Presence of pesticides in breast milk and infants’ formulae in Himachal Pradesh,India

This study documents the levels of pesticide residues in milk samples of mothers from Himachal Pradesh, India, and time trend comparison of pesticide load based on various studies conducted around the world. The regional difference in xenobiotic levels of breast milk varied with demographic characteristics of mothers and altitudinal variations. The single or multiple pesticides contamination of p,p′-DDE, p,p′-DDT and chlorpyrifos was revealed in 27.45% mothers’ milk samples. Among these p,p′-DDE was the major contaminant found in 26.79% samples followed by p,p′-DDT (1.31%) and chlorpyrifos (0.65%). However, residues of other 26 pesticides comprising organochlorines, organophosphorus and synthetic pyrethroids included in this study were below detectable limit (BDL). The determination of a low DDT/DDE ratio (0.050) indicated past exposure of mothers to DDT from the environment. The pesticide residues level in samples drawn from 14 branded infant formulae was BDL. The calculated infants’ daily intake (DI) of DDT was 0.0015 mg kg^?1 body weight per day compared with a decade-old study (0.021 mg kg^?1 body weight per day) suggesting a sharp decline in the residue levels of these pesticides in the Himalayan region. The trend comparison with past studies conducted around the world indicate a decline in the levels of organochlorine pesticide residues in mothers’ milk and further drop of DI in infants. However, such comparisons confer very limited utilisation of data generated on pesticide load in mothers’ milk and simultaneous infants’ DI due to lack of proper research protocol.     

Characterization of three Aroclor mixtures using a new cyanobiphenyl stationary phase

The retention characteristics of all 209 polychlorinated biphenyl (PCB) congeners were determined on a new p,p-cyanobiphenyl stationary phase using gas chromatography with electron capture detection (GC-ECD). Response factors were determined relative to decachlorobiphenyl, PCB 209. Several congeners that coelute on the phases routinely used for PCB analysis are separated on this phase, including the hexachlorobiphenyls 138, 163, and 164. The p,p-cyanobiphenyl stationary phase exhibits altered retention for planar congeners, such that the toxic coplanar PCBs 77, 126, and 169 are eluted free from interference. Of the 209 congeners, 61 were separated using the p,p-cyanobiphenyl phase in conjunction with GC-ECD. When analyzed by gas chromatography with mass selective detection (GC-MSD), the number of congeners determined increased to 133. Therefore GC-MSD was used with the p,p-cyanobiphenyl phase to characterize three PCB mixtures: Aroclor 1242, Aroclor 1254, and Aroclor 1260.     

Improved analytical procedure for determination of chlorinated pesticide residues in human serum using solid phase disc extraction (SPDE), single-step clean-up and gas chromatography

Summary An improved analytical methodology based on solid-phase disc extraction (SPDE) and a single-step clean-up on Florisil is proposed for a large number of organochlorine pesticide residues in serum. Extraction was performed following denaturation of proteins with formic acid after it was shown that it has no degradation effect on targeted analytes (α, β, γ-HCH isomers, HCB, DDT with its 5 analogues, endrin, aldrin, dieldrin, alachlor; heptachlor, heptachlorepaxide, α, β-endosulphan, endosulphansulphate, methoxychlor and mirex). Determination and quantification were by GC-ECD and GC-MS on two different, analytical capillary-columns using PCNB (pentachlonitrobenzene) and PCB 190 internal standards. Recoveries and limits of detection determined on pooled serum ranged 54–102% (for medium spiking level) and 10–50 pg ml⁻¹ serum respectively. Twenty-one individuals serum samples from the University Hospital of Antwerp were analysed and results were related to the ages of the donors. For compounds not detected by GC-MS, eventual coelution with PCBs in GC-ECD analysis was studied.     

A New Method for the Measurement of Airborne Formaldehyde Using Derivatization with 3,5-Bis(Trifluoromethyl) Phenylhydrazine and Analysis by GC-ECD and GC-MS/SIM

Abstract

A new method was developed and described for the measurement of airborne formaldehyde using derivatization with 3,5-bis(trifluoromethyl)phenylhydrazine (TFMPH) coated onto silica solid phase extraction cartridges. Analysis by GC-ECD provides a detection limit of 74 ng formaldehyde per sample. A field study was conducted to compare the use of TFMPH to 2,4-dinitrophenylhydrazine (DNPH) and NIOSH method 3500 (chromotropic acid, CTA). Samples were collected from indoor and outdoor environments known or suspected to contain formaldehyde. Use of TFMPH with GC-ECD analysis correlates well with both methods (R²=0.93, slope=1.07 vs. DNPH; R²=0.99, slope=1.06 vs. CTA). Spiked samples were shown to be stable at least 7 days when stored at –20 °C. Analysis of samples by GC-MS with selected ion monitoring (GC-MS/SIM) also proved feasible. Laboratory and field results show the use of TFMPH to be viable for quantifying airborne formaldehyde in occupational and environmental samples.     

Automated sample clean-up and fractionation of organochlorine pesticides and polychlorinated biphenyls in human milk using NP-HPLC with column-switching

A method has been developed for the automated sample pretreatment of organochlorine pesticides (OCP's) and polychlorinated biphenyls (PCB's) in extracts of human milk. This work was part of a regular monitoring program presently carried out at our institute. In this program several hundreds of human milk samples have to be analyzed for the occurrence of PCB's and OCP's. With a normal bore straight phase HPLC system, utilizing column switching we are able to separate the fat from the compounds of interest and, moreover, complete separation of the PCB fraction from the OCP's can be achieved. Under the conditions used to separate the PCB fraction from intefering OCP's column-switching is essential since the retention times for the OCP's vary from 4 minutes for hexachlorobenzene (HCB) to more than 2 hours for dieldrin. 1 ml of an extract containing 45 mg of fat is injected on the first (pre)column, the fat is retained on this column and the early eluting HCB, the PCB fraction, and the DDT complex are transferred to the second (analytical) column. Compounds eluting later than p,p′-DDT are collected directly from the precolumn. Meanwhile, the PCB fraction is separated from the rest of the OCP's on the analytical column. Contrary to conventional gravity-controlled chromatography or solid phase extraction the clean-up process can be monitored on-line by UV-detection, thus rendering a fast and reliable optimization of the system. The OCP-fractions collected from the LC are pooled before they are transferred to a high resolution gas chromatograph equipped with a large volume option. The PCB-fraction is injected directly in a HRGC equipped with a concurrent solvent evaporation injection device. The limits of detection for the OCP's (HCB, α-,β- and γ-HCH, β-Hepo (heptachlorepoxide), dieldrin, p,p′-DDE, o,p′-DDT p,p′-DDT and TDE) and the PCB's investigated are at sub-ppb level (fat basis); the recoveries vary from 80 to 100%.     

Persistent organochlorines in human breast milk from Al-Sharkia Governorate,Egypt

In the present study, 23 human breast milk samples were collected in January 2009 from Fakous city, Al-Sharkia Governorate, Egypt. The samples were analysed for organochlorine pesticides such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, α, β, and γ-hexachlorocyclohexane (HCH) isomers. The average concentrations of ΣHCHs and ΣDDTs were 225 and 1315?ng?g^?1 lipid respectively. There was no significant difference between the levels of OCP and mother age, while there was a significant difference and correlation between the levels of OCP and the number of times the mother had breast fed (primiparae and multiparae) (p?<?0.05). The results suggested that DDT is still entering the environment depending on the observed ratio of DDE/DDT. The levels of OCP in human milk elucidated that we need to do more regular pollutant monitoring programs.     

Simultaneous detection of A and B trichothecenes by gas chromatography with flame ionization or mass selective detection

A clean-up cartridge consisting of ammonium sulfate, celite, alumina, charcoal and C18 was developed for the simultaneous detection of A and B type trichothecenes, namely 4,15-diacetoxy-scirpenol, T2-toxin, deoxynivalenol (DON) and nivalenol (NIV). After derivatization with N,N-dimethyl-trimethylsilyl-carbamate, the purified extracts were analyzed by gas chromatography with flame ionization (GC-FID) or mass selective detection (GC-MSD). Using this cartridge, no further sample clean-up steps are required that makes the developed method time and cost effective. The method is easy to implement; no special experience or instrumentation is required. The limits of detection in semolina and corn grits ranged from 0.30 to 0.47 mg kg⁻¹ for GC-FID and from 0.05 to 0.35 mg kg⁻¹ for GC-MSD. Corn gluten feed (CGF) samples were analyzed as well, for 4,15-diacetoxy-scirpenol and T2 toxin, with a limit of detection of 0.23 and 0.14 mg kg⁻¹, respectively.     

A comparison of a gas chromatographic with electron-capture detection and a gas chromatographic with mass spectrometric detection screening methods for the analysis of famoxadone in grapes and wines

Famoxadone is a recent oxazolidinedione fungicide widely used in viticulture and in Integrated Pest Management strategies. In this work, after a simple and fast liquid-liquid extraction (LLE), two new gas chromatographic methods were developed to analyze famoxadone residues in grapes and wines, one with electron-capture detection (GC-ECD) and the other with mass spectrometry (GC-MS). Global uncertainties for validation parameters of both methods were compared. Limits of detection (LODs) were 0.06 and 0.02 mg/L, precision was not above 11.7 and 6.8% and recoveries were, on average, 103%+/-12 and 96%+/-12, respectively, for the GC-ECD and GC-MS methods. Similar expanded uncertainties in the range from 0.25 to 1.00 mg/L were below 35%, with increasing values for lower levels of famoxadone. GC-MS method had a lower LOD and a lower uncertainty if compared with the GC-ECD method.     

Optimization of QuEChERS method for the analysis of organochlorine pesticides in soils with diverse organic matter

A QuEChERS method has been developed for the determination of 14 organochlorine pesticides in 14 soils from different Portuguese regions with wide range composition. The extracts were analysed by GC-ECD (where GC-ECD is gas chromatography-electron-capture detector) and confirmed by GC-MS/MS (where MS/MS is tandem mass spectrometry). The organic matter content is a key factor in the process efficiency. An optimization was carried out according to soils organic carbon level, divided in two groups: HS (organic carbon >2.3%) and LS (organic carbon <2.3%). The method was validated through linearity, recovery, precision and accuracy studies. The quantification was carried out using a matrix-matched calibration to minimize the existence of the matrix effect. Acceptable recoveries were obtained (70-120%) with a relative standard deviation of ≤16% for the three levels of contamination. The ranges of the limits of detection and of the limits of quantification in soils HS were from 3.42 to 23.77 μg kg(-1) and from 11.41 to 79.23 μg kg(-1), respectively. For LS soils, the limits of detection ranged from 6.11 to 14.78 μg kg(-1) and the limits of quantification from 20.37 to 49.27 μg kg(-1) . In the 14 collected soil samples only one showed a residue of dieldrin (45.36 μg kg(-1) ) above the limit of quantification. This methodology combines the advantages of QuEChERS, GC-ECD detection and GC-MS/MS confirmation producing a very rapid, sensitive and reliable procedure which can be applied in routine analytical laboratories.     

Research in environmental pollution

Summary One non-o,o-Cl and 12 mono-o,o-Cl substituted PCB congeners were identified in Hessian milk by GC-MS. For risk and hazard assessment the concentrations of these analysed PCB congeners were transformed into the corresponding TCDD e2qu ivalents (TE). It was found that the concentrations of the analysed coplanar PCB congeners in Hessian milk expressed in TE are by a factor of about 16 higher than that of the polychlorinated dibenzo-p-dioxins (PCDD's) and dibenzofurans (PCDF's) in milk.Part V see [2]     

Analytical method for assessing exposure of greenhouse applicators to procymidone by gas chromatography and whole body dosimetry

Summary An analytical method for the determination of the potential and actual exposure of agricultural workers to procymidone has been developed. The methodology is based on the whole body technique, using Tyvek Pro-Tech and Sontara as sampling media, and uses hexane extraction, GC-ECD analysis and GC-MSD confirmation. The validation of the analytical method has been carried out incorporating the matrix of coverall in all steps when calculating parameters such as retention time window, limits of detection and quantification, linear ranges and precision. A field sampling strategy has also been developed and the method has been applied to the evaluation of the potential and actual dermal exposure of an applicator and an assistant in normal working conditions.     

Headspace single-drop microextraction coupled with gas chromatography electron capture detection of butanone derivative for determination of iodine in milk powder and urine

A new detection method using headspace single-drop microextraction (HS-SDME) coupled to gas chromatography (GC) was established to determine the iodine in milk powder and urine. The derivative from the reaction between iodine and butanone in the acidic media was extracted into a micro-drop then determined by GC-ECD. With the optimisation of HS-SDME and derivatisation, the calibration curve showed good linearity within the range of 0.004–0.1 μg mL^?1 (0.004–0.1 μg g^?1) (R ² = 0.9991), and the limits of detection for milk powder and urine were 0.0018 μg g^?1 and 0.36 μg L^?1, respectively. The mean recoveries of milk powder and urine were 90.0–107 % and 89.4–101 % with mean RSD of 1.7–3.4 % and 2.7–3.3 %, respectively. This detection method affords a number of advantages, such as being simple, rapid, and inexpensive, with low organic solvent consumption, and is remarkably free from interference effects, rendering it an efficient method for the determination of iodine in milk powder and urine samples.     

Determination of Organochlorine Pesticides and Polychlorinated Biphenyls Residues in Municipal Solid Waste Compost by Gas Chromatography with Electron−Capture Detection

A simple and efficient method for the simultaneous gas chromatographic determination of ten organochlorine pesticides (α-HCH, β-HCH, γ-HCH, p,p’-DDT, o,p’-DDT, p,p’-DDD, p,p’-DDE, aldrin, endrin, and dieldrin) and six congeners of PCBs (PCB 28, 52, 118, 138, 153, and 180) in municipal solid waste compost is described. The procedure involves a solid-phase dispersion matrix using celite as dispersant sorbent, alumina as clean up sorbent and hexane-dichloromethane (7:3, v/v) mixture as eluting solvent. An additional purification step with copper was necessary to eliminate sulphur. Analysis of the sample was performed by GC-ECD. The method was validated with fortified samples at two concentration levels (0.025 and 0.05 mg kg^?1). Average recovery ranged from 77 to 121% with relative standard deviation between 1 and 18%. The detection limits, which ranged from 0.003 to 0.01 mg kg^?1, were lower than those established by the Baden–Württemberg directive (0.033 mg kg^?1).     

Interlaboratory study of identification and quantitation of multiresidue pyrethroids in agricultural products by gas chromatography-mass spectrometry

This paper deals with the different GC-MS analytical conditions adopted by four laboratories in an attempt to confirm the accuracy of the GC-electron-capture detection (ECD) analytical results during the international collaborative study for the establishment of the AOAC Official Method 998. 01. What is especially noted is that two laboratories have conducted comparative analysis of the respective 12 blind samples with both methods of GC-ECD and GC-MS, and the analytical results of the two methods turn out to be basically identical. This fully demonstrates that GC-MS is not only an effective confirmation tool in the analysis of the pyrethroid residues but also of sufficient sensitivity regarding the maximum residue limit of determination prescribed by FAO/WHO. Moreover, its selectivity is better than GC-ECD.     

A Method for Quantifying Azoxystrobin Residues in Grapes and Soil Using GC with Electron Capture Detection

A relatively simple method for the determination of azoxystrobin residues in grapes and soil using gas chromatography equipped with electron capture detector (GC-ECD) is described. Samples were extracted with acetone, and further partitioned with dichloromethane and petroleum ether. The extracts were then cleaned up in a glass clean-up column filled with active charcoal and silica gel, and eluted with dichloromethane/ethyl acetate (70:30, v/v). The eluate was collected and concentrated for GC-ECD analysis. The results showed good linearity (r ² = 0.9998) over the concentration range of 6.25–400 ng mL^?1. The limits of detection (LOD) and quantification (LOQ) of azoxystrobin were 3 and 10 ng mL^?1. Recovery from soil and grape samples was in the range of 83.52–107.36 and 82.21–107.31%, with corresponding relative standard deviations (RSD) of 5.21–9.11 and 4.53–5.90% for the three fortified levels. Inter- and intra-day RSDs were in the range of 0.87–6.76 and 2.01–5.46%. The accuracy and sensitivity of the GC-ECD method was independently confirmed by LC and GC-MS. It was demonstrated that the proposed method was simple and efficient, and particularly suitable for detecting azoxystrobin residues in grapes and soil.     

Gas Chromatographic Method for Analysis of p-Synephrine in Citrus aurantium L. Products

A method has been developed and validated for the identification and quantification of p-synephrine in Citrus aurantium L. products. The approach comprises GC-FID analysis followed by GC-MS confirmation after clean-up by solid phase extraction with a strong cation-exchange phase and derivatization with cyclohexanone. Oxazolidine derivative of p-synephrine was subjected to analysis by nuclear magnetic resonance (¹H and ¹³C NMR), GC-FID and GC-MS. The GC method was validated and was found to be linear in the range of 125–500 mg%. Intra-day and inter-day precisions were 3.60 and 3.59%, respectively. Mean recovery from extract of C. aurantium was 78.1 ± 3.64%. The selectivity of the method was further improved by confirmation of oxazolidine derivative of p-synephrine by GC-MS.     

Persistent Organochlorine Insecticide Residues in Some Paddy,Upland and Urban Soils of India

Abstract

A wide variety of agricultural soils from different regions of India such as paddy, wheat, mustard, potato, cotton, tea, tomato, sugarcane, grape and urban soils were surveyed for the residual levels of persistent organochlorine insecticide residues in 1988 and 1989. DDT and HCH concentrations were found to be higher in upland soils and lower in paddy field soils. These results indicate the large application of HCH and DDT compounds for agricultural purposes in India. In urban soil DDT levels were higher than HCHs reflecting the use of the former insecticide in relatively large amounts for vector control. Among DDT compounds, p,p′-DDE showed higher percentage in paddy and upland soils. On the other hand, p,p′-DDT contributed to higher levels in urban soils. The β-HCH was detected as the dominant isomer in both agricultural and non agricultural soils. The levels and percentage compositions of DDTs and HCHs revealed the extent of environmental contamination caused by the continuous usage of persistent organochlorine insecticides in large quantities in tropical areas like India.     

Optimization and validation of organochlorine compounds in adipose tissue by SPE‐gas chromatography

Scientific evidence has shown an association between organochlorine compounds (OCC) exposure and human health hazards. Concerning this, OCC detection in human adipose samples has to be considered a public health priority. This study evaluated the efficacy of various solid‐phase extraction (SPE) and cleanup methods for OCC determination in human adipose tissue. Octadecylsilyl endcapped (C₁₈‐E), benzenesulfonic acid modified silica cation exchanger (SA), poly(styrene‐divinylbenzene (EN) and EN/RP₁₈ SPE sorbents were evaluated. The relative sample cleanup provided by these SPE columns was evaluated using gas chromatography with electron capture detection (GC–ECD). The C₁₈‐E columns with strong homogenization were found to provide the most effective cleanup, removing the greatest amount of interfering substance, and simultaneously ensuring good analyte recoveries higher than 70%. Recoveries > 70% with standard deviations (SD) < 15% were obtained for all compounds under the selected conditions. Method detection limits were in the 0.003–0.009 mg/kg range. The positive samples were confirmed by gas chromatography coupled with tandem mass spectrometry (GC‐MS/MS). The highest percentage found of the OCC in real samples corresponded to HCB, o,p′‐DDT and methoxychlor, which were detected in 80 and 95% of samples analyzed respectively. Copyright © 2012 John Wiley & Sons, Ltd.     

Development of a heterogeneous chemiluminescent flow immunoassay for DDT and related compounds

A heterogeneous chemiluminescent (CL) flow immunoassay for DDT was optimized comparing different types of immunoaffinity supports: beads, nylon coils and membranes (membranes HyBondN+). In order to characterize solid immunoaffinity supports two basic immunoassay formats were performed, using (1) enzyme-labeled secondary and (2) enzyme-labeled specific monoclonal antibodies (MAbs). In both formats, hapten DDT5 conjugated to ovalbumin immobilized on solid supports according to the appropriate immobilization procedure, enzyme label (horseradish peroxidase, HRP) and luminescent detection (luminol/H₂O₂/p-iodophenol) were used. The lowest limit of detection (LOD), 1 nM p,p-DDT, was obtained with a membrane-based flow immunoassay with HRP-labeled specific antibody. Beads and packed tubing were discarded as appropriate supports because of the difficulties encountered for reproducible packing and the occurrence of light scatterring (beads), which seriously compromised the performance and reproducibility of the flow immunoassay.     

Headspace Solid Phase Microextraction for Terpenes and Volatile Compounds Determination in Mastic Gum Extracts,Mastic Oil and Human Urine by GC– MS

A reliable analytical method was developed, which is based on Headspace Solid Phase Microextraction (HS-SPME) and Gas Chromatography–Mass Spectrometry (GC-MS) for the detection of volatile components of the gum and the essential oil of Pistacia lentiscus var. chia, commonly known as mastic gum and mastic oil respectively. The conditions of the HS-SPME were optimized and aqueous-ethanolic extracts of mastic gum and solutions of mastic oil in ethanol-water were analyzed by GC-MS. Almost 26 volatile components in mastic gum and 34 in mastic oil were identified in the gum and the oil respectively. The major constituents of the mastic gum and the mastic oil were α-pinene (63% and 76%, respectively), β-myrcene (15% and 14%), β-pinene (4% and 4%), limonene (2.5% and 1.5%), and caryophyllene (5% and 1%). The quantitative determination of six of the aforementioned substances in multi-analyte standard solutions was achieved with good performance features. The repeatability (RSD%) was <4.2% and the limits of detection were 1.2 µg/L for α-pinene, 0.09 µg/L for β-pinene, 0.7 µg/L for β-myrcene, 0.02 µg/L for camphene, 0.02 µg/L for p-cymene, and 0.07 µg/L for α-terpineol. The HS-SPME/GC-MS procedure was successfully applied to samples of human urine samples after dietetic use of various mastic products such as mastic gum, mastic oil and Greek traditional highly viscous white mastic sweet. Traces of several constituents of mastic, such as α-pinene, β-myrcene, limonene, p-methyl anisole, terpinene, carveol, myrtenol, caryophyllene, α-caryophyllene, and so forth, were detected in the collected urine samples.