Analytical strategy to assess the microbial degradation of poly(butylene-adipate-co-terephthalate)/poly(lactic acid) films.

Plastic is widely used in agricultural applications, but its waste has an adverse environmental impact and a long-term detrimental effect. The development of biodegradable plastics for agricultural use is increasing to mitigate plastic waste. The most commonly used biodegradable plastic is poly(butylene adipate co-terephthalate)/poly(lactic acid) (PBAT/PLA) polymer. In this study, an analytical procedure based on dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography-mass spectrometry (GC-MS) in combination with chemometrics has been optimized to assess the degradation level of PBAT/PLA films by monitoring their characteristic degradation products. Carboxylic acids (benzoic, phthalic, adipic, heptanoic, and octadecanoic acids) and 1,4-butanediol have been found to be potential markers of PBAT/PLA degradation. The DLLME-GC-MS analytical approach has been applied for the first time to assess the degradation efficiency of several microorganisms used as degradation accelerators of PBAT/PLA based on the assigned potential markers. This analytical strategy has shown higher sensitivity and precision than standard techniques, such as elemental analysis, allowing us to detect low degradation levels.

Magnetic Molecularly Imprinted Polymers for Selective Extraction of Aflatoxins from Feeds.

Magnetic molecularly imprinted polymers (MMIPs) have fused molecular imprinting technology with magnetic separation technology, emerging as an innovative material capable of recognizing specific molecules and efficiently separating target substances. Their application to the extraction and purification of mycotoxins has great potential, due to the toxicity and economic impact of these contaminants. In this work, MMIP has been proposed as a sample treatment for the determination of main four aflatoxins (B1, B2, G1 and G2) in pig feed. The MMIP was formed through the integration of magnetic material (Fe3O4) with commercial molecularly imprinted polymers, avoiding the synthesis step and, therefore, simplifying the process. The analyses were carried out by high-performance liquid chromatography with fluorescence detection and the method was validated and limits of quantification (LOQs) between 0.09 and 0.47 ng/g were obtained, below the allowed or recommended levels by the European Union. Repeatability and intermediate precision showed relative standard deviations lower than 10% in all cases and trueness ranged from 92 to 111%. Finally, the proposed method was applied to 31 real pig feed samples, detecting aflatoxins with concentrations between 0.2 and 3.2 ng/g.

Evaluation of distribution of emerging mycotoxins in human tissues: applications of dispersive liquid-liquid microextraction and liquid chromatography-mass spectrometry.

In this work, a complete study of the distribution of emerging mycotoxins in the human body has been carried out. Specifically, the presence of enniatins (A, A1, B, B1) and beauvericin has been monitored in brain, lung, kidney, fat, liver, and heart samples. A unique methodology based on solid-liquid extraction (SLE) followed by dispersive liquid-liquid microextraction (DLLME) was proposed for the six different matrices. Mycotoxin isolation was performed by adding ultrapure water, acetonitrile, and sodium chloride to the tissue sample for SLE, while the DLLME step was performed using chloroform as extraction solvent. Subsequently, the analysis was carried out by high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). The proposed method allowed limits of quantification (LOQs) to be obtained in a range of 0.001-0.150 ng g-1, depending on the tissue and mycotoxin. The precision was investigated intraday and interday, not exceeding of 9.8% of relative standard deviation. In addition, trueness studies achieved 75 to 115% at a mycotoxin concentration of 25 ng g-1 and from 82 to 118% at 5 ng g-1. The application of this methodology to 26 forensic autopsies demonstrated the bioaccumulation of emerging mycotoxins in the human body since all mycotoxins were detected in tissues. Enniatin B (ENNB) showed a high occurrence, being detected in 100% of liver (7 ± 13 ng g-1) and fat samples (0.2 ± 0.8 ng g-1). The lung had a high incidence of all emerging mycotoxins at low concentrations, while ENNB, ENNB1, and ENNA1 were not quantifiable in heart samples. Co-occurrence of mycotoxins was also investigated, and statistical tests were applied to evaluate the distribution of these mycotoxins in the human body.

Determination of extractable pollutants from microplastics to vegetables: Accumulation and incorporation into the food chain.

The presence and impacts of microplastics (MPs) are being extensively researched and reviewed, especially in the marine environment. However, mobility, transportation routes, and accumulation of leaching compounds such as additives in plastic waste including MPs are scarcely studied. Information regarding ecotoxicity and leachability of compounds related to MPs contamination in the environment is limited. Current work presents the levels of leachates from plastic materials in edible-root and non-edible root vegetables. Samples were analyzed by static headspace and gas chromatography-mass spectrometry (SHS-GC-MS) and the presence of 93 putative compounds was accurately monitored in the samples by the usage of Mass Spectrometry-Data Independent Analysis software. The application of chemometrics to the SHS-GC-MS dataset allowed differentiation between the levels of plastic related compounds in edible root and non-edible root vegetables, the former showing a higher content of plastic leachates. For SHS sampling, 3 g of the sample were incubated at 130 °C for 35 min in the HS vial and toluene and naphthalene were added as internal standards for quantification purposes. The developed SHS-GC-MS methodology is straightforward, reliable, and robust and allowed the quantification of sixteen plastic associated compounds in the samples studied in a range from 0.14 to 28800 ng g-1 corresponding to 2,4-di-tert-butylphenol and p,α-dimethylstyrene, respectively. Several of the quantified compounds pointed out to potential contamination of polystyrene and/or polyvinyl chloride MPs.

Monitoring of hydroxylated polycyclic aromatic hydrocarbons in human tissues: Targeted and untargeted approaches using liquid chromatography-high resolution mass spectrometry.

Hydroxylated polycyclic aromatic hydrocarbons are metabolites of persistent organic pollutants which are formed during the bioactivation process of biological matrices and whose toxicity is being studied. The aim of this work was the development of a novel analytical method for the determination of these metabolites in human tissues, known to have bioaccumulated their parent compounds. Samples were treated by salting-out assisted liquid-liquid extraction and the extracts were analyzed by ultra-high performance liquid chromatography coupled to mass spectrometry with a hybrid quadrupole-time-of-flight analyzer. The proposed method achieved limits of detection in the 0.15-9.0 ng/g range for the five target analytes (1-hydroxynaphthalene, 1-hydroxypyrene, 2-hydroxynaphthalene, 7-hydroxybenzo[a]pyrene, and 9-hydroxyphenanthrene). The quantification was achieved by matrix-matched calibration using 2,2´-biphenol as internal standard. For all compounds, relative standard deviation, calculated for six successive analyses, was below 12.1%, demonstrating good precision for the developed method. None of the target compounds was detected in the 34 studied samples. Moreover, an untargeted approach was applied to study the presence of other metabolites in the samples, as well as their conjugated forms and related compounds. For this objective, a homemade mass spectrometry database covering 81 compounds was created and none of them was detected in the samples.

Headspace with Gas Chromatography-Mass Spectrometry for the Use of Volatile Organic Compound Profile in Botanical Origin Authentication of Honey.

The botanical origin of honey determines its composition and hence properties and product quality. As a highly valued food product worldwide, assurance of the authenticity of honey is required to prevent potential fraud. In this work, the characterisation of Spanish honeys from 11 different botanical origins was carried out by headspace gas chromatography coupled with mass spectrometry (HS-GC-MS). A total of 27 volatile compounds were monitored, including aldehydes, alcohols, ketones, carboxylic acids, esters and monoterpenes. Samples were grouped into five categories of botanical origins: rosemary, orange blossom, albaida, thousand flower and "others" (the remaining origins studied, due to the limitation of samples available). Method validation was performed based on linearity and limits of detection and quantification, allowing the quantification of 21 compounds in the different honeys studied. Furthermore, an orthogonal partial least squares-discriminant analysis (OPLS-DA) chemometric model allowed the classification of honey into the five established categories, achieving a 100% and 91.67% classification and validation success rate, respectively. The application of the proposed methodology was tested by analysing 16 honey samples of unknown floral origin, classifying 4 as orange blossom, 4 as thousand flower and 8 as belonging to other botanical origins.

Application of untargeted volatile profiling in inflammatory bowel disease research.

Inflammatory bowel disease (IBD) diagnosis depends on criteria based on histological, endoscopic, radiological, and clinical results. These studies show drawbacks as being expensive, invasive, and time-consuming. In this work, an untargeted metabolomic strategy based on the monitoring of volatile compounds in serum by headspace gas chromatography-mass spectrometry is proposed as a complementary, fast, and efficient test for IBD patient diagnosis. To develop the method and build a chemometric model that allows the IBD diagnosis, serum samples including IBD patients and healthy volunteers were collected. Analyses were performed by incubating 400 µL of serum for 10 min at 90 °C. For data processing, an untargeted metabolomic strategy was used. A total of 96 features were detected, of which a total of 10 volatile compounds could be identified and confirmed by means of the analysis of real standards. The chemometric treatment consisted of a discriminant analysis of orthogonal partial least squares (OPLS-DA) obtaining a 100% of classification rate, since all the analyzed samples were correctly classified.

Use of polypyrrole ferrite microparticles and liquid chromatography-mass spectrometry for testing natural grass contamination by multiclass mycotoxins.

An analytical methodology based on the combination of dispersive magnetic solid-phase extraction (DMSPE) and liquid chromatography-mass spectrometry (LC-MS) is proposed to explore the occurrence of 13 mycotoxins (aflatoxins B1, G1, B2, and G2; deoxynivalenol; T-2 toxin; ochratoxin A; HT-2 toxin; enniatins A, A1, B, and B2; and beauvericin) and their derivatives in natural grass samples. Magnetic microparticles (Fe3O4) coated with polypyrrole (PPy) polymer were used in DMSPE sample treatment as adsorbent phase, and Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, and energy dispersive X-ray spectroscopy have been used for its characterization. The experimental parameters influencing the adsorption and desorption steps of DMSPE have been optimized. Method validation has been carried out obtaining limits of quantification between 0.07 and 92 µg kg-1 corresponding to enniatin B or A1 and DON, respectively. A total of 83 natural grass samples from 8 dehesa farms were analysed. Enniatin B was found in all the samples (0.29 to 488 µg kg-1 concentration range) followed by enniatin B1 (92.8% of the samples) with a 0.12-137 µg kg-1 concentration range. Moreover, co-occurrence of mycotoxins was studied and between 2 and 5 mycotoxins appeared simultaneously in 97.6% of the samples. Distribution of the contamination according to natural grass location was also investigated.

Analytical Platform for the Study of Metabolic Pathway of Propyl Propane Thiosulfonate (PTSO) from Allium spp.

The present work is focused on the development of an analytical platform to elucidate the metabolic pathway of PTSO from onion, an organosulfur compound well-known for its functional and technological properties and its potential application in animal and human nutrition. This analytical platform consisted of the use of gas chromatography-mass spectrometry (GC-MS) and ultra-high performance liquid chromatography quadrupole with time-of-flight MS (UHPLC-Q-TOF-MS) in order to monitor volatile and non-volatile compounds derived from the PTSO. For the extraction of the compounds of interest, two different sample treatments were developed: liquid-liquid extraction (LLE) and salting-out assisted liquid-liquid extraction (SALLE) for GC-MS and UHPLC-Q-TOF-MS analysis, respectively. Once the analytical platform was optimised and validated, an in vivo study was planned to elucidate PTSO metabolisation, revealing the presence of dipropyl disulfide (DPDS) in liver samples with concentrations between 0.11 and 0.61 µg g-1. The DPDS maximum concentration in the liver was observed at 0.5 h after the intake. DPDS was also present in all plasma samples with concentrations between 2.1 and 2.4 µg mL-1. In regard to PTSO, it was only found in plasma at times above 5 h (0.18 µg mL-1). Both PTSO and DPDS were excreted via urine 24 h after ingestion.

Dispersive magnetic solid-phase extraction for capsaicinoid compounds in human serum using LC-HRMS: targeted and non-targeted approaches.

A new analytical method based on the use of dispersive magnetic solid-phase extraction (DMSPE) is described for the preconcentration of capsaicin (CAP), dihydrocapsaicin (DCAP), and N-vanillylnonanamide (PCAP) from human serum samples. The influence of several experimental factors affecting the adsorption (nature and amount of magnetic material, adsorption time, and pH) and desorption (nature of solvent, its volume and desorption time) steps was studied. Among seven different nanomaterials studied, the best results were obtained using magnetic multiwalled carbon nanotubes, which were characterized by means of spectrometry- and microscopy-based techniques. Analyses were performed by ultra-high-performance liquid chromatography with quadrupole-time-of-flight mass spectrometry using electrospray ionization in positive mode (UHPLC-ESI-Q-TOF-MS). The developed method was validated by obtaining several parameters, including linearity (0.3-300 µg L-1 range), and limits of detection which were 0.1, 0.15, and 0.17 µg L-1 for CAP, DCAP, and PCAP, respectively. The repeatability of the method, expressed as relative standard deviation (RSD, n = 7), varied from 3.4 to 11%. The serum samples were also studied through a non-targeted approach in a search for capsaicinoid metabolites and related compounds. With this objective, the fragmentation pathway of this family of compounds was initially studied and a strategy was established for the identification of novel or less studied capsaicinoid-derived compounds.

Reddish Colour in Cooked Ham Is Developed by a Mixture of Protoporphyrins Including Zn-Protoporphyrin and Protoporphyrin IX.

The nitrosyl-heme complex is considered the pigment responsible for the development of reddish colour in cooked hams. However, the same reddish colour was observed in a nitrite-free product elaborated with polyphenols, suggesting the presence of other red pigments that can contribute to generate this colour. In this study, the protoporphyrins composition of the pigment solution obtained from nitrite and nitrite-free cooked hams was analysed using 80% (v/v) acetone/water solution for extraction. Chromatographic analysis using a combination of diode array and fluorescence detectors revealed the presence of protoporphyrin IX and Zn-protoporphyrin IX in this solution, and these protoporphyrins were subsequently identified with complete certainty by mass spectrometry. These results show how the colour of cooked hams can be developed by a mixture of different protoporphyrins and also demonstrate the absence of selectivity of acetone/water extraction for measuring the content of nitrosyl-heme in cooked hams.

A non-targeted metabolomic strategy for characterization of the botanical origin of honey samples using headspace gas chromatography-ion mobility spectrometry.

In this work, characterization of the botanical origin of honey was carried out using headspace gas chromatography coupled to ion mobility spectrometry (HS-GC-IMS). The proposed methodology was applied for the analysis of 89 samples from ten different botanical origins. A total of 15 volatile compounds could be identified, namely, 3-methyl-1-butanol, heptanal, valeraldehyde, octanal, trans-2-hexenal, nonanal, hexanal, benzaldehyde, 2-heptanone, 2-butanone, 2-hexanone, 6-methyl-5-hepten-2-one, 2-pentanone, ethyl acetate and linalool. The analytical method was characterized in terms of limits of detection and quantification, and precision, in order to quantify the identified compounds. Compounds were quantified using the sum of the protonated monomer and proton-bound dimer and logarithmic regression (R2 > 0.98), although the establishment of a concentration threshold that would allow creation of classification rules was not possible since there was variability within the group. Consequently, the establishment of chemometric models was necessary. A non-targeted strategy using 275 features is proposed. Orthogonal partial least squares-discriminant analysis (OPLS-DA) allowed the differentiation of five botanical origins: thousand flowers, rosemary, albaida, orange blossom, and "others" (rest of the investigated botanical origins, since a limited number of samples was available). A success validation rate of 100% allowed the classification of 14 honeys with unknown botanical origin.

Free and glycosylated aroma compounds in grapes monitored by solid-liquid extraction and dispersive liquid-liquid microextraction combined with gas chromatography-mass spectrometry.

Fifteen aroma compounds have been determined in their free and glycosylated forms in grapes using dispersive liquid-liquid microextraction with gas chromatography-mass spectrometry. The sample treatment includes a previous solid-liquid extraction stage and subsequent parallel microextraction approaches to preconcentrate total aroma content and the free fraction. Thus, the extraction of the total content of analytes requires previous enzymatic hydrolysis of the bound forms. For preconcentration, chloroform (250 µl) and acetonitrile (1.5 ml) were added to 10 ml of the sample extract in the presence of 0.5 g sodium chloride. The absence of matrix effect in the samples allowed quantification against aqueous external standards. Limits of detection ranged between 5 and 30 ng/g, depending on the compound. Method accuracy was studied through recovery assays, with recoveries in the 82-115% range being obtained. Relative standard deviations for repeatability studies were lower than 12%. Four different samples of grapes were analyzed, being quantified linalool in its free form at concentrations in the 359-470 ng/g range, and benzyl alcohol, 2-phenylethanol, and linalool oxide I and II in their bound forms between 52 and 464 ng/g.

Authentication of recycled plastic content in water bottles using volatile fingerprint and chemometrics.

The environment is threatened by the continuously increasing volume of plastic residue. Plastic recycling is an interesting alternative to mitigate this problem. However, recycled plastic products may have pollutants from their recycling process, collecting system and/or previous life which may hurt consumers health, thus making it key to authenticate and characterize recycled materials. An innovative non-targeted methodology by means of static headspace gas chromatography-mass spectrometry (SHS-GC-MS) has been developed to measure the volatile organic profile of virgin polyethylene terephthalate (PET) and with diverse content of recycled PET samples. A home-made MS database, with 161 organic compounds characteristics from plastic materials based on the literature, was made. Seventeen of those compounds were found in the studied samples and identified by matching their MS spectra with MS database libraries. These compounds are mainly aldehydes (pentanal, hexanal, heptanal, octanal, nonanal and decanal), and benzene derivatives (styrene, p-xylene, benzaldehyde, methylbenzene, and 1,2-dichlorobenzene) which we found to be the common in the samples of recycled PET. The combination of the dataset consisting in the peak area of the detected species by SHS-GC-MS and the use of chemometrics shown to be a valuable methodology for the discrimination between virgin PET samples and those with different recycled PET content based on their volatile profile. In addition, a novel strategy applying a statistical model based on partial least squares (PLS) regression was proposed, for the first time, to quantify the recycled plastic content in the PET samples.

Non-targeted analysis by DLLME-GC-MS for the monitoring of pollutants in the Mar Menor lagoon.

Non-targeted analysis for the monitoring of organic pollutants resulting from agricultural and industrial practices, plastics and pharmaceutical products of seawater from the Mar Menor lagoon (SE Spain) is proposed using dispersive liquid-liquid microextraction (DLLME) and gas chromatography-mass spectrometry (GC-MS). Initially, a home-made MS database including 118 environmental organic pollutants, whose presence in different ecosystems has already been reported, was created. The analytical method was applied for the analysis of 42 samples and a total of 18 pollutants were detected and identified. Samples were obtained from different sites around the Mar Menor in three sampling campaigns, enabling the assessment of impact of rain on the input of the detected chemicals and their distribution. In addition, this methodology was validated using a standard mixture containing 54 of the environmental pollutants included in the database, allowing the quantification of the 9 of the identified compounds (dibutyl phthalate, diisobutyl phthalate, diethyl phthalate, bis(2-ethylhexyl) phthalate, anthracene, 2-methylnaphthalene, hexachlorocyclopentadiene, bis(2-ethylhexyl) adipate and oleamide) with concentration between 3 and 271 µg L-1.

Ultrasound Assisted Extraction Approach to Test the Effect of Elastic Rubber Nettings on the N-Nitrosamines Content of Ham Meat Samples.

Nitrosamines (NAs), which are catalogued as carcinogenic compounds, may be present in meat products due to the conversion of nitrites and as result of migration from elastic rubber nettings used. A method based on ultrasonic assisted extraction coupled with dispersive liquid-liquid microextraction as sample treatment and gas chromatography-mass spectrometry as separation and detection technique was proposed for the determination of twelve NAs in cooked ham samples. The method was validated by evaluating linearity (0.5-1000 ng g-1), matrix effect, sensitivity (detection limits were between 0.15 and 1.4 ng g-1) and precision, which was below 12%. Five NAs were found in the samples with levels ranging from not quantifiable to 40 ng g-1. The effect of the elastic rubber nettings on the nitrosamine content of meat was evaluated by comparing the levels found in products made with several plastics or thread in the presence of additives.

Cellulose-ferrite nanocomposite for monitoring enniatins and beauvericins in paprika by liquid chromatography and high-resolution mass spectrometry.

Paprika is considered a high-quality product being one of the most consumed spices in the world. Contamination with mycotoxins may appear due to inappropriate practices during processing or resulting from invading mould in the final manufactured products. A sample treatment based on dispersive magnetic solid-phase extraction (DMSPE) has been proposed for emerging mycotoxin determination, enniatins (ENNs) and beauvericins (BEAs), in paprika. Different magnetic nanoparticles were tested, and cellulose-ferrite nanocomposite was selected for the extraction and preconcentration of the mycotoxins. Nanocomposite was characterised using field emission scanning electron microscopy and energy dispersive X-ray spectroscopy in terms of morphology and elemental composition. High-resolution mass spectrometry allowed the quantification of the five main emerging mycotoxins and the monitoring of unexpected members of this class of toxic fungal secondary metabolites. The method has been validated, obtaining limits of quantification between 9.5 and 9.9 µg kg-1 and testing its trueness through recovery studies, with satisfactory values of between 89.5 and 97.7%. Relative standard deviations were calculated to evaluate the intra- and inter-day precision and values lower than 8% were obtained in all cases. The analysis of 26 samples, including conventional and organic, demonstrated the presence of ENNB1 at 12.0 ± 0.6 µg kg-1 in one of the samples studied. Other analogues ENNs and BEAs were not detected.

Monitoring Lipophilic Toxins in Seawater Using Dispersive Liquid-Liquid Microextraction and Liquid Chromatography with Triple Quadrupole Mass Spectrometry.

The use of dispersive liquid-liquid microextraction (DLLME) is proposed for the preconcentration of thirteen lipophilic marine toxins in seawater samples. For this purpose, 0.5 mL of methanol and 440 µL of chloroform were injected into 12 mL of sample. The enriched organic phase, once evaporated and reconstituted in methanol, was analyzed by reversed-phase liquid chromatography with triple-quadrupole tandem mass spectrometry. A central composite design multivariate method was used to optimize the interrelated parameters affecting DLLME efficiency. The absence of any matrix effect in the samples allowed them to be quantified against aqueous standards. The optimized procedure was validated by recovery studies, which provided values in the 82-123% range. The detection limits varied between 0.2 and 5.7 ng L-1, depending on the analyte, and the intraday precision values were in the 0.1-7.5% range in terms of relative standard deviation. Ten water samples taken from different points of the Mar Menor lagoon were analyzed and were found to be free of the studied toxins.

Targeted and untargeted gas chromatography-mass spectrometry analysis of honey samples for determination of migrants from plastic packages.

Plastic food packages usually contain additives which may migrate from the package into the food and then be ingested by the consumer, representing a risk for their health. In this study, targeted and untargeted analysis by gas chromatography-mass spectrometry (GC-MS) is proposed to monitor any contaminants of this type in honey. The application of dispersive liquid-liquid microextraction (DLLME) as a preconcentration technique allowed very low detection limits to be reached for all the substances. Fifteen target compounds, including styrene, phthalates, fatty acids, alkylphenols and bisphenol A, were quantified. Untargeted analyses were also carried out, allowing other migrants in the honey samples to be identified, such as two phthalates, four acids, three esters, one aldehyde, one hydrocarbon and two alkyl phenol compounds. The proposed method was seen to be a useful approach for the quantification and identification of potential migrants from plastics in challenging samples such as honey.

Occurrence of Organochlorine Pesticides in Human Tissues Assessed Using a Microextraction Procedure and Gas Chromatography-Mass Spectrometry.

This work focuses on the development, validation and application of an analytical method for the determination of twenty organochlorine pesticides (OCPs) in human tissues using salting-out liquid-liquid extraction and dispersive liquid-liquid microextraction for sample preparation and gas chromatography-mass spectrometry to analyze the obtained extracts. Measurement of the concentration levels of these toxics in tissues can be used to assess the risk of the population to exposure. The linearity of the proposed method was verified in the 10-1,000 ng/g range. The sensitivity was evaluated calculating the limits of detection (LODs) for 20 OCPs (α-, ß-, γ- and δ-hexachlorocyclohexane (HCH), α- and ß-endosulfan, endosulfan sulfate, aldrin, dieldrin, endrin, endrin ketone, endrin aldehyde, α- and γ-chlordane, 4,4'-dichlorodiphenyltrichloroethane, 4,4'-dichlorodiphenyldichloroethylene (DDE), 4,4'-dichlorodiphenyldichloroethane, heptachlor, heptachlor epoxide and methoxychlor), most of them being found between 1.0 and 16 ng/g. The intra- and interday precisions were <12% for relative standard deviation values. The accuracy of the method was evaluated by recovery studies, which gave recovery percentages in the 85-109% range. Seven different tissues (liver, kidney, heart, spleen, lung, brain and abdominal fat) from eight autopsies were analyzed, and only three cases were seen to have ß-HCH and 4,4'-DDE in abdominal fat, while 4,4'-DDE was also detected in the heart of one case. The rest of the samples were free of the studied OCPs at least above the corresponding LODs.