Method for 10 Polybrominated Diphenyl Ethers in Soil Using Accelerated Solvent Extraction-Solid Phase Extraction

Abstract An optimized method was established for the determination of 10 polybrominated diphenyl ethers (PBDEs) in soil using gas chromatography coupled with electron capture detector (GC-ECD). Accelerated solvent extraction (ASE) was used to extract 10 PBDEs from soil and a comparative study on 4 kinds of extraction systems ( i -hexane, i -hexane-acetone (4:1, V/V ) n -hexane-acetone (1:1, V/V ), n -hexane-dichloromethane (1:1, V/V )) was conducted to obtain an optimal extraction effect of PBDEs. The purification of 10 PBDEs in soil solution was completed by solid phase extraction (SPE). Ten kinds of SPE columns with different filters were applied to the purification process. The optimized conditions were acquired using the extraction system of n -hexane-acetone (4:1, V/V ) and purification with acid silica gel column. Under the optimized conditions, the average recoveries of 10 PBDEs in soil ranged from 85.4% to 103.1% with the RSDs of 1.7%–4.6%. Method detection limits (MDLs) were 0.04–0.22 ng mL −1 . The method was simple, rapid and efficient, and quite feasible for the determination of the 10 PBDEs in contaminated soil.

Fluazinam Residue and Dissipation in Potato Tubers and Vines, and in Field Soil

Residual fluazinam in the environment may cause dermatitis and occupational asthma. Therefore, it is important to determine the dissipation behavior of fluazinam in edible raw food and in the environment. The aim of this study was to monitor a fungicide fluazinam on potato. A method for the analysis of fluazinam residue and its dissipation in potato plants and soil under field conditions was studied. Fluazinam residues were analyzed using a modified Quick, Easy, Cheap,Effective, Rugged, and Safe (QuEChERS) method and gas chromatography coupled with electron capture detector (GC-ECD). Mean recoveries and relative standard deviations (RSD) in potato plants, potatoes, and soil at three spiking levels were 85.1–99.5 and 0.7–2.8 %, respectively. The limits of quantification (LOQ) were 0.01 mg kg−1 for all three matrices. The dissipation dynamics of fluazinam were investigated in field trials in Hebei and Anhui provinces. In potato plants, fluazinam had a half-life of 2.5 days in Hebei and 3.6 days in Anhui. The half-life of fluazinam in soil was 4.7 days in Hebei and 13 days in Anhui. Terminal residues in soil samples ranged from 0.0925 to 0.949 mg · kg−1 and fluazinam was not detected in potato at pre-harvest intervals of five, seven, and 10 days. It was safe for fluazinam application on potato according to the recommended dosage and times.

Dichloro-diphenyl-trichloro-ethane (DDT) and hexachlorohexane (HCH) pesticide residues in foodstuffs from markets in Ile-Ife, Nigeria

Levels of dichlorodiphenyltrichloroethanes (DDTs) and Hexachlorocyclohexanes (HCHs) pesticide were evaluated in samples of cowpea grains and dried yam chips obtained from Ile-Ife markets, southwestern Nigeria. The objectives of the study were to establish the presence of the organochlorine pesticide residues in the foodstuffs and also to ascertain whether the residue levels are above their respective permissible levels. Randomly selected samples from highly patronized markets were subjected to standard extraction protocols. The DDT and HCH levels were determined using Gas Chromatography coupled with Electron Capture Detector (GC-ECD). The mean concentration of ϒ-HCH (Lindane) in cowpea grains was 0.085 mg/kg and 0.042 mg/kg in dried yam chips. The ρ,ρ’-DDD concentrations were 0.086 mg/kg and 0.159 mg/kg in cowpea and dried yam chips, respectively. ϒ-HCH detected in all the cowpea samples and 90% in dried yam chips samples were above the recommended EU maximum residue level (MRL) of 0.01 mg/kg. The results of this study indicated that substances that could pose serious health risks were associated, at outrageous levels, with important foodstuffs in Nigerian markets even to the point of sales and consumption. Keywords : Dichlorodiphenyltrichloroethane, hexachlorocyclohexane, pesticide, residue, cowpea grain, yam chip.

Eruca sativa: Benefits as antioxidants source versus risks of already banned pesticides

Eruca sativa (rocket salad) has been intensely consumed all over the world, insomuch as, this work was undertaken to evaluate the antioxidant status and the environmental contamination (positive and negative nutritional contribution) of leaves and stems from this vegetable. Antioxidant capacity of rocket salad was assessed by mean of optical methods, such as the total phenolic content (TPC), reducing power assay and DPPH radical scavenging activity. The extent of the environmental contamination was reached through the quantification of thirteen organochlorine pesticides (OCP) by using gas chromatography coupled with electron-capture detector (GC-ECD) and compound confirmations employing gas chromatography tandem mass-spectrometry (GC-MS/MS). The OCP residues were extracted by using Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) methodology.The extent of the environmental contamination was reached through the quantification of thirteen OCP by using gas chromatography coupled with electron-capture detector (GC-ECD) and compound confirmations employing GC-MS/MS. The OCP residues were extracted by using Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) methodology. This demonstrated that leaves presented more antioxidant activity than stems, emphasizing that leaves contained six times more polyphenolic compounds than stems. In what concerns the OCP occurrence, the average recoveries obtained at the three levels tested (40, 60 and 80 µg kg−1) ranged from 55% to 149% with a relative standard deviation of 11%, (except hexachrorobenzene). Three vegetables samples were collected from supermarkets and analysed following this study. According to data, only one sample achieved 16.21 of β-hexachlorocyclohexane, confirmed by GC-MS/MS. About OCP quantification, the data indicated that only one sample achieved 16.21 µg kg−1 of β-hexachlorocyclohexane, confirmed by GC-MS/MS, being the QuEChERS a good choice for the of OCPs extraction. Furthermore, the leaves consumption guaranty higher levels of antioxidants than stems.

Development and Validation of an Analytical Method for Residues of Organochlorine, Fenopropathrin and Poly Chlorinated Biphnyl Compounds in Fatty Food

A multi-residue method for the quantification of 9 organochlorine pesticides, one syntheticpyrithroid and 7 members of PCBs compounds residues in fish is described. The methodinvolves the application of a modified pesticide manual procedure followed by GC-ECD (GasChromatography coupled with Electron Capture Detector) analysis. The method is validatedaccording to the European Union SANCO/12495/2011 guidelines and Pesticide Manual ofAnalytical methods. The validation levels were 0.01; 0.04; and 0.2 mg /kg for organochlorinesexcept fenopropathrin (a synthetic pyrithroid insecticide) which has been validated at theconcentration of 0.02, 0.08 and 0.4 mg /kg and for PCBs at 0.005, 0.02 and 0.1 mg/kg.Acceptable values were obtained for the following parameters: limit of detection LOD (rangedbetween 0.003-0.009 mg/kg for organochlorine pesticides and 0.002 mg/kg for PCB’s) and limitof quantification (LOQ) (0.005 mg/kg for PCB’s and in the range of 0.01-0.02 mg/kg fororganochlorine compounds). The recovery percentages ranged between 70 and 120%, and themeasurement uncertainty tests was ±40.0%. The method showed to be linear from the LOQ up to the maximum level; 0.1 mg/kg for PCB’s and in the range of 0.2-0.4 mg/kg for organochlorinecompounds. These results demonstrate the applicability of this method in the routine practicefor detecting the residues of such compounds in fatty food.

Optimization of QuEChERS Procedure Coupled to GC-ECD for Organochlorine Pesticide Determination in Carrot Samples

An optimised version of the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method for simultaneous determination of 14 organochlorine pesticides in carrots was developed using gas chromatography coupled with electron-capture detector (GC-ECD) and confirmation by gas chromatography tandem mass spectrometry (GC-MS/MS). A citrate-buffered version of QuEChERS was applied for the extraction of the organochlorine pesticides, and for the extract clean-up, primary secondary amine, octadecyl-bonded silica (C18), magnesium sulphate (MgSO4) and graphitized carbon black were used as sorbents. The GC-ECD determination of the target compounds was achieved in less than 20 min. The limits of detection were below the EU maximum residue limits (MRLs) for carrots, 10–50 μg kg−1, while the limit of quantification did exceed 10 μg kg−1 for hexachlorobenzene (HCB). The introduction of a sonication step was shown to improve the recoveries. The overall average recoveries in carrots, at the four tested levels (60, 80, 100 and 140 μg kg−1), ranged from 66 to 111 % with relative standard deviations in the range of 2–15 % (n = 3) for all analytes, with the exception of HCB. The method has been applied to the analysis of 21 carrot samples from different Portuguese regions, and β-HCH was the pesticide most frequently found, with concentrations oscillating between less than the limit of quantification to 14.6 μg kg−1. Only one sample had a pesticide residue (β-HCH) above the MRL, 14.6 μg kg−1. This methodology combines the advantages of both QuEChERS and GC-ECD, producing a very rapid, sensitive and reliable procedure which can be applied in routine analytical laboratories.