Monitoring of polar pesticides and contaminants in edible oils and nuts by liquid chromatography-tandem mass spectrometry.

A single method was developed for the determination of polar pesticides (fosetyl-Al and its metabolite, phosphonic acid, and ethephon) and environmental contaminants (chlorate and perchlorate) in edible oils and nuts. Two extraction methods based on QuPPe-PO approach (Quick Polar Pesticides Method for products of Plant Origin) were optimized. In oils, a single extraction using water acidified with formic acid (1%) was performed, while in nuts, the clean-up step was modified. C18 was used as sorbent and an extra cleaning step with n-hexane was added. The extracts were analysed by liquid chromatography coupled to a triple quadrupole mass analyser (LC-QqQ-MS/MS). The method was validated and the limit of quantification was 0.01 mg kg-1 for all analyte-matrix combination. Recoveries from 70 to 120%, and intra and inter-day precision values ≤20% were obtained. Forty samples of edible oils and nuts were analysed, detecting phosphonic acid in nuts at concentrations up to 4.6 mg kg-1.

Overview of Analytical Methods for the Determination of Neonicotinoid Pesticides in Honeybee Products and Honeybee.

Neonicotinoid pesticides are widely applied for controlling pests in a variety of agriculture crops. Due to the systemic distribution in plants, neonicotinoid pesticides have been found in nectar and pollen, which are the main source of food for the important pollinator honeybee. The risk of neonicotinoid residues in honeybee products and honeybee has caused great attention since their impacts on the environment, ecology, and food safety issues. These concerns require the accurate and sensitive determination of neonicotinoids and their metabolites in the honeybee products and honeybee. Since the trace residue level of neonicotinoid and the complexity of the samples, analysis of neonicotinoid targets in these important matrices is still a great challenge. The present review provides general overview of analytical methods for the determination of neonicotinoid pesticides and their metabolites in honeybee products and honeybee.

Magnetic amino-functionalized hollow silica-titania microsphere as an efficient sorbent for extraction of pesticides in green and roasted coffee beans.

This study describes the synthesis and application of a magnetic amino-functionalized hollow silica-titania microsphere as a new sorbent for magnetic dispersive micro-solid phase extraction of selected pesticides in coffee bean samples. The sorbent was fully characterized by Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, transition electron microscopy, energy-dispersive X-ray spectroscopy, and vibrating sample magnetometry techniques. Significant extraction parameters affecting the proposed method, such as extraction time, sorbent amount, sample solution pH, salt amount, and desorption conditions (desorption solvent and time) were investigated and optimized. All the figures of merits were validated in coffee bean samples under the matrix-matched calibration method. Linear dynamic ranges were 5-250 µg/kg with the determination coefficients (R2 ) > 0.9980. The limits of detection for the pesticides of chlorpyrifos, malathion, hexaconazole, and atrazine were 1.42, 1.43, 1.35, and 1.33 µg/kg, respectively. Finally, the method was successfully applied for the determination of the pesticides in green and roasted coffee bean samples, and the obtained recoveries were in the range of 74-113% for spiked samples. The prepared sorbent could be used for the magnetic dispersive micro-solid phase extraction of pesticides in the plant-derived food matrix.

Evaluation of biological activities, and exploration on mechanism of action of matrine-cholesterol derivatives.

To develop new potential pesticides, a series of matrine-cholesterol derivatives were prepared by modifications of two non-food bioactive products matrine and cholesterol. Two N-phenylsulfonylmatrinic esters (5i and 5j) showed the most potent insecticidal activity against Mythimna separata Walker. Two N-benzylmatrinic esters (5e and 5g) exhibited the most promising aphicidal activity against Aphis citricola Van der Goot. Especially compound 5e showed good control effects in the greenhouse against A. citricola. Some interesting results of their structure-activity relationships were also observed. By reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time polymerase chain reaction (qRT-PCR) analysis of HMG-CoA reductase in apterous adults of A. citricola, it demonstrated that matrine and cholesterol may be the HMG-CoA reductase inhibitors, and the hydroxyl of cholesterol or the lactam ring of matrine may be important for acting with HMG-CoA reductase in A. citricola.

Phosphorous-enriched knitting aryl network polymer for the rapid and effective adsorption of aromatic compounds.

A phosphorous-enriched knitting aryl network polymer (named as Ph-PPh3-KAP) was fabricated by one-step crosslinking between triphenylphosphine and benzene, with formaldehyde dimethyl acetal as an external crosslinker. The Ph-PPh3-KAP had a large surface area and good physicochemical stability. Its adsorption performance for aromatic organic compounds was evaluated by using some dyes and benzene ring-containing compounds as the model adsorbates. The results exhibited that it had a rapid and effective adsorption for the aromatic organic compounds due to the hydrogen bonding and polar interactions of the Ph-PPh3-KAP with the target compounds. Then, the Ph-PPh3-KAP was explored as the adsorbent for the solid phase extraction of some phenylurea pesticides from lake water, tomato and cucumber samples prior to HPLC analysis. Under optimal conditions, the linear responses of the phenylurea pesticides were 0.1-100 ng mL-1 for lake water and 0.5-100 ng g-1 for cucumber and tomato samples. The limits of detection for the analytes at S/N = 3 were 0.01-0.02 ng mL-1 for lake water and 0.03-0.05 ng g-1 for cucumber and tomato samples. The recoveries were in the range from 80.8% to 118%. The Ph-PPh3-KAP exhibited a great application potential for extraction of aromatic compounds.

[An automated direct immersion solid-phase micro extraction-gas chromatography-mass spectrometry (DI-SPME-GCMS) method for determination pesticides in liquid Chinese herbal health food].

OBJECTIVE: To establish a method to determinate 25 pesticides in liquid health food from Chinese herbal medicines by direct immersion solid phase micro extraction coupled with gas chromatography-mass spectrometry. METHODS: The sample was diluted with ultrapure water, adjusted p H with acetic acid, and then filtered by 0. 45µm filter. The target compounds were extracted and concentrated by the method of on-line immersion solid phase micro extraction( SPME) coupled with 65 µm PDMS/DVB extraction fiber. The sample was separated by GC-MS with TG-5 MS( 30 m × 0. 25 mm ×0. 25 µm) capillary column. RESULTS: The method showed a good linearity R2 above 0. 99 in the range of 20-200 µg/kg for 25 organic phosphorus pesticides analytes with average recovery rates of 77. 9%-97. 9%( n = 6) and the relative standard deviation( RSD)within 1. 72%-13. 57%. The limits of detection( LOD) were between 3-10 µg/kg. CONCLUSION: The method is simple, accurate, sensitive and very environmental friendly. It is suitable for the determination of 25 pesticides in liquid health food from Chinese herbal medicines.

Toxic effects of Solanum xanthocarpum Sch &Wendle against Helicoverpa armigera (Hub.), Culex quinquefasciatus (Say.) and Eisenia fetida (Savigny, 1826).

Many commercially available agro and household chemicals are used as pesticides, repellents, and growth inhibitors against insect pests. The repeated uses of these chemicals against insect pests have caused the development of resistance in them; they also cause ill effects on nontarget organisms. The present study was aimed to evaluate the antifeedant, larvicidal, pupicidal, and biochemical effects of the solvent extracts of Solanum xanthocarpum against third instar larvae of Helicoverpa armigera. Hexane, chloroform and ethyl acetate extracts were subjected to phytochemical analysis. The results revealed the presence of terpenoids, flavonoid, and quinone. Maximum antifeedant activity of 72.30% was recorded in chloroform extract followed by hexane (69.02%) and ethyl acetate (57.40%) extracts against H. armigera. Chloroform extracts of S. xanthocarpum showed more than 60% larvicidal and pupicidal activity against H. armigera. The effective chloroform extract was fractionated with increasing polarity of solvent system (hexane, chloroform, and ethyl acetate extracts). Based on the TLC profile, nine major fractions were isolated. The fourth fraction showed higher antifeedant, larvicidal, and pupicidal activity against H. armigera. The effective fraction reduced the hemolymph and gut protein concentration in a concentration-dependent manner (r 2 0.99). The effective fraction 4 showed 100% larvicidal activity at 500 ppm concentration with LC50 value of 227.95 ppm. The fourth fraction did not show any toxic symptom or mortality of earthworm. Based on these results, this effective fraction could be used in the development of a pesticide formulation to control insect.

Assessing the effectiveness of a three-stage on-farm biobed in treating pesticide contaminated wastewater.

Agricultural point source pesticide pollution arising from contaminated machinery washings and accidental spillages pose a significant threat to river water and groundwater quality. In this study, we assess the effectiveness of a three-stage on-farm biobed for treating pesticide contaminated wastewater from a large (20 km(2)) commercial arable estate. The facility consisted of an enclosed machinery wash-down unit (stage 1), a 49 m(2) lined compost-straw-topsoil biobed (stage 2), and a 200 m(2) drainage field with a trickle irrigation system (stage 3). Pesticide concentrations were analysed in water samples collected fortnightly between November 2013 and November 2015 from the biobed input and output sumps and from 20 porous pots buried at 45 cm and 90 cm depth within the drainage field. The results revealed that the biobed removed 68-98% of individual pesticides within the contaminated washings, with mean total pesticide concentrations reducing by 91.6% between the biobed input and output sumps. Drainage field irrigation removed a further 68-99% of individual pesticides, with total mean pesticide concentrations reducing by 98.4% and 97.2% in the 45 cm and 90 cm depth porous pots, respectively. The average total pesticide concentration at 45 cm depth in the drainage field (57 µg L(-1)) was 760 times lower than the mean concentration recorded in the input sump (43,334 µg L(-1)). There was no evidence of seasonality in the efficiency of biobed pesticide removal, nor was there evidence of a decline in removal efficiency over the two-year monitoring period. However, higher mean total pesticide concentrations at 90 cm (102 µg L(-1)) relative to 45 cm (57 µg L(-1)) depth indicated an accumulation of pesticide residues deeper within the soil profile. Overall, the results presented here demonstrate that a three-stage biobed can successfully reduce pesticide pollution risk from contaminated machinery washings on a commercial farm.

Aqueous ozone solutions for pesticide removal from potatoes.

The presence of pesticide residues in potatoes is of concern because of the potential impact to human health due to the high consumption of this vegetable. In this study, aqueous solutions with and without ozone saturation as postharvest wash treatment at pH 4.0, 7.0, and 9.0 were tested to remove chlorothalonil from potatoes. The method used for pesticide analysis has been validated, presenting recovery values of 94-103%, with variations in the repeatability coefficients of ≤10.6%, and a quantification limit of 0.05 mg kg-1 Regardless of pH, treatment with aqueous ozone solutions removed 70-76% of the pesticide present in the potato. In the no-ozone treatments, the percentage average removal of chlorothalonil residues in potatoes was only 36%. Over 24 days of storage, the quality of potatoes washed with aqueous ozone solutions was not significantly different from those washed with pure water.

Solid-phase purification and extraction for the determination of trace neonicotinoid pesticides in tea infusion.

An analytical protocol that includes solid-phase purification and extraction is successfully developed for the determination of trace neonicotinoid pesticides in tea infusion. The method consists of a purification on amino-functionalized mesoporous silica SBA-15 followed by a solid-phase extraction based on graphene oxide before ultra high performance liquid chromatography with tandem mass spectrometry analysis. Parameters that significantly affected the extraction of the neonicotinoids onto graphene oxide, such as the amount of adsorbent, extraction time, pH, elution solvent, etc. were optimized. The amino-functionalized mesoporous silica SBA-15 has been proved to be an efficient adsorbent for removal of polyphenols especially catechins from tea infusion. Graphene oxide exhibits a very rapid adsorption rate (within 10 min) and high adsorption capacities for neonicotinoids at low initial concentration (0.01-0.5 mg/L). The analysis method gave a good determination coefficient (r(2) > 0.99) for each pesticide and high recoveries in the range of 72.2-95.0%. Powder X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and UV-vis spectroscopy were utilized to identify the structure and morphology of graphene oxide. The adsorption driving force of neonicotinoids on graphene oxide mainly depends on π-π electron donor-acceptor interaction and electrostatic interaction.

Challenging conventional risk assessment with respect to human exposure to multiple food contaminants in food: A case study using maize.

Mycotoxins and heavy metals are ubiquitous in the environment and contaminate many foods. The widespread use of pesticides in crop production to control disease contributes further to the chemical contamination of foods. Thus multiple chemical contaminants threaten the safety of many food commodities; hence the present study used maize as a model crop to identify the severity in terms of human exposure when multiple contaminants are present. High Content Analysis (HCA) measuring multiple endpoints was used to determine cytotoxicity of complex mixtures of mycotoxins, heavy metals and pesticides. Endpoints included nuclear intensity (NI), nuclear area (NA), plasma membrane permeability (PMP), mitochondrial membrane potential (MMP) and mitochondrial mass (MM). At concentrations representing legal limits of each individual contaminant in maize (3ng/ml ochratoxin A (OTA), 1µg/ml fumonisin B1 (FB1), 2ng/ml aflatoxin B1 (AFB1), 100ng/ml cadmium (Cd), 150ng/ml arsenic (As), 50ng/ml chlorpyrifos (CP) and 5µg/ml pirimiphos methyl (PM), the mixtures (tertiary mycotoxins plus Cd/As) and (tertiary mycotoxins plus Cd/As/CP/PM) were cytotoxic for NA and MM endpoints with a difference of up to 13.6% (p≤0.0001) and 12% (p≤0.0001) respectively from control values. The most cytotoxic mixture was (tertiary mycotoxins plus Cd/As/CP/PM) across all 4 endpoints (NA, NI, MM and MMP) with increases up to 61.3%, 23.0%, 61.4% and 36.3% (p≤0.0001) respectively. Synergy was evident for two endpoints (NI and MM) at concentrations contaminating maize above legal limits, with differences between expected and measured values of (6.2-12.4% (p≤0.05-p≤0.001) and 4.5-12.3% (p≤0.05-p≤0.001) for NI and MM, respectively. The study introduces for the first time, a holistic approach to identify the impact in terms of toxicity to humans when multiple chemical contaminants are present in foodstuffs. Governmental regulatory bodies must begin to contemplate how to safeguard the population when such mixtures of contaminants are found in foods and this study starts to address this critical issue.

Bioremediation of soils contaminated with polycyclic aromatic hydrocarbons, petroleum, pesticides, chlorophenols and heavy metals by composting: Applications, microbes and future research needs.

Increasing soil pollution problems have caused world-wide concerns. Large numbers of contaminants such as polycyclic aromatic hydrocarbons (PAHs), petroleum and related products, pesticides, chlorophenols and heavy metals enter the soil, posing a huge threat to human health and natural ecosystem. Chemical and physical technologies for soil remediation are either incompetent or too costly. Composting or compost addition can simultaneously increase soil organic matter content and soil fertility besides bioremediation, and thus is believed to be one of the most cost-effective methods for soil remediation. This paper reviews the application of composting/compost for soil bioremediation, and further provides a critical view on the effects of this technology on microbial aspects in contaminated soils. This review also discusses the future research needs for contaminated soils.

Removal of PAHs and pesticides from polluted soils by enhanced electrokinetic-Fenton treatment.

In this study, electrokinetic-Fenton treatment was used to remediate a soil polluted with PAHs and the pesticide pyrimethanil. Recently, this treatment has emerged as an interesting alternative to conventional soil treatments due to its peculiar advantages, namely the capability of treating fine and low-permeability materials, as well as that of achieving a high yield in the removals of salt content and inorganic and organic pollutants. In a standard electrokinetic-Fenton treatment, the maximum degradation of the pollutant load achieved was 67%, due to the precipitation of the metals near the cathode chamber that reduces the electro-osmotic flow of the system and thus the efficiency of the treatment. To overcome this problem, different complexing agents and pH control in the cathode chamber were evaluated to increase the electro-osmotic flux as well as to render easier the solubilization of the metal species present in the soil. Four complexing agents (ascorbic acid, citric acid, oxalic acid and ethylenediaminetetraacetic acid) in the Fenton-like treatment were evaluated. Results revealed the citric acid as the most suitable complexing agent. Thereby its efficiency was tested as pH controller by flushing it in the cathode chamber (pH 2 and 5). For the latter treatments, near total degradation was achieved after 27 d. Finally, phytotoxicity tests for polluted and treated samples were carried out. The high germination levels of the soil treated under enhanced conditions concluded that nearly complete restoration was achieved.

Simultaneous and enantioselective determination of cis-epoxiconazole and indoxacarb residues in various teas, tea infusion and soil samples by chiral high performance liquid chromatography coupled with tandem quadrupole-time-of-flight mass spectrometry.

A novel and sensitive method for simultaneous enantiomeric analysis of two pesticides-cis-epoxiconazole and indoxacarb-in various teas, black tea infusion, and soil samples has been developed. The samples were initially subjected to acetonitrile extraction followed by cleanup using lab-made florisil/graphitized carbon black mixed solid phase extraction (SPE) column (for the different teas and soil samples) and a BondElut C18-SPE column (for the black tea infusion samples). Separation of the analytes was performed on a chiral stationary phase using high performance liquid chromatography (HPLC) under a reversed-phase isocratic elution mode followed by tandem quadrupole time-of-flight mass spectrometry (Q-TOF/MS) detection. The mobile phase components, mobile phase ratios, flow rates, column temperatures, and MS parameters were all optimized to reach high sensitivity and selectivity, good peak shape, and satisfactory resolution. The performance of the method was evaluated based on the sensitivity, linearity, accuracy, precision, and matrix effects. Under optimal conditions, for the various teas (green tea, black tea, and puer tea), fresh tea leaf, soil and black tea infusion samples spiked at low, medium, and high levels, the mean recoveries for the four enantiomers ranged from 61.0% to 129.7% with most relative standard deviations (RSDs) being 17.1% or below. Good linearity can be achieved with regression coefficients (R) of 0.9915 or above for all target enantiomers, and matrix-matched calibration concentration ranging from 5.0 to 1000µg/L. The limits of detection (LODs) for all four target enantiomers were 1.4µg/kg or below in the different teas and soil samples and 0.05µg/kg or below in the black tea infusion, whereas the limits of quantification (LOQs) for those did not exceed 5.0µg/kg and 0.2µg/L, respectively. The proposed method is convenient and reliable and has been applied to real tea samples screening. It has also been extended for studies on the degradation kinetics and environmental behaviors in the field trials, providing additional information for reliable risk assessment of these chiral pesticides.

Ultrasound-assisted dispersive liquid-liquid microextraction based on the solidification of a floating organic droplet followed by gas chromatography for the determination of eight pyrethroid pesticides in tea samples.

A novel ultrasound-assisted dispersive liquid-liquid microextraction based on solidification of floating organic droplet method (UA-DLLME-SFO) combined with gas chromatography (GC) was developed for the determination of eight pyrethroid pesticides in tea for the first time. After ultrasound and centrifugation, 1-dodecanol and ethanol was used as the extraction and dispersive solvent, respectively. A series of parameters, including extraction solvent and volume, dispersive solvent and volume, extraction time, pH, and ultrasonic time influencing the microextraction efficiency were systematically investigated. Under the optimal conditions, the enrichment factors (EFs) were from 292 to 883 for the eight analytes. The linear ranges for the analytes were from 5 to 100µg/kg. The method recoveries ranged from 92.1% to 99.6%, with the corresponding RSDs less than 6.0%. The developed method was considered to be simple, fast, and precise to satisfy the requirements of the residual analysis of pyrethroid pesticides.

Poly(ionic liquid) immobilized magnetic nanoparticles as new adsorbent for extraction and enrichment of organophosphorus pesticides from tea drinks.

New poly(ionic liquid) immobilized magnetic nanoparticles (PIL-MNPs) were synthesized via co-polymerization of 1-vinyl-3-hexylimidazolium-based ionic liquid and vinyl-modified magnetic particles and were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and magnetic measurements. The PIL-MNPs were utilized as adsorbent phases in magnetic solid-phase extraction (MSPE). The extraction and enrichment efficiency were evaluated by using four organophosphorus pesticides (parathion, fenthion, phoxim and temephos) as test analytes. Various parameters, such as amount of adsorbent, adsorption time, desorption solvent and time, and ionic strength were investigated. The proposed method showed good linearity for the analytes in the concentration range of 1-200µgL(-1) with a correlation coefficient (R)>0.9963. Low limit of detection of 0.01µgL(-1) and high enrichment factors ranging from 84 to 161 were achieved. The proposed method has been successfully used to determine organophosphorus pesticides from three tea drink samples with satisfactory recovery of 81.4-112.6% and RSDs of 4.5-11.3%. The PIL-MNP adsorbent can be reused for 20 times without a noticeable decrease in extraction efficiency.

In situ vadose zone bioremediation.

Contamination of the vadose zone with various pollutants is a world-wide problem, and often technical or economic constraints impose remediation without excavation. In situ bioremediation in the vadose zone by bioventing has become a standard remediation technology for light spilled petroleum products. In this review, focus is given on new in situ bioremediation strategies in the vadose zone targeting a variety of other pollutants such as perchlorate, nitrate, uranium, chromium, halogenated solvents, explosives and pesticides. The techniques for biostimulation of either oxidative or reductive degradation pathways are presented, and biotransformations to immobile pollutants are discussed in cases of non-degradable pollutants. Furthermore, research on natural attenuation in the vadose zone is presented.

Fast ultrasound-assisted extraction followed by capillary gas chromatography combined with nitrogen-phosphorous selective detector for the trace determination of tebuconazole in garlic, soil and water samples.

A fast and an efficient ultrasound-assisted extraction technique using a lower density extraction solvent than water was developed for the trace-level determination of tebuconazole in garlic, soil and water samples followed by capillary gas chromatography combined with nitrogen-phosphorous selective detector (GC-NPD). In this approach, ultrasound radiation was applied to accelerate the emulsification of the ethyl acetate in aqueous samples to enhance the extraction efficiency of tebuconazole without requiring extra partitioning or cleaning, and the use of capillary GC-NPD was a more sensitive detection technique for organonitrogen pesticides. The experimental results indicate an excellent linear relationship between peak area and concentration obtained in the range 1-50 µg/kg or µg/L. The limit of detection (S/N, 3 ± 0.5) and limit of quantification (S/N, 7.5 ± 2.5) were obtained in the range 0.2-3 and 1-10 µg/kg or µg/L. Good spiked recoveries were achieved from ranges 95.55-101.26%, 96.28-99.33% and 95.04-105.15% in garlic, Nanivaliyal soil and Par River water, respectively, at levels 5 and 20 µg/kg or µg/L, and the method precision (% RSD) was ≤5%. Our results demonstrate that the proposed technique is a viable alternative for the determination of tebuconazole in complex samples.

Multi-residue method for the determination of 57 persistent organic pollutants in human milk and colostrum using a QuEChERS-based extraction procedure.

Human breast milk represents the best choice for the nutrition of infants. However, in addition to containing beneficial nutrients and antibodies, it can also be considered the best indicator of infant exposure to contaminants. We developed a multi-residue method using a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure and capillary gas chromatography-triple quadrupole mass spectrometry for the determination of 57 persistent organic pollutants, including 23 organochlorine pesticides, 18 polychlorinated biphenyl (PCB) congeners, and 16 polycyclic aromatic hydrocarbons in human milk and colostrum samples. We have used primary secondary amine in the clean-up step as it gave a more efficient separation of the analytes from fat and superior removal of the co-extracted substances compared with gel permeation chromatography. No significant matrix effect was observed for the tested pollutants, and therefore matrix-matched calibration was not necessary. The average recoveries from spiked samples were in the range of 74.8-113.0 %. The precision was satisfactory, with relative standard deviations below 16 %, while values of 0.1-0.4 µg L(-1) were established as the limit of quantification for all the target analytes (0.05 and 100 µg L(-1)). The method was successfully applied to the analysis of 18 human colostrum and 23 mature milk samples. All the samples tested were positive for at least nine different residues, with some samples containing up to 24 contaminants. Remarkably, the contaminants hexachlorobenzene, p,p'-DDE, PCB 138, PCB 180, phenanthrene, fluoranthene, and pyrene were present in 100 % of the colostrum and mature milk samples analyzed.

Validation of one-step cleanup and separation method of polychlorinated biphenyls, organochlorine pesticides, and polycyclic aromatic hydrocarbons from atmospheric gas- and particle-phase samples.

A one-step cleanup method is described for the determination of PAHs, PCBs and OCPs in air (gas and particulate phase) samples. Analytes were extracted from ambient air samples using soxhlet extraction with a solvent mixture of dichloromethane and petroleum ether (1:4) for 24h. They were concentrated, separated and fractionated on a florisil and alumina column. The amounts of florisil (1g or 2g) with/without alumina were tested in the cleanup column. The study systematically investigated the effects of solvent types, and the amounts of florisil and alumina, on the performance of the cleanup process. The first fraction was eluted with 25 mL hexane, and analyzed for PCBs. The second fraction was collected via 40 mL hexane-ethyl acetate (1:1) solvent mixture, and analyzed for OCPs and PAHs. The optimized method yielded average recoveries between 88% and 99% for PCBs; 56% and 118% for PAHs; and 51% and 128% for OCPs. Other validation parameters were also investigated, such as MDL, LOQ, linear range, sensitivity (r(2)). An oven-program optimization and adjustment of GC-MS were performed. For internal quality control, surrogate recoveries and field blanks values were calculated. External calibration curves were prepared for PAHs, and internal calibration curves were preferred for OCP and PCBs.