Gas Chromatography With Electron Capture Detection Research Articles

Organochlorine pesticide residues in different fishes and shell fishes collected from the flood plains of Sonargaon upazila, Bangladesh

The present study was carried out to assess the concentrations of organochlorine pesticide residues (DDTs; DDE, DDD, 2,4´-DDT and 4,4´-DDT) in natural fishes and prawn species during rainy-season (June-September, 2014) from flood plains of Sonargaon upazila, Bangladesh. The samples were extracted by Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method and the extracts were cleaned-up by using H2SO4. Analysis of the samples for DDTs residues were carried out by using Gas Chromatograph with Electron Capture Detector (GC-ECD). Controlled fish sample (Cultured Rui fish) was used for the recovery experiments. Percent (%) recovery was found to be in the range of 70%- 113%. The total DDTs contents of the head of different fish and prawn species ranged from 7.53 ± 0.50 ng/g in Jatpunti (P. sophore) to 39.20 ± 3.76 ng/g in Bele (G. giuris) and of the body from 7.55 ± 0.50 ng/g in Jatpunti (P. sophore) to 41.93 ± 3.63 ng/g in Chewa (P. elongatus). While the total DDTs of the total body of seven fish and two prawn species ranged from 4.56 ng/g in Gurachingri (unidentified) to 37.15 ng/g in Chewa (P. elongatus). In the present study, 66.66% samples having value of (DDE + DDD)/DDT, lower than 0.5 ratios indicated the presence of new DDT inputs in the environments of Sonargaon area. The concentrations of total DDTs in all the samples were within the permissible MRL level i.e. for human consumption recommended by FAO-IAEA-WHO. As DDT is a long persistent and bioaccumulative substance in the environment, intake of significant amount of these toxic elements with our diet is a matter of great health concern.
 Bangladesh J. Zool. 47(1): 137-148, 2019

Analytical performance for determination of synthetic pyrethroids residue in Indonesian fermented cocoa using GC-ECD

Pyrethroid insecticides are causing problems for the environment because they are toxic at such small concentrations and very difficult to determine. Characteristics of pyrethroids insecticides include high efficiency, wide spectrum, low biodegradability, and low mammalian and avian toxicity. They also demonstrate strong selectivity for insects and invertebrates. This study presents the results of the analysis conducted on four synthetic pyrethroids in fermented cocoa samples from Indonesia. The pesticides were extracted using acetonitrile and the analysis was carried out by Gas Chromatography with Electron Capture Detector (GC-ECD). Column programming temperature was conducted to get a complete separation. The total operation took less than 10 minutes to separate four standards of synthetic pyrethroids. The synthetic pyrethroids were identified by their retention times and quantified using an external calibration method. The linearity test was carried out for four standard synthetic pyrethroids, namely: lambda-cyhalothrin, permethrin, cypermethrin, and fenvalerate, from 1 μg/kg to 10 μg/kg. The coefficient of correlation (r) was found to be 0.9999; 0.9998; 0.9944; and 0.9999 for lambda-cyhalothrin, permethrin, cypermethrin, and fenvalerate, respectively. The detection limit for synthetic pyrethroids residue was found to be below the EU and Japan regulations, and the method can be applied for the determination of synthetic pyrethroids residues in fermented cocoa.

Assessing and Reporting Household Chemicals as a Novel Tool to Mitigate Pesticide Residues in Spinach (Spinacia oleracea)

Non-selective use of pesticide to increase productivity leaves residues on crops. These pesticides after consumption have a detrimental effect on human health and their intake can lead to various diseases such as kidney damage, neurological disorders, cardiovascular diseases, circulatory and reproductive problems. The recent study was designed to assess the effects of household processing treatments such as acidic solutions (acidic acid and citric acid), alkaline solutions (sodium chloride and sodium carbonate) and biological solutions (radish, ginger, garlic, and lemon extracts) were evaluated for their efficiency for removal of pesticides in spinach by gas chromatography with electron capture detector (GC-ECD). The results showed that pesticide residues were sharply reduced when spinach was exposed to washing treatments. The results showed that the greatest reduction of deltamethrin, cypermethrin, chlorpyrifos and endosulfan with 10% acetic acid was (79.68 ± 0.81%), (89.99 ± 0.12%), (94.21 ± 0.02%) and (70.32 ± 0.25%), respectively of tested washing solutions. The acidic solutions were more effective than alkaline and biological extracts in the removal of pesticide residues. The average reduction in various washing solutions ranged from 10.21 to 79.68%, 22.60 to 89.48%, 22.95 to 94-21% and 11.24–70.32% for the removal of deltamethrin, cypermethrin, chlorpyrifos, and endosulfan, respectively.

Determination of Selected Priority Pesticides in High Water Fruits and Vegetables by Modified QuEChERS and GC-ECD with GC-MS/MS Confirmation.

A modified quick, easy, cheap, efficient, rugged and safe (QuEChERS) method coupled to gas chromatography with electron capture detector (GC-ECD) was developed for simultaneous determination of selected electronegative pesticides in fruits and vegetables with high water content. The chosen compounds are commonly detected in fruit and vegetable crops, and some of their metabolites have even been found in human urine. In addition, some of them are known or suspected carcinogens according to the International Agency for Research of Cancer. Extraction and clean up parameters were optimized, thus the original QuEChERS method was modified to decrease solvent usage, in accordance with ‘green chemistry’ principles. The proposed methodology was validated in terms of selectivity, specificity, linearity, precision and accuracy. The obtained limits of detection (LODs) for all investigated pesticides ranged from 5.6 µg·kg−1 to 15 µg·kg−1 and limits of quantification (LOQs) from 17 µg·kg−1 to 45 µg·kg−1. The obtained data demonstrated the good reproducibility and stability of the procedure in the tested concentration range up to 10 mg·kg−1, with relative standard deviations (RSDs) lower than 10%. Recoveries for spiked pear samples at LOQ level for each pesticide were from 90% to 107% with RSDs lower than 9.6%. The suitability of the developed procedure was tested on various fruit and vegetable samples available on the market at different seasons. The proposed methodology is applicable for detection and monitoring of selected pesticides not only in fruits and vegetables with high water content, but also in samples containing large amounts of pigments and dyes.

Quantification of polybrominated diphenyl ether (PBDE) congeners in wastewater by gas chromatography with electron capture detector (GC-ECD)

This manuscript describes a novel approach for the quantification of PBDEs involving an optimized SPE and GC-ECD method.

Simultaneous Determination of Pyrethroids Residues in Green Tea Leaves, Processed Tea, Tea Infusion and Spent Tea Leaves

A simple method for the simultaneous determination of pyrethroids residues in green tea leaves, processed tea, tea infusion and spent tea leaves is reported. The target analytes were extracted from selected tea matrices with ethyl acetate followed by dispersive solid phase extraction (d-SPE) based on QuEChERS procedure of clean up with primary secondary amine sorbent to remove co-extractives prior to analysis by gas chromatography with electron capture detector (GC-ECD). The recoveries ranged from 76 to 106 per cent with relative standard deviations below 11 per cent. The limits of quantification for pyrethroids ranged from 0.01 to 0.05 μg g−1. The method was successfully applied to analyse residues of pyrethroids insecticides in actual processed tea samples.

Supercritical fluid extraction of pesticides in sediment from the Okavango Delta, Botswana, and determination by gas chromatography with electron capture detection (GC-ECD) and mass spectrometry (GC-MS)

The study reports supercritical fluid extraction (SFE) of pesticides in sediment samples from the Okavango Delta, the headwaters of which originate from Angola and traverse through Namibia into Botswana. An acetone modifier and fractional extraction by pressure ramping gave recoveries ranging from 55 to 86% for the 15 pesticides studied. Hexachlorobenzene (HCB), aldrin and 4, 4-dichlorodiphenyltrichloroethane (4, 4'-DDT) were identified at concentration ranges of 1.1 to 30.3, 0.5 to 15.2 and 1.4 to 55.4 µg/g, respectively by gas chromatography with electron capture detection (GC-ECD) and were unequivocally confirmed by gas chromatography time-of-flight mass spectrometry (GC-ToF-MS). The study indicated an increase of pesticide concentrations in the direction of water flow from the Panhandle (point of entry) to the lower delta. The results show that there are ramifications associated with activities either upstream or downstream; hence close monitoring is required for the long-term preservation of the delta.

Organochlorine Pesticide Residues and Microbiological Quality Assessment of Dried Barb, Puntius sophore, from the Northeastern Part of Bangladesh

The present study was carried out in the northeastern part of Bangladesh to investigate organochlorine pesticide (OCP) residues in and microbiological quality of dried barb (Puntius sophore). Samples were collected from both producers and retailers from December 2016 to April 2017. A control sample was also prepared in the laboratory with the same raw fish used by the producers to compare the results. Gas chromatography with electron capture detector (GC-ECD) was used to detect and quantify OCP residues. Six samples out of 27 (about 22%) were found to be contaminated with OCP residues. Among these six adulterated samples, four were from retailers and two from producers. Only aldrin was detected in four samples, and in the other two samples both aldrin + dieldrin and aldrin + endrin were detected. Aldrin was found in quantities between 0.332 and 0.967 ppm, dieldrin 0.762 ppm, and endrin 0.828 ppm. All these values were much higher than the maximum residual limit (MRL) of 0.1 ppm. Total plate count (TPC) of producer samples ranged from 5.3 ± 0.02 log cfu g−1 to 5.4 ± 0.03 log cfu g−1 and 6.2 ± 0.02 log cfu g−1 to 6.4 ± 0.02 log cfu g−1 for retailer samples and 5.0 ± 0.03 log cfu g−1 to 5.2 ± 0.04 log cfu g−1 for control samples. Fungal count ranged from 3.2 ± 0.04 log cfu g−1 to 3.5 ± 0.04 log cfu g−1, 3.4 ± 0.04 log cfu g−1 to 3.6 ± 0.03 log cfu g−1, and 2.2 ± 0.05 log cfu g−1 to 2.5 ± 0.03 log cfu g−1 for producer, retailer, and control samples, respectively. All the producer and retailer samples and one-third of the control samples were found to be contaminated with Escherichia coli, whereas Salmonella spp. were detected in amounts of 13.3% in producer samples and 20% in retailer samples and none in the control. In case of Vibrio spp., maximum count was found in retailer samples (13.3%), whereas producer and control samples showed none. The findings of the present study show that the presence of pesticides and poor microbiological quality of dried barb are alarming for consumers in Bangladesh and might cause prolonged disease and impending longstanding risk to human health.

Evaluation of 99 Pesticide Residues in Major Agricultural Products from the Western Highlands Zone of Cameroon Using QuEChERS Method Extraction and LC-MS/MS and GC-ECD Analyses.

There is no information available on pesticide residue levels in major food commodities harvested in Cameroon, especially from the western highlands region, the food basket of the country. Hence, this study evaluated the residues of 99 pesticides in 72 samples of 12 agricultural products collected in the region, using QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method extraction, and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography with electron capture detection (GC-ECD). This method was suitable for detecting the targeted compounds: For 81 pesticides by LC-MS/MS, the limit of quantification (LOQ) was between 0.0004 and 0.0537 mg/kg; and for 18 halogenated pesticides by GC-ECD, it ranged from 0.0012 to 0.2180 mg/kg. The residues of 62 pesticides, including 12 banned compounds, were found in the samples. Insecticides (39.7%) were the most prevalent group, with all the samples containing at least one pesticide. Twenty-one pesticides (34.4%) exceeded their European Union maximum residue limits (MRLs) and 22 pesticides (34.4%) were found in all 6 sampling locations. Malathion and p,p′-DDT were the most distributed pesticides, found in almost all the samples and sampling sites. Food items with the highest rates of positive results were chili pepper (23.2%), white pepper (20.2%), kidney beans (17.3%), and soybeans (17.2%). Samples with residues above their MRLs represented 38% of all the positive analyses; chili pepper (6.4%) and kidney beans (5.5%) were found to have the most residues above their MRLs. The most critical food commodities were kidney beans, soybeans, chili pepper, and maize. This data presents scientific evidence that investigation into continuous monitoring and good regulation of pesticide usage in Cameroon is needed, and paves the way for health risks analysis.

Application of a co-polymeric solid phase extraction cartridge to residues containing nitro-organic explosives

A validated solid phase extraction (SPE) cleanup procedure utilizing Bond Elut NEXUS co-polymeric cartridges has been applied to soil and swab samples containing pre- and post-blast residues of nitro-organic explosives. In addition, simulated samples were also processed by SPE to evaluate matrix rejection and interferences. The matrices were extracted with acetone, diluted with deionized water, and processed by SPE. The final extracts were then analyzed by gas chromatography with electron capture detection (GC/ECD) to screen for the compounds of interest, which included ethylene glycol dinitrate (EGDN), dimethyl dinitrobutane (DMDNB), 4-nitrotoluene (4-NT), nitroglycerin (NG), 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT), pentaerythritol tetra-nitrate (PETN), cyclotrimethylene trinitramine (RDX), 2,4,6-trinitrophenylmethylnitramine (tetryl), cyclotetra-methylene tetranitramine (HMX), erythritol tetranitrate (ETN), and cyclotrimethylene trinitrosoamine (R-salt). The expected explosives were detected in 97% of cases after processing through SPE and analysis by GC/ECD. Approximately one-third of the samples that screened positive by ECD were subjected to confirmation testing by gas or liquid chromatography/mass spectrometry (GC/MS or LC/MS). The results from these matrices were compared to results obtained by syringe filtration. SPE produced equal or better results than syringe filtration in both the ECD screening and MS confirmation tests, including the ability to detect higher signals for more explosives in the post-blast residue samples. The confirmation results also show that all of the expected explosives could be confirmed after processing by SPE, whereas only 83% of them were confirmed after syringe filtration. This study demonstrates the successful application of a validated method to the cleanup of organic explosive residues in complex matrices.

Relationship between exposure, body burden and target tissue concentration after oral administration of a low-dose mixture of pyrethroid insecticides in young adult rats

Pyrethroids (PYRs) are synthetic insecticides increasingly used in agricultural and household pest control. Little is known on how the toxicity of highly effective bolus doses of single compounds compares to more realistic scenarios of low-level exposure to PYR mixtures. In this study, we examined a quaternary mixture of two noncyano (tefluthrin, TEF; bifenthrin, BIF) and two cyano (α-cypermethrin, α-CPM; deltamethrin, DTM) PYRs in young adult rats. These compounds are mostly composed of PYR isomers ranking top ten in acute lethality in rats. Concurrently, we administered near-threshold levels of the four PYRs dissolved in corn oil by oral route. Six hours later blood was collected and the liver and cerebellum were dissected out to determine PYR concentrations in these tissues using Gas Chromatography with Electron Capture Detector (GC-ECD). The mixture caused mild-to-moderate changes in non-locomotor behaviors and subcutaneous body temperature (up to +1.2–1.5 °C increase at 2–4 h after dosing, respectively, compared to pre-dosing records). The most toxic PYRs BIF and TEF reached higher concentrations in the cerebellum than the cyano-compounds α-CPM and DTM. In addition, PYR concentrations in the cerebellum were correlated to single compound proportions in the dosing solution and changes in body temperature. Our results suggest that aggregate exposures resulting in a target tissue burden of ∼10−1 nmoles PYR/g may be toxicologically relevant, expanding the evidence on exposure-dose-effect relationships for PYRs, and serving to design convenient pharmacokinetic models for environmentally relevant exposures to PYR mixtures.

Routine Method for the Analysis of Short‐Chain Chlorinated Paraffins in Surface Water and Wastewater

Short‐chain chlorinated paraffins (SCCPs) are persistent compounds that are included in the list of priority substances in the field of water policy of the European Union in 2001. In this paper, a method based on liquid–liquid extraction and gas chromatography with electron capture detection (GC‐ECD) is evaluated to be proposed for the routine analysis of SCCPs in environmental water. Limits of quantification (LOQ) at ng L−1 levels that allow compliance with the maximum admissible level established in the Directive 2013/39/EU, good precision (lower than 11%) and expanded measurement uncertainties (ISO 11352) (lower than 20%) for surface and wastewater samples are obtained. The good agreement between the results found using GC‐ECD and gas chromatography coupled with negative ion chemical ionization mass spectrometry (GC‐NICI‐MS), with relative errors lower than 13%, showed that GC‐ECD is a reliable method to control the presence of SCCPs in environmental water. The method is applied to river and wastewater samples collected in the Metropolitan Area of Barcelona (Spain). SCCPs are found in all the influents of wastewater treatment plants at concentrations ranging from <0.01 (MLOQ) to 3.20 μg L−1, while in the effluents they are detected in 54% of samples at levels below 0.13 μg L−1. SCCPs are not detected at the intake of a drinking water treatment plant that supply water to Barcelona city and only sporadically in the Llobregat River.

An amino-functionalized magnetic framework composite of type Fe3O4-NH2@MIL-101(Cr) for extraction of pyrethroids coupled with GC-ECD.

An amino-functionalized magnetic framework composite of type Fe3O4-NH2@MIL-101(Cr) was synthesized using a solvothermal method. The material was characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption, and magnetometry. The composite combines the advantages of amino-modifiedFe3O4 and MIL-101(Cr). The presence of amino groups facilitates the fairly specific adsorption of pyrethroids. The composite was employed as a sorbent for magnetic solid phase extraction of five pyrethroids from environmental water samples. Following desorption with acidified acetone, the pyrethroids were quantified by gas chromatography with electron capture detection. The detection limits for bifenthrin, fenpropathrin, λ-cyhalothrin, permethrin, and deltamethrin range from 5 to 9pg·mL-1. The method is rapid, accurate, and highly sensitive. The molecular interactions and free binding energies between MIL-101(Cr) and the five pyrethroids were calculated by means of molecular docking. Graphical abstract A novel functionalized magnetic framework composite of typeFe3O4-NH2@MIL-101(Cr) was synthesized. It was applied as a sorbent for magnetic solid phase extraction of pyrethroids prior to their quantitation by gas chromatographywithelectron capture detection. The molecular interactions of analytes and MIL-101(Cr) were studied.

Determination of Target Pesticide Residues in Tropical Fruits Employing Matrix Solid-Phase Dispersion (MSPD) Extraction Followed by High Resolution Gas Chromatography

A simple method based on matrix solid-phase dispersion (MSPD) extraction and gas chromatography with electron-capture detection (GC-ECD) is employed to determine pesticide residues in the following tropical fruits: banana, mango, melon, papaya and pineapple. In the MSPD proposed method, C18, silica gel and ethyl acetate presented the best results in the extraction, clean-up and elution steps, respectively. Spiked blank samples were used to minimize the matrix effect in the chromatographic determination. The validation process was conducted at three different concentration levels of spiked samples (0.50-2.50 µg g-1) in within-a-day and in among days assays. The limits of detection for the pesticides ranged from 4.0 to 23 µg kg-1. The method showed acceptable selectivity, coefficients of correlation higher than 0.997, and recovery between 76-105%. The within-a-day precision was assessed through the relative standard deviation (2.8-19%) for the different levels of spiked samples tested.

Residue behavior of organochlorine pesticides during the production process of yogurt and cheese

The presence of organochlorine pesticides (OCPs) in dairy products can lead to human exposure. This study investigated the behavior of OCP residues in milk during yogurt and cheese production. Gas chromatography with electron-capture detection (GC-ECD) was used to detect α-hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), γ-HCH, g-chlordane, and α-chlordane in fresh milk, yogurt, and cheese. The results showed that fermentation reduced the residual concentration of OCPs in yogurt, with processing factors (PFs) ranging from 0.42 to 0.64. The reductions in residue levels during fermentation were due to the activity of the starter. The cheese making process increased the residual concentration of OCPs in cheese compared to raw milk, with PFs ranging from 2.37 to 4.93. Additionally, milk, yogurt, and cheese samples were purchased from local markets and OCP levels were analyzed. The target OCPs ranged from ND to 16.50 μg/kg in these samples.

Assessment of pesticide residues in vegetables from the Western Usambara and Uruguru Mountains in Tanzania.

Assessment of levels of pesticide residues in vegetables was carried out in some villages in the Western Usambara and Uluguru Mountains of Tanzania where varieties of vegetables are grown. Tomatoes and cabbages were the most popular enterprise grown all year round and therefore were selected as the model crops for this study. Analysis of the cleaned sample extracts on a gas chromatography with electron capture detector (GC-ECD) and confirmation on the Gas chromatography-mass spectrometry (GC-MS) revealed dominance of organochlorine pesticides. Organophosphorous pesticides (parathion and marathion) were only detected in some samples, however, in most cases with higher concentrations compared to organochlorine pesticides. Levels of pesticide residues detected in vegetables were up to: parathion 5.07μg/Kg, marathion 3.73μg/Kg, α-endosulfan 0.32μg/Kg, β-endosulfan 0.53μg/Kg, dieldrin 1.36μg/Kg, γ-HCH 0.25μg/Kg, α-HCH 0.09μg/Kg, and p, p'-DDT 0.64μg/Kg. These results clearly show that vegetables are contaminated with different pesticide residues. However, the total levels of pesticide residues in both tomatoes and cabbages are lower than their respective codex alimentarius maximum residue levels (MRLs). This means that the vegetables produced in the area are suitable for human consumption.

PAHs and DDTs in soil and sediment of inland water bodies of Warsaw city and its surroundings

Concentrations of polycyclic aromatic hydrocarbons (PAHs) and dichlorodiphenyltrichloroethane (DDT) in soil and sediment of inland water bodies in Warsaw and its surroundings, covering an area of 1200km2, were obtained during the work on the ‘Geochemical atlas of Warsaw and Εnvirons, 1:100,000’. Soil samples from a depth of 0–30cm were collected on a regular grid of 1×1km in Warsaw, and 2×2km outside its administrative boundaries. Sediment samples were collected from rivers, streams, ditches, canals, lakes and ponds. The distance between sampling sites in watercourses was 1,5km (within the borders of Warsaw) and 2km (outside the city). Analyses of PAHs and DDT compounds were made by gas chromatography–mass spectrometry (GC-MS), and gas chromatography with electron capture detection (GC-ECD), respectively.Within the borders of Warsaw the soil is characterised by elevated or high levels of PAHs and DDTs. Outside the city, especially to the east, large areas are differentiated by their low concentrations in soil. The highest PAH concentrations (>20,000mg/kg) were found in soil located near railway lines and in industrial and post-industrial areas. The highest contamination by p,p′-DDT and its metabolites is observed in soil of cultivated fields and gardens. The highest concentration of total DDTs (5400mg/kg) was found in allotment gardens in the eastern part of Warsaw. At some places, high predominance of p,p′-DDT concentration over the concentrations of its metabolites was observed, which indicates recent introduction of these compounds into soil. The PAH and DDT concentrations in sediment samples were lower than in soil. High PAH levels were observed mainly in the sediment of ponds and canals, and high DDTs concentrations were found in the sediment of ditches and canals.

Veterinary utility of dried blood spots for analysis of toxic chlorinated hydrocarbons

Dried blood spots (DBS) on filter paper provide a simple and convenient means of collecting, storing and shipping samples for veterinary diagnostics related to toxin exposures. This paper presents validation data on analysis of DBS for chlorinated persistent organic pollutants, specifically 4,4′-dichloro-diphenyl-trichloroethane (4,4′-DDT) and its breakdown product 4,4′-dichlorodiphenyl-dichloroethylene (4,4′-DDE), lindane and a representative polychlorinated biphenyl (PCB) congener PCB-153. Analysis was by gas chromatography with electron capture detection (GC-ECD). The method required one 12.5 mm diameter spot representing application of 50 μL of blood, and working limits of detection (LOD) for each of the compounds was 5 ppb. Data are presented on development and description of the method, assay precision, LOD and quantitation, linearity, accuracy, specificity, effects of long-term storage and ruggedness. The method was also applied to 27 avian DBS, and 4,4′-DDE was detected in the majority of samples.

Determination of iodopropynyl butylcarbamate in cosmetic formulations utilizing pulsed splitless injection, gas chromatography with electron capture detector

Current analytical methodology for iodopropynyl butylcarbamate (IPBC) analysis focuses on the use of liquid chromatography and mass spectrometer (LC–MS), but the high instrumentation and operator investment required has resulted in the need for a cost effective alternative methodology. Past publications investigating gas chromatography with electron capture detector (GC-ECD) for IPBC quantitation proved largely unsuccessful, likely due to the preservatives limited thermal stability. The use of pulsed injection techniques commonly used for trace analysis of thermally labile pharmaceutical compounds was successfully adapted for IPBC analysis and utilizes the selectivity of GC-ECD analysis. System optimization and sample preparation improvements resulted in substantial performance and reproducibility gains. Cosmetic formulations preserved with IPBC (50–100ppm) were solvated in toluene/isopropyl alcohol and quantified over the 0.3–1.3μg/ml calibration range. The methodology was robust (relative standard deviation 4%), accurate (98% recovery), and sensitive (limit of detection 0.25ng/ml) for use in routine testing of cosmetic formulation preservation.

Organochlorine pesticides residues in butter, olive oils and corn oils

Dietary fat and oil is important for many body processes. The present investigation was carried out to determine the concentrations of organochlorine pesticides in butter, olive and corn oil. A total of 125 samples (75 butter, 25 each of olive oil and corn oil) were collected from El Minia Governorate, Egypt. Levels of these compounds were determined by gas chromatography with electron capture detector (GC-ECD). The results indicated that 30.4%(38/125), 24.8%(31/125), 21.6%(27/125), 21.6%(27/125), 16.8%(21/125), 14.4%(18/125), 14.4%(18/125), 12.8%(16/125), 9.6%(12/125), 8.8%(11/125), 8%(10/125), 1.6%(2/125) and 0.8%(1/125) of the examined samples were contaminated with Heptachlor, Endrin, Aldrin, Dichlorodiphenyldichloroethylene(p,p'-DDE), Dichlorodiphenyldichloroethane(p,p'-DDD), Gamma hexachlorocyclohexane(Gamma HCH), Heptachlor epoxide, Dieldrin, Endosulfan, methoxychlor, Alpha hexachlorocyclohexane(Alpha HCH), Delta hexachlorocyclohexane(Delta HCH) and Gamma Chlordane, respectively. None of the examined samples revealed the presence of Dichlorodiphenyltrichloroethane (p,p'-DDT) and 11 samples contained organochlorine residues above European Union maximum residue limits (EU MRL)..