Disposition of [14C]-polystyrene microplastics after oral administration to lactating sheep.

Microplastics have become a ubiquitous contaminant, but their fate in food animals is largely unknown. In this study, [14C]-polystyrene microplastic (PS-MP) particles were orally dosed to lactating sheep to evaluate their absorption and disposition. Elimination of the [14C]-PS-MP was predominately through faeces with faecal radioactivity peaking at 24 h post-dosing but continuing to be present throughout the entire 72 h study period. Only a small fraction (≤ 1%) of the dosed [14C]-PS-MP was present in blood, milk, and urine. Pharmacokinetic analysis of blood plasma radioactivity, using non-compartment modeling, indicated rapid absorption (T1/2 0.4 to 3 h) with slow elimination (T1/2 37 to 48 h). Radioactivity in milk and urine had similar elimination patterns with radiocarbon activities peaking 24 h post-dosing with detectable elimination throughout the 72 h study period. No radioactivity was quantifiable in tissues at the 72 h withdrawal period.

Comparison of immunoassay and LC-tandem mass spectrometry analyses of ractopamine in hog oral fluid.

The accurate detection of ractopamine in food animals is crucial for marketing since some entities require animals or animal carcasses to be free of ractopamine residues. Field-based ractopamine screening tests that are rapid, sensitive, and capable of high-throughput are highly desirable to ensure that inadvertent exposure to ractopamine did not occur in animals marketed as animals that have not been fed ractopamine. An immunochemically based lateral flow assay was used to analyze oral fluids from hogs never exposed to ractopamine and from hogs that were presumed positives and results were confirmed using an enhanced sensitivity LC-MSMS method. We found that an immunochemically based lateral flow system having a working range of 2.5 to 15 ng mL-1 worked well as a screening assay with 1.7% false positive results in freshly collected hog oral fluids. Using ractopamine glucuronide standards and LC-MSMS, we determined that the false positive results were not due to the presence of ractopamine glucuronide metabolites in oral fluids.

Effects of polystyrene micro/nanoplastics on liver cells based on particle size, surface functionalization, concentration and exposure period.

Micro/nanoplastics (MP/NP) contaminate our food and drinking water but their impact on human health has not been well-documented. The liver is one of the first organs that ingested MP/NP encounter and it has a major role in the clearance of xenobiotics. Therefore, the effects of polystyrene MP/NP on liver HepG2 cells were studied. Cellular responses to particles of various sizes (50-5000 nm) and surface functionalization (aminated, carboxylated or non-functionalized) were determined at different concentrations (0.1-100 µg/mL) and exposure periods (1-24 h). Smaller sized particles were internalized by HepG2 cells more avidly than larger particles regardless of functionalization; the highest uptake being for 50 and 100 nm aminated particles at lower concentrations. Confocal microscopy images of cells corroborated quantitative uptake results. Aminated particles were more toxic to the cells than carboxylated or non-functionalized particles. Among aminated particles smaller particles (50 and 100 nm) were more detrimental to cell viability compared to larger particles (1000 or 5000 nm) with toxicity increasing with concentration. Treatment with the particles for 4 h increased intracellular concentrations of Caspase-3 by 1.5-2.8 fold, but 24 h exposure to the particles attenuated this increase in Caspase-3 concentrations. A slight trend of higher Caspase-3 concentration in cells treated with larger particles (500-5000 nm) compared to smaller particles (50-200 nm) was observed, indicating that larger particles are more likely to direct cells toward apoptotic cell death upon 4 h exposure. Exposure of cells to large PS particles (500-5000 nm) upregulated interleukin-8 and the effect was enhanced at 24 h. Overall, the study demonstrated that smaller aminated particles were most toxic to hepatocytes, but larger particles induced apoptotic cell death or an inflammatory response depending on the length of exposure.

Urinary Concentrations of Triclosan, Bisphenol A, and Brominated Flame Retardants and the Association of Triclosan with Demographic Characteristics and Body Fatness among Women with Newly Diagnosed Breast Cancer.

Background: Triclosan, bisphenol A (BPA), and brominated flame retardants are environmental estrogenic endocrine-disrupting compounds that may influence the prognosis of breast cancer. We examined the urinary concentrations of these compounds and their associations with demographic characteristics and body fatness in a population of women with newly diagnosed breast cancer. Methods: Overnight urine collection and anthropometric measures were obtained from 302 participants. Triclosan, BPA, tetrabromobisphenol A (TBBPA), and tetrabromobenzoic acid (TBBA) concentrations were determined using ultra-performance liquid chromatography−tandem mass spectrometry. Regression analyses were conducted to examine associations of urinary compound concentration with age, menopause, race, ethnicity, educational level, estrogen receptor status, body size, and body composition. Results: Triclosan, BPA, and TBBA were detected in urine samples from 98.3%, 6.0%, and 0.3% of patients, respectively; TBBPA was undetectable. Among patients with quantifiable values, the geometric mean concentrations were 20.74 µg/L (27.04 µg/g creatinine) for triclosan and 0.82 µg/L (1.08 µg/g creatinine) for BPA. Body mass index ≥ 30 vs. <25 kg/m2 was associated with lower creatinine-corrected urinary concentrations of triclosan (−40.00, 95% confidence interval [CI] = −77.19 to −2.81; p = 0.0351). The observed association was predominantly in postmenopausal women (−66.57; 95% CI: −109.18% to −23.96%). Consistent results were found for associations between triclosan levels and fat mass variables. Conclusion: In this study population, women with newly diagnosed breast cancer had triclosan exposure. Assessments of the implications of urinary concentrations of triclosan for women should consider body fatness and menopausal status.

Evaluation of rapid and standard tandem mass spectrometric methods to analyse veterinary drugs and their metabolites in antemortem bodily fluids from food animals.

Antemortem bodily fluids can serve as an indicator of veterinary medicine exposure prior to food animal slaughter. A multi-residue, rapid screen electrospray ionisation mass spectrometric (RS-ESI-MS) method was developed to analyse 10 veterinary drugs or metabolites (clenbuterol, erythromycin, flunixin, 5-hydroxyflunixin, meloxicam, ractopamine, ractopamine-glucuronide, salbutamol, tylosin, and zilpaterol) in hog oral fluid and bovine urine. Simple acetonitrile extraction with salting-out was employed to remove the analytes from matrices in less than 30 minutes. Instrumental analysis time was < 1 min/injection. Regression coefficients of matrix-matched calibration curves ranged 0.9743-0.9999 across all compounds with limits of detection ranging from 0.46-108 ng mL-1 for cattle urine and 0.19-64.4 ng mL-1 for hog oral fluid across all analytes. Except for ractopamine-glucuronide, analyte recoveries ranged from 92.7-106% for oral fluid and urine fortified at 30, 100, and 300 ng mL-1, with inter-day variations of < 25%. Ractopamine-glucuronide recovery was 93.3% for oral fluid fortified at 300 ng mL-1. The RS-ESI-MS method accurately identified ractopamine and/or ractopamine-glucuronide in incurred cattle urine with results correlating well with traditional LC-MS/MS and HPLC fluorescence methods. As far as we are aware, this is the first report of the direct quantification of ractopamine-glucuronide from biological matrices without lengthy hydrolysis and cleanup steps.

Uptake and toxicity of polystyrene micro/nanoplastics in gastric cells: Effects of particle size and surface functionalization.

Toxicity of micro or nanoplastics (MP/NP) in aquatic life is well-documented, however, information about the consequences of exposure to these particles in terrestrial species is scarce. This study was used to evaluate the uptake and/or toxicity of polystyrene MP/NP in human gastric cells, comparing doses, particle sizes (50, 100, 200, 500, 1000 or 5000 nm) and surface functionalization (aminated, carboxylated or non-functionalized). In general, the uptake of 50 nm particles was significantly higher than 1000 nm particles. Among the 50 nm particles, the aminated particles were more avidly taken up by the cells and were cytotoxic at a lower concentration (≥ 7.5 µg/mL) compared to same sized carboxylated or non-functionalized particles (≥ 50 µg/mL). High toxicity of 50 nm aminated particles corresponded well with significantly high rates of apoptosis-necrosis induced by these particles in 4 h (29.2% of total cells) compared to all other particles (≤ 16.8%). The trend of apoptosis-necrosis induction by aminated particles in 4 h was 50 > 5000 > 1000 > 500 > 200 > 100 nm. The 50 nm carboxylated or non-functionalized particles also induced higher levels of apoptosis-necrosis in the cells compared to 100, 1000 and 5000 nm particles with same surface functionalization but longer exposure (24 h) to 50 nm carboxylated or non-functionalized particles significantly (p<0.0001) increased apoptosis-necrosis in the cells. The study demonstrated that the toxicity of MP/NP to gastric cells was dependent on particle size, dose surface functionalization and exposure period.

Micro- and Nanoplastic-Mediated Pathophysiological Changes in Rodents, Rabbits, and Chickens: A Review.

ABSTRACT: Plastics provide tremendous societal benefits and are an indispensable part of our lives. However, fragmented plastics or those intentionally manufactured in small sizes (microplastics and nanoplastics) are of concern because they can infiltrate soils and enter the human food chain through trophic transfer. The pathophysiological impacts of micro- and nanoplastics in humans are not characterized, but their effects in terrestrial mammals may help elucidate their potential effects in humans. Rodent studies have demonstrated that micro- and nanoplastics can breach the intestinal barrier, accumulate in various organs, cause gut dysbosis, decrease mucus secretion, induce metabolic alterations, and cause neurotoxicity, among other pathophysiologic effects. Larger mammals such as rabbits can also absorb microplastics orally. In farm animals such as chickens, microplastics have been detected in the gut, thereby raising food safety concerns. This review mostly focuses on studies conducted to assess effects of micro- and nanoplastic exposure through food and water in terrestrial mammals and farm animals including rodents, rabbits, and chickens; identifies main knowledge gaps; and provides recommendations for further research to understand foodborne micro- and nanoplastic toxicity in humans.

Performance of allergen testing in a survey of frozen meals and meals ready-to-eat (MREs).

A 7-plex immunoassay capable of detecting cashew, egg, hazelnut, milk, peanut, shrimp, and soy allergens was used to screen meals ready-to-eat (MREs) and frozen meals that contained meat or poultry. The same food matrices were also evaluated using single individual allergen immunoassays. Multiplex and single allergen test results were compared with the allergen declared on the food label, which was considered the standard. For both the frozen meals (n = 113) and MREs (n = 24) each analytical method failed to detect allergens that were declared on product labels, but only in frozen meals were allergens detected that were not declared on the label. Undeclared allergens were detected for egg in 1.8% (2/113) and for soy in 7.1% (8/113) of frozen meals. Labelled allergens were not detected in 0.9% (1/113) of milk, 4.4% (5/113) of egg, and 15% (17/113) of soy allergens in frozen meals. Assay performance for evaluating allergens in MREs was poor.

Electrospray Ionization Inlet Tandem Mass Spectrometry: A Hyphenated Method for the Sensitive Determination of Chemicals in Animal Tissues and Body Fluids.

This study demonstrates the utility of electrospray ionization inlet mass spectrometry (ESII-MS/MS) for the quantitative determination of analytes in complex animal matrices without chromatographic separation. Veterinary drugs including flunixin, its metabolite 5-hydroxyflunixin, and zilpaterol and persistent organic perfluoroalkyl compounds were determined in incurred plasma, urine, and/or tissue samples. Limits of detection (LOD) of zilpaterol in kidney, liver, lung, and muscle ranged from 0.02 to 0.06 ng/g, whereas the limit of quantitation (LOQ) for zilpaterol in all tissues was 0.1 ng/g. For urinary or plasma flunixin, 5-hydroxyflunixin, and PFOS/PFHxS, LODs ranged from 0.1 to 0.7 ng/mL while the LOQs ranged from 0.4 to 50 ng/mL. Regression coefficients for matrix-matched standard curves were 0.993-0.997, 0.977-0.999, and 0.999 for plasma, tissues, and urine, respectively. Correlations between quantitative results obtained by ESII-MS/MS and LC-MS for flunixin, 5-hydroxyflunixin, and zilpaterol ranged from 0.930 to 0.985. ESII-MS/MS provided rapid, sensitive, and accurate analyses of veterinary drugs and environmental contaminants from complex matrices without chromatographic separation.

Micro- and nanoplastic induced cellular toxicity in mammals: A review.

Plastic based products are ubiquitous due to their tremendous utility in our daily lives. However, the limited biodegradable nature of plastics has recently raised pollution concerns globally, especially micro- and nanoplastics. These anthropogenic pollutants are either manufactured specifically in the small size range for various commercial applications or formed due to fragmentation of macro plastics in the environment. Micro- and nanoplastics are currently widespread in the oceans, freshwater bodies, land and even present in our food. The biological effects of micro- and nanoplastics on aquatic organisms are well documented but their impacts on mammalian system have not been rigorously investigated. This review discusses the potential routes of exposure to micro- and nanoplastics, biological effects of these particles in mammalian cells, factors influencing toxicity, and the probable mechanisms of cytotoxicity. In general, small size, positive charge, high dose, and presence of toxic additives or pollutants in the micro/nanoplastics appear to induce cellular toxicity through oxidative stress, membrane damage, immune response and genotoxicity. Understanding the cellular fate and toxicity of these materials may help extrapolate risks to mammals.

Electrospray ionization rapid screening sans liquid chromatography column: A sensitive method for detection and quantification of chemicals in animal tissues and urine.

RATIONALE: Electrospray ionization mass spectrometry (ESI-MS) in conjunction with liquid chromatography (LC) can provide accurate quantitative data, but it is not well-suited for the rapid screening (RS) of analytes incurred into complex matrices. This study was designed to determine the usefulness of ESI for rapid detection and quantitation of veterinary drugs from complex biological matrices under near real-time conditions. METHODS: Nine veterinary drugs or metabolites, clenbuterol, erythromycin, flunixin, 5-hydroxyflunixin, meloxicam, ractopamine, salbutamol, tylosin and zilpaterol, present in cow urine, sheep urine, sheep tissues (kidney, muscle, liver and lung) or pig kidney, were simultaneously analyzed. A simple sample clean-up procedure, which included dilution with 10% sodium carbonate followed by extraction with ethyl acetate, was used. For tissues, an additional pre-extraction with hexane was performed to remove fat prior to MS analysis. Samples were introduced into the mass spectrometer through the LC autosampler, but no chromatographic separation was employed. A Sciex 5600+ triple time-of-flight mass spectrometer with a dual-spray source interfaced with a Shimadzu Nexera LC system was used. Samples were analyzed in positive ion mode. RESULTS: Sample extraction times were typically 10-30 min or less and instrumental analysis time was 1 min/sample. Regression coefficients of matrix-matched standard curves across all compounds ranged from 0.9701-0.9999 in urine (cow and sheep) and tissues (sheep kidney, liver, lung, muscle and pig kidney). Limits of detection ranged from 0.11 to 2.03 ng/mL across analytes in urine and 0.11 to 8.86 ng/g across tissues. Correlations between RS-ESI-MS and LC/MS/MS results were 0.956 to 0.998 for incurred residues of flunixin in cow urine, ractopamine in pig kidney and zilpaterol in sheep urine. CONCLUSIONS: RS-ESI-MS provided rapid, sensitive, and accurate analyses of nine veterinary drugs from complex matrices with very little sample preparation and produced quantitative data akin to LC/MS/MS.

Pharmacokinetic Parameters and Estimated Milk Withdrawal Intervals for Domestic Goats (Capra Aegagrus Hircus) After Administration of Single and Multiple Intravenous and Subcutaneous Doses of Flunixin Meglumine.

Introduction: The study objectives were to estimate plasma flunixin (FLU) pharmacokinetic parameters and milk depletion profiles for FLU and its metabolite (5-hydroxy flunixin; 5-OH) after subcutaneous (SC) and intravenous (IV) administration of single and multiple flunixin meglumine (FM) doses to non-lactating (nulliparous and pregnant does) and lactating dairy goats. Analytical methods (ELISA and UPLC-MS/MS) for quantifying plasma FLU concentrations were compared. The final objective was to use regulatory (FDA and EMA) methods to estimate milk withdrawal intervals following extra-label drug use in goats. Methods: FM was administered IV and SC to commercial dairy goats at 1.1 mg/kg for single and multiple doses. Plasma and milk samples were analyzed for FLU and 5-OH via UPLC-MS/MS. Plasma samples were also analyzed for FLU concentrations via ELISA. Using statistical approaches recommended by regulatory agencies, milk withdrawal intervals were estimated following FM extra-label use. Results: Following IV administration of a single FM dose, clearances were 127, 199, and 365 ml/kg/h for non-lactating (NL) pregnant does, NL nulliparous does, and lactating dairy does, respectively. Following multiple SC doses, clearance/F was 199 ml/kg/h for lactating does. After IV administration of a single FM dose, terminal elimination half-lives were 4.08, 2.87, and 3.77 h for NL pregnant does, NL nulliparous does, and lactating dairy does, respectively. After multiple SC doses, the terminal elimination half-life was 3.03 h for lactating dairy does. No significant differences were noted for samples analyzed by UPLC-MS/MS or ELISA. Milk withdrawal intervals ranged from 36 to 60 h depending on the regulatory statistical method and dosage regimen. Conclusions: Subcutaneous administration of FM to goats results in similar plasma pharmacokinetic parameters as IV administration. ELISA analysis is an alternative method to UPLC-MS/MS for quantifying FLU concentrations in caprine plasma samples. Following FM extra-label administration to dairy goats, clinicians could consider 36-60 h milk withdrawal intervals.

Detection and quantification of residues in sheep exposed to trace levels of dietary zilpaterol HCl.

Study objectives were to determine zilpaterol residues in urine and tissues of sheep fed dietary zilpaterol HCl, at levels commensurate with feed contamination, using common and novel screening and quantitative analytical methods. Sheep (50.0 ± 2.7 kg) were offered feed (1.75 kg/d) containing 0.0075 (L), 0.075 (M), or 0.75 (H) mg kg-1 of zilpaterol for 12 days and were slaughtered with 0-day (L-0, M-0, H-0; n = 4 each) or 3-day (H-3; n = 4) withdrawal periods. Rapid immunochromatographic assays (ICA) consistently detected urinary zilpaterol (LOD = 1.7 ng mL-1) in L-0 (54.2%), M-0 (96.0%), and the H-0 (100%) treatment groups but only detected zilpaterol in tissues (LOD ~2.4 ng g-1) from the H-0 group. Advanced MS-based technologies detected zilpaterol in some, but not all, tissues of M-0, H-0, L-0, and H-3 sheep. Analytical techniques commonly used to ensure compliance with show-animal rules, import/export guidelines, and regulatory statutes routinely detected residues in animals exposed to zilpaterol at doses insufficient to elicit growth responses.

Assessment of veterinary drugs present in pork kidney from a Midwest US retail market.

A total of 1040 pork kidneys were purchased from 4 retail stores located in a Midwestern US town and screened for antibiotics with the Charm-KIS™ screening test. Six samples (0.6%) tested positive with the Charm-KIS™. Sixty-five samples from each retail location and the 18 Charm-KIS™ positive or 'caution' samples were also subjected to ELISA to determine the presence of commonly used veterinary drugs including flunixin, ractopamine, sulfamethazine, and/or tetracycline of the 278 samples assessed by ELISA, flunixin, ractopamine, sulfamethazine, and tetracycline residues were found to be 0%, 22%, 4%, and 10% ELISA positive respectively, and had greater than limit of quantitation concentrations as measured by LC-MS/MS.  All residue levels determined by LC-MS/MS were well below US tolerances, regardless of analyte.  These findings suggest that veterinary drugs are being used in accordance with US regulations and that veterinary drug residues in pork do not pose a health concern to US consumers.

Atmospheric Solid Analysis Probe and Modified Desorption Electrospray Ionization Mass Spectrometry for Rapid Screening and Semi-Quantification of Zilpaterol in Urine and Tissues of Sheep.

Ambient ionization mass spectrometric methods including desorption electrospray ionization (DESI) and atmospheric solid analysis probe (ASAP) have great potential for applications requiring real-time screening of target molecules in complex matrixes. Such techniques can also rapidly produce repeatable semiquantitative data, with minimal sample preparation, relative to liquid chromatography-mass spectrometry (LC-MS). In this study, a commercial ASAP probe was used to conduct both ASAP-MS and modified DESI (MDESI) MS analyses. We conducted real-time qualitative and semiquantitative analysis of the leanness-enhancing agent zilpaterol in incurred sheep urine, kidney, muscle, liver, and lung samples using ASAP-MS and MDESI MS. Using ASAP, limits of detection (LOD) and quantitation (LOQ) in urine were 1.1 and 3.7 ng/mL, respectively, while for MDESI MS they were 1.3 and 4.4 ng/mL, respectively. The LODs for tissues were 0.1-0.4 ng/g using ASAP, and 0.2-0.6 ng/g with MDESI MS. The LOQs of the tissues in ASAP were 0.4-1.2 ng/g and 0.5-2.1 ng/g in MDESI MS. Trace levels of zilpaterol were accurately analyzed in urine and tissues of sheep treated with dietary zilpaterol HCl. The correlation coefficient ( R2) between semiquantitative ASAP-MS and MDESI MS results of urine samples was 0.872. The data from ASAP and MDESI MS were validated using LC-MS/MS; urinary zilpaterol concentrations ≥5.0 ng/mL or tissue zilpaterol concentrations ≥1.5 ng/g were detected by ASAP and MDESI MS, respectively, 100% of the time. Forty samples could be analyzed in triplicate, directly from biological matrixes in under an hour.

Development of an immunochromatographic assay for the ß-adrenergic agonist feed additive zilpaterol.

Zilpaterol is a ß-adrenergic agonist feed additive approved in the United States to increase weight gain and improve feed efficiency of cattle. A zilpaterol immunochromatographic assay was developed as an economical and user-friendly rapid detection method for zilpaterol and validated using urine and tissue samples derived from animal studies. The assay sensitivity was 1.7-23.2 ng g-1 or mL-1 across a variety of feed and animal matrices and did not cross-react with clenbuterol or ractopamine. No sample pre-treatment of cattle and sheep urine was needed, but horse urine and feed required dilution; skeletal muscle required solvent extraction prior to testing. Of 32 incurred sheep urine samples tested, zilpaterol content was correctly identified in all but 2 samples. Horse urine containing >10 ng mL-1 of incurred zilpaterol residue (n = 48) was correctly identified as zilpaterol positive. The assay correctly identified 0-day withdrawal sheep muscle samples as zilpaterol positive and the control and longer withdrawal day sheep muscle samples as negative. Zilpaterol was demonstrated to be stable in horse urine when stored at -20°C for 7 years.

Fluorescent microarray for multiplexed quantification of environmental contaminants in seawater samples.

The development of a fluorescent multiplexed microarray platform able to detect and quantify a wide variety of pollutants in seawater is reported. The microarray platform has been manufactured by spotting 6 different bioconjugate competitors and it uses a cocktail of 6 monoclonal or polyclonal antibodies raised against important families of chemical pollutants such as triazine biocide (i.e. Irgarol 1051®), sulfonamide and chloramphenicol antibiotics, polybrominated diphenyl ether flame-retardant (PBDE, i.e. BDE-47), hormone (17ß-estradiol), and algae toxin (domoic acid). These contaminants were selected as model analytes, however, the platform developed has the potential to detect a broader group of compounds based on the cross-reactivity of the immunoreagents used. The microarray chip is able to simultaneously determine these families of contaminants directly in seawater samples reaching limits of detection close to the levels found in contaminated areas (Irgarol 1051®, 0.19 ±â€¯0,06 µg L-1; sulfapyridine, 0.17 ±â€¯0.07 µg L-1; chloramphenicol, 0.11 ±â€¯0.03 µg L-1; BDE-47, 2.71 ±â€¯1.13 µg L-1; 17ß-estradiol, 0.94 ±â€¯0.30 µg L-1 and domoic acid, 1.71 ±â€¯0.30 µg L-1). Performance of the multiplexed microarray chip was assessed by measuring 38 blind spiked seawater samples containing either one of these contaminants or mixtures of them. The accuracy found was very good and the coefficient of variation was < 20% in all the cases. No sample pre-treatment was necessary, and the results could be obtained in just 1 h 30 min. The microarray shows high sample throughput capabilities, being able to measure simultaneously more than 68 samples and screen them for a significant number of chemical contaminants of interest in environmental screening programs.

Distribution of Chemical Residues among Fat, Skim, Curd, Whey, and Protein Fractions in Fortified, Pasteurized Milk.

The distribution of 12 environmental contaminants or metabolites with diverse polarities (2,2',4,4',5-pentabromodiphenyl ether; bisphenol A; estrone; glyphosate; ß-hexabromocyclododecane; imidacloprid; 2,3',4,4',5-pentachlorobiphenyl; 3'-methylsulfone 2,2',4,5,5'-pentachlorobiphenyl; 1,2,7,8-tetrachlorodibenzo-p-dioxin; 2-hydroxy-1,3,7,8-tetrachlorodibenzo-p-dioxin; tetrabromobisphenol A; and triclocarban) among skim milk, fat, curd, whey, whey retentate, and whey permeate was characterized. Analysis of these compounds along with 15 drugs previously studied provided a robust linear model predicting the distribution between skim and fat and the chemical's lipophilicity (log P, r 2 = 0.71; log D, r 2 = 0.79). Similarly, distribution between curd and whey was correlated with lipophilicity (log P, r 2 = 0.63; log D, r 2 = 0.73). Phenolic compounds had less predictable distribution patterns based on their lipophilicities. Within the whey fraction, chemicals with greater lipophilicity are associated with whey proteins more than hydrophilic chemicals. The resultant model could help predict the potential distribution of chemical contaminants among milk products in cow milk, if present.

Distribution of Spiked Drugs between Milk Fat, Skim Milk, Whey, Curd, and Milk Protein Fractions: Expansion of Partitioning Models.

The distributions of eight drugs (acetaminophen, acetylsalicylic acid/salicylic acid, ciprofloxacin, clarithromycin, flunixin, phenylbutazone, praziquantel, and thiamphenicol) were determined in milk products (skim milk, milk fat, curd, whey, and whey protein) and used to expand a previous model (from 7 drugs to 15 drugs) for predicting drug distribution. Phenylbutazone and praziquantel were found to distribute with the lipid and curd phases (≥50%). Flunixin distribution was lower but similar in direction (12% in milk fat, 39% in curd). Acetaminophen, ciprofloxacin, and praziquantel preferentially associated with casein proteins, whereas thiamphenicol and clarithromycin associated preferentially to whey proteins. Regression analyses for log [milk fat]/[skim milk] and log [curd]/[whey] had r2 values of 0.63 and 0.67, respectively, with p of <0.001 for 15 drugs (7 previously tested and 8 currently tested). The robustness of the distribution model was enhanced by doubling the number of drugs originally tested.

Evaluation of a QuEChERS-like extraction approach for the determination of PBDEs in mussels by immuno-assay-based screening methods.

A sample preparation method was evaluated for the determination of polybrominated diphenyl ethers (PBDEs) in mussel samples, by using colorimetric and electrochemical immunoassay-based screening methods. Herein, a rapid procedure based on QuEChERS-like extraction approach followed by solid phase purification was optimized for PBDE extraction from mussel samples. The detection limits for colorimetric and electrochemical immunoassays, calculated as BDE-47 equivalent concentration, were 0.6ngg-1 and 1.1ngg-1, respectively. Real mussel samples, including a Certified Reference Material (CRM), were analyzed. The samples were measured by colorimetric and electrochemical immunoassays as well as by GC-MS. In comparison to GC-MS results, 106% and 102% relative accuracy were obtained for the colorimetric and electrochemical immunoassays, respectively. The proposed method could be useful for massive environmental campaigns, being able to rapidly detect possible polluted seafood samples.