Search

• Description of a new representation of non-targeted LC-MS data: Molecular Barcode™. • Similarity analysis of soy-, dairy- and animal tissue-based food products. • Rationale of a semi-targeted method to detect animal tissue. • Detection of animal tissue in food products, using p G+ and related fragments. • Discussion about possible applications of the presented convergent approach. There are various analytical techniques available to address the growing interest in the composition of food products. LC-HRMS(/MS) is the most comprehensive technique, providing detailed information at the molecular level. However, given the vast number of different molecules encountered in food products, it is important to obtain a global overview of the dataset before focusing on similarities and differences. Therefore, a convergent strategy was employed, going from non-targeted to targeted analysis, with insightful data representations, most notably Molecular Barcode. Additionally an intermediate, semi-targeted analysis was defined, aimed at the specific detection of animal tissue in food products, using p G+ and related fragments after all ion fragmentation. The use of Molecular Barcode as a starting point to obtain relevant molecular data was also demonstrated. In conclusion, the convergent approach facilitates the design of suitable targeted methods, either to discriminate between samples or to find a generic target. [ABSTRACT FROM AUTHOR]

Sample pretreatment is directly related to the accuracy and reproducibility of test results, simple and controllable sample pretreatment can greatly reduce analysis errors. Herein, MIL-88B–NH 2 was synthesized with a regular octahedral rigid framework structure and used as antibody carrier to develop an immunochromatographic assay (ICA) for the detection of sodium pentachlorophenol (PCP) in animal tissues. MIL-88B–NH 2 has superior molar absorption coefficient, ultrahigh antibody affinity, and extreme detection environmental tolerance, which were 1.57, 2.5, and 2 times higher than those of traditional colloidal gold, respectively. Therefore, even complex animal tissues can be detected by simple extraction without nitrogen blowing. Ultimately, the cut-off values of this method for pork, chicken and shrimp were 8/5/3 μg/kg, the limits of detection were 1.15/1.28/0.25 μg/kg. The recoveries ranged from 95.5% to 103.0%, with the coefficient of variation from 1.87% to 9.69%. A parallel analysis of 30 samples was confirmed by LC-MS/MS; the results showed a good correlation (R2 > 0.95), indicating the authenticity and reliability of the MIL-88B–NH 2 -ICA. This work provides a detection strategy with enhanced sensitivity and robustness and simplified sample pretreatment, which has broad application prospects. [Display omitted] • MIL-88B–NH 2 was synthesized with extreme detection environmental tolerance. • MIL-88B–NH 2 -ICA was firstly developed with simplified sample preparation for PCP in animal tissues. • The sensitivity of the proposed method was 3–100 times higher than that of the reported methods. [ABSTRACT FROM AUTHOR]

The excessive accumulation of antibiotic residue in animal-derived foods pose a threat to our heath. Therefore, it is necessary to establish a rapid, simple, effective, safe and highly sensitive lincomycin (LIN) residues detection method by high-performance liquid chromatography equipped with ultraviolet. Here, due to the weak UV absorption of LIN, the p -Toluenesulfonyl isocyanate (PTSI, has a strong UV absorption) was binded to the hydroxyl group of LINs by using pre-column derivatization method, improving the UV absorption of LIN. This 9-min-run analytical method detects and quantifies LIN residues with acceptable validation performance parameters in terms of sensitivity, selectivity, linearity, the limit of quantification, accuracy, and precision.Our result showed that the limits of detection and quantification for LIN in samples were 25–40 μg/kg and 40–60 μg/kg, respectively, under the optimized conditions. Furthermore, the LIN recoveries ranged from 72.4 % to 96.7 %; the determination coefficients were 0.9912–0.9996, and the relative standard deviations were 5.6 %-12.7 %. Therefore, the HPLC-UVD method for detecting LIN residues in animal-derived food products has been established. [ABSTRACT FROM AUTHOR]

Highlights • HILIC-MS/MS was used for the determination of 16 coccidiostats in muscle and eggs. • Good accuracy and remarkably low LOQs were achieved in very short analysis time. • 82 meat & egg samples were analysed through the Greek National Residue Control Plan. • New data were obtained regarding the occurrence of coccidiostat residues in Greece. Abstract A simple, sensitive and efficient confirmatory method was developed and validated for the determination of 16 coccidiostats in animal tissues and eggs using hydrophilic interaction liquid chromatography–tandem mass spectrometry (HILIC-MS/MS). The sample preparation consisted of a solid-liquid extraction with ACN and dispersive SPE cleanup with MgSO 4 and C 18. Analysis was realized in an Acquity BEH HILIC silica column, in SRM mode. Both positive and negative ionization was performed, using polarity switching. Isocratic elution was used with a mobile phase of ACN: aqueous ammonium formate 1 mM with 0.1% formic acid (80:20, v/v). Method validation was performed in eggs, poultry, bovine, ovine, porcine and rabbit tissue and exceptionally low LODs were achieved, varying from 0.004 μg kg−1 (decoquinate in porcine tissue) to 0.560 μg kg−1 (halofuginone in eggs). The developed methodology was applied in 82 muscle and egg samples through the Greek National Residue Control Plan for coccidiostats. [ABSTRACT FROM AUTHOR]

This review explores the possibilities to determine livestock consumption of genetically modified (GM) feeds/ingredients including detection of genetically modified organism (GMO)-related DNA or proteins in animal samples, and the documentary system that is in place for GM feeds under EU legislation. The presence and level of GMO-related DNA and proteins can generally be readily measured in feeds, using established analytical methods such as polymerase chain reaction and immuno-assays, respectively. Various technical challenges remain, such as the simultaneous detection of multiple GMOs and the identification of unauthorized GMOs for which incomplete data on the inserted DNA may exist. Given that transfer of specific GMO-related DNA or protein from consumed feed to the animal had seldom been observed, this cannot serve as an indicator of the individual animal's prior exposure to GM feeds. To explore whether common practices, information exchange and the specific GM feed traceability system in the EU would allow to record GM feed consumption, the dairy chain in Catalonia, where GM maize is widely grown, was taken as an example. It was thus found that this system would neither enable determination of an animal's consumption of specific GM crops, nor would it allow for quantitation of the exposure. [ABSTRACT FROM AUTHOR]

• Two enantiomers of clenbuterol in pig tissues are separated and quantified. • No reciprocal transformation of two enantiomers during pretreatment is observed. • Chirality distributions of clenbuterol in tissues of pigs are investigated. To establish and validate a simple and reliable analytical method for separation and determination of clenbuterol enantiomers (R -(-)-clenbuterol & S -(+)-clenbuterol) in animal tissues, and apply it to the enantioselective distribution of clenbuterol in Bama mini-pigs. A LC-MS/MS analytical method was developed and validated in positive multiple reaction monitoring mode with electrospray ionization. After perchloric acid deproteinization, samples were pretreated only by one step liquid–liquid extraction using tert -butyl methyl ether under strong alkaline condition. Teicoplanin was used as chiral selector and 10 mM ammonium formate methanol solution was used as mobile phase. The optimized chromatographic separation conditions were completed in 8 min. Two chiral isomers in 11 edible tissues from Bama mini-pigs were investigated. R -(-)-clenbuterol and S -(+)-clenbuterol can be baseline separated and accurately analyzed with a linear range of 5–500 ng/g. Accuracies ranged from −11.9–13.0% for R -(-)-clenbuterol and −10.2–13.2% for S -(+)-clenbuterol, intra-day and inter-day precisions were between 0.7 and 6.1% for R -(-)-clenbuterol and 1.6–5.9% for S -(+)-clenbuterol. R/S ratios in edible tissues of pigs were all significantly lower than 1. The analytical method has good specificity and robustness in determination of R -(-)-clenbuterol and S -(+)-clenbuterol in animal tissues, and can be used as a routine analysis method for food safety and doping control. There is a significant difference in R/S ratio between pig feeding tissues and pharmaceutical preparations (racemate with R/S ratio of 1), which makes it possible to identify the source of clenbuterol in doping control and investigation. [ABSTRACT FROM AUTHOR]

This work deals with the development of an impedance measurement system for the exposure of an animal tissue (e.g. sheep muscle tissue model) to pulsed electric field (PEF). When exposed to short electric pulse, disturbances on the membrane and intra cellular components occur, modifying the behavioral response of cells exposed to foreign small materials. The phenomenon is believed to affect the electrical impedance of the tissue. While the conventional frequency based impedance measurement may reveal the electrical properties on the steady state condition, the method have been found to be insufficient for identifying impedance undergoing such very short pulse. Furthermore, this method can only take place before and after PEF. New techniques based on the pulsed voltage and current measurements have been developed for capturing the properties. The presented measurement system is composed of stainless steel electrodes that are not only designed to deliver energy to the biological tissue but also as measurement electrodes. The influence of electric field intensity of four different levels was investigated. The measured electrical impedance during pulsing was then represented to a recovery rate. The rate is defined as the changes in electrical impedance toward the electrical impedance of tissue that served as a reference of untreated tissue. The results showed that an impedance changing as a characterization of PEF level has been detected. Experiment shows that the impedance drop significantly when the PEF rise and then gradually increase regardless PEF decrease rate. A larger PEF intensity has more influence to slower down the cell membranes recovery in the tissue. The larger the PEF intensity, the slower the impedance rate. [ABSTRACT FROM AUTHOR]

This study presents a polyethylene beads method for OBT determination in animal tissues and animal products for cases where the amount of water recovered by combustion is limited by sample size or quantity. In the method, the amount of water recovered after combustion is enhanced by adding tritium-free polyethylene beads to the sample prior to combustion in an oxygen bomb. The method reduces process time by allowing the combustion water to be easily collected with a pipette. Sufficient water recovery was achieved using the polyethylene beads method when 2 g of dry animal tissue or animal product were combusted with 2 g of polyethylene beads. Correction factors, which account for the dilution due to the combustion water of the beads, are provided for beef, chicken, pork, fish and clams, as well as egg, milk and cheese. The method was tested by comparing its OBT results with those of the conventional method using animal samples collected on the Chalk River Laboratories (CRL) site. The results determined that the polyethylene beads method added no more than 25% uncertainty when appropriate correction factors are used. [ABSTRACT FROM AUTHOR]

An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and time-resolved fluoroimmunoassay (TR-FIA) based on an anti- N -butylquinoxaline-2-carboxamide (BQCA) monoclonal antibody were standardized and validated for quinoxaline-2-carboxylic acid (QCA) screening in animal tissues and its performance were compared to HPLC. The sensitivities obtained for edible tissue extracts were 1.62 and 1.12 ng ml −1 for ic-ELISA and TR-FIA detection, respectively. Two samples were spiked with QCA and analyzed by both methods. The recovery values ranged from 92.6% to 112.2% and the coefficients of variation were less than 15% for QCA spiking into swine tissue samples at concentrations of 2.5–50.0 μg kg −1 . Excellent correlations ( r 2 = 0.987–0.996) of the ic-ELISA/HPLC and TR-FIA/HPLC data were observed for processed samples. The results demonstrated that the ic-ELISA and TR-FIA methods were rapid and accurate for the residue detection of QCA in animal tissues. [ABSTRACT FROM AUTHOR]

• A MIP column was prepared by packing polymyxin E-imprinted microspheres. • MIP column showed excellent stability, efficiency and selectivity to polypeptide antibiotics. • In-line MISPE allowed the screening of polypeptide antibiotics in animal tissue by LC-UV. • A LC-MS/MS method based on in-line MISPE for the analysis of polypeptide antibiotics was developed. • Obtained recoveries ranged from 66.7 to 94.5% and limits of detection were 3.0 ∼ 8.0 μg/kg. Effective purification and enrichment of polypeptide antibiotics in animal tissues is always a challenge, due to the co-extraction of other endogenous peptides which usually interfere their final determination. In this study, a molecularly imprinted column was prepared by packing polymyxin E-imprinted particles into a 100 mm × 4.6 mm i.d. HPLC column. The as-prepared imprinted columns were able to tolerate 100% aqueous phase and exhibited good stability and high column efficiency. Polypeptides antibiotics with similar molecular size or spatial structure to polymyxin E were well retained by the imprinted column, suggesting class selectivity. After optimization of mobile phase conditions of imprinted column, polypeptide antibiotics in animal tissue extracts were enriched and cleaned up by in-line molecularly imprinted solid-phase extraction, allowing the screening of target analytes in complex samples at low concentration levels by UV detection. Eluate fraction from the imprinted column was collected, and further dried and re-dissolved with methanol-0.5% formic acid aqueous solution (80:20, v/v) for final LC-MS/MS analysis. Analysis was accomplished using multiple reaction monitoring (MRM) in positive electrospray ionization mode and analytes quantified using the matrix-matched external calibration curves. The results showed high correlation coefficients for target analytes in the linear range of 2 ∼ 200 μg kg−1. At four different concentration levels (limit of quantification, 50, 100 and 200 μg kg−1), recoveries of four polypeptide antibiotics in swine, cattle and chicken muscles ranged from 66.7 to 94.5% with relative standard deviations lower than 16.0%. The limits of detection (LOD) were 2.0 ∼ 4.0 μg/kg, depending upon the analyte and sample. Compared with a conventional pretreatment method, the imprinted column was able to remove more impurities and to significantly reduce matrix effects, allowing the accurate analysis of polypeptide antibiotics. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To determine 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ) residues released from protein bound AMOZ in animal tissues. Methods: Polyclonal and monoclonal antibodies were produced in this study. A rapid, sensitive, and specific competitive direct enzyme-linked immunosorbent assay (cdELISA) was developed. Results: Rabbit polyclonal antibodies were used in the optimized cdELISA method, and exhibited negligible cross-reactivity with other compounds structurally related to AMOZ. The IC50 of the polyclonal antibody was 0.16 ng/mL. The method limit of detection in four different types of animal and fish tissues was less than 0.06 μg/kg. Recoveries ranged from 80% to 120% for fortified samples with the coefficient of variation values less than 15%. The results of the cdELISA method were in good agreement with the results from an established liquid chromatography-tandem mass spectrometry confirmatory method used for AMOZ residues. Conclusion: The cdELISA method developed in the present study is a convenient practical tool for screening large numbers of animal and fish tissue samples for the the detection of released protein bound AMOZ residues. [Copyright &y& Elsevier]

Abstract: A sensitive and specific enzyme-linked immunosorbent assay (ELISA) for the detection of 1-amino-hydantoin (AHD) is described. AHD, the marker residue for nitrofurantoin, is a tissue bound toxic metabolite. To monitor the illegal use of nitrofurantoin, a monoclonal antibody-based ELISA method was developed to detect AHD residue in animal tissues. The highly specific antibody against AHD was prepared by monoclonal antibody technology. The antibody exhibited negligible cross reactivity with other nitrofurans, their metabolites and derivatives, and 50% inhibitory concentration was 0.68 μg/L. The limit of detection in four kinds of animal tissues were all below 0.2 μg/kg and recoveries ranged from 75% to 116.7% for fortified samples at levels of 0.2–5 μg/kg with coefficient of variation values below 15%. Analysis of natural contaminated samples by the ELISA method gave similar results to those of the liquid chromatography-tandem mass spectrometry method. These results indicate the ELISA method is suitable for the detection of AHD residue in animal tissues. [Copyright &y& Elsevier]

Abstract: Aminoglycosides (AGs) are a large and diverse group of antibiotics. Although AGs may cause side effects of nephrotoxicity and ototoxicity, they are still occasionally being used for the treatment of serious infections. In this study the development of a method is described for the quantitative determination and confirmation of seven aminoglycosides (and relevant isomers) and spectinomycin in animal tissues. The extraction was based on an extraction followed by a concentration and clean-up step using weak cation exchange solid phase extraction. The separation was performed by ion-pair liquid chromatography on a C18 column followed by mass spectrometric detection. The method was validated according to the EU requirements for a quantitative confirmatory method. Permethylated aminoglycosides (in-house synthesised internal standards) were used for accurate quantification. The accuracy of the analyses of AGs in kidney ranged from 94 to 111%, intra-day precision ranged between 2.5 and 7.4% (R.S.D.r) and inter-day precision ranged between 2.2 and 17.3% (R.S.D.RL, n =21, MRL level). Accuracy (muscle tissue) varied from 83 to 128% with an intra-day precision between 2.2 and 17.3% (R.S.D.r, n =7, MRL level). From the results it was concluded that the method was able to monitor MRL levels which ranged from 750 to 20,000μgkg−1 for kidney and from 50 to 10,000μgkg−1 for muscle tissue. [Copyright &y& Elsevier]

[Display omitted] • A hydroxyethylmethacrylate-based copolymer was the most suitable replacement for porcine buccal tissue in adhesion testing. • Polyacrylic acid and polyvinylpyrrolidone significantly improve the adhesive properties of hypromellose-based films. • The measured detachment force and work of adhesion strongly depend on the method parameters. When developing buccal films for oromucosal drug administration, adhesion is essential to ensure sufficient time for permeation of the active ingredient(s) through the oral mucosa and avoid the detachment and subsequent swallowing of the film. In this study, biomimetic materials were evaluated as a replacement for buccal mucosa in mucoadhesion testing and potential adhesives were compared regarding their suitability to increase the adhesion of hypromellose-based oromucosal films. Gelatin gels, as possible biomimetics, failed to mimic the buccal mucosa. Furthermore, esophageal tissue lead to a wider variance of adhesion data despite showing a good correlation with buccal tissue. A synthetic copolymer hydrogel based on hydroxyethylmethacrylate (HEMA) and N-acryloyl glucosamine (AGA) was able to mimic the buccal mucosa in these tests and reduced the variation in the data compared to animal tissue. Adding polyacrylic acid and polyvinylpyrrolidone to the film formulations at a concentration of 5% w/w approximately doubled the maximum detachment force and work of adhesion. Sodium alginate enhanced the adhesive properties moderately but adding chitosan did not significantly increase mucoadhesion. Polyvinylpyrrolidone and polyacrylic acid are rated as strong adhesion enhancers for buccal films and the HEMA/AGA hydrogel is considered as a suitable alternative for animal mucosa in mucoadhesion testing. [ABSTRACT FROM AUTHOR]

Abstract: Thermal expansion data are essential for thermal stress analysis in order to predict the likelihood of fracture formation in tissues during cryopreservation as well as cryosurgery. The current study focuses on examining the thermal expansion behavior of rabbit aorta during freezing, especially phase change processes. Thermo mechanical analysis (TMA) was used to investigate the effects of different concentrations of dimethyl sulfoxide (DMSO) cryoprotective agent (CPA) (0%, 5%, 10%, and 15% (v/v) DMSO) and different freezing rates (3, 5 and 10°C/min). The results showed that (1) the maximum of thermal strain for 10°C/min was approximately four times greater than that for 3°C/min, and 1.4 times greater than that for 5°C/min, and the higher the freezing rate, the larger the corresponding thermal expansion coefficient; (2) the maximum thermal strain of sample permeated by 5% DMSO approached that of 0% DMSO (i.e., no DMSO was added); however, it showed very significant difference from that of 15% DMSO (only half of that with 5% DMSO), and the thermal expansion coefficient decreased when the concentration of DMSO solution increased; (3) comparison with data available from the literature and with theoretically calculated values illustrated that the thermal expansion change was not equal to the volume change from free water to ice during freezing, but was related to the freezing rate of samples and the DMSO concentration. [Copyright &y& Elsevier]

Abstract: A liquid chromatographic (LC)–tandem mass spectrometry (MS/MS) method was developed for simultaneous determination of stilbenes, diethylstilbestrol (DES), hexestrol (HEX), and dienoestrol (DEN) in animal tissue. Sample clean-up and analyte enrichment was performed by automated solid-phase extraction (ASPE) with a silica gel cartridge. Detection capabilities (CCβ) related to the transition products of lowest abundance for the method were 0.04–0.45ngg−1 in tissue and were achieved using atmospheric pressure chemical ionization (APCI) in negative mode. The use of an internal standard in combination with the simplified sample preparation led to a sensitive and reliable analytical method. The recovery level of the method was 84–108% for DES and DEN between 0.5 and 5ngg−1, and 59–87% for HEX between 0.25 and 2.5ngg−1. [Copyright &y& Elsevier]

Abstract: Aim: To determine whether universal molecular fixative (UMFIX), a novel human tissue fixative, could also be used as an animal tissue fixative for histomorphology and a preservative of RNA at subtropical temperatures. Cat, dog, mouse, pigeon, rabbit and rat tissue, as well as ant, beetle, earthworm and lizard were collected. Tissue was fixed in UMFIX for up to a week at room or ambient temperatures, processed and paraffin embedded. Histomorphology and RNA quality were evaluated and compared to formalin-fixed and fresh frozen tissue. Results: Animal tissue fixed in UMFIX at room temperature or high ambient temperature (30–34°C) provides similar histomorphology. Comparable to other alcohol-based fixatives, UMFIX produces a histomorphology similar but not identical to formalin. All minor histopathological differences, however, in no way interfere with establishing the correct diagnostic conclusion. Whereas RNA extracted from animal tissue fixed in formalin was completely degraded, tissue fixed up to 1 week in UMFIX at high ambient temperatures rendered completely intact RNA. Conclusions: UMFIX represents a new class of preservative/fixative that protects RNA and provides acceptable histomorphology. Tissue fixation and preservation of RNA can be achieved at high ambient temperatures. This allows collection of animal tissue in field research without the need for immediate freezing of tissue and also provides histomorphology comparable to formalin-fixed tissue. Furthermore, as RNA is also preserved in UMFIX preserved paraffin-embedded tissue, if amount of tissue is limited the same tissue that is used to determine histomorphology can be used to extract RNA. [Copyright &y& Elsevier]

Abstract: We present terahertz time-domain spectroscopy characterization of various animal tissues obtained from pork and rats. As the sensitivity of terahertz radiation to polar molecules of water is very high, biological tissues with high level of hydration show strong absorption at terahertz frequencies. The experimental data indicate that skin, fat and lean pork tissues have different frequency-dependent response to terahertz radiation due to the variation in water content. The same type tissue from different animals, however, is observed to show very similar water absorption. [Copyright &y& Elsevier]

Abstract: A new method based on natural animal tissue porcine kidney as recognition element for chemiluminescence sensing of lactic acid is proposed in this paper. The principle for lactic acid sensing is that lactic acid is oxidized by oxygen under the catalysis of α-hydroxy acid oxidase in the tissue column to produce hydrogen peroxide, which can react with luminol in the presence of potassium ferricyanide to generate a CL signal. The experimental results show that the CL emission intensity was linear with lactic acid concentration in the range of 1–1000μmol/L and the detection limit (3σ) for lactic acid was 0.2μmol/L. The biosensor could be used continuously for 6h with no significant changes in the response. More than 240 measurements were carried out during this time. A complete analysis, including sampling and washing, could be performed in 1.5min with a relative standard deviation of 1.12% for 100μmol/L lactic acid. The reproducibility among tissue columns was satisfactory (RSD among columns is less than 5%). The biosensor has been applied successfully to the analysis of lactic acid in plasma and milk samples. [Copyright &y& Elsevier]

The pharmacokinetics of amoxicillin (Amx) were determined in pigs following intravenous (IV) administration of a single dose of 15 mg/kg and a single dose of 15 mg/kg of a new oral formulation (Amx-FP containing 10% amoxicillin). Residue studies were performed to determine residues in edible tissues of healthy pigs after chronic oral administration of Amx-FP at a daily dose of 15 mg/ kg for five consecutive days. After IV administration, the plasma concentration was characteristic of a two-compartment open model. The main pharmacokinetic variables were: t1/2λn = 82.5 min, MRT = 90.1 min, Vdarea = 0.81 L/kg and Clb = 3.9 mL/kg/min. After single oral administration the main pharmacokinetic variables were: Cmax = 758 µg/L, tmax = 347 min and Clb/f = 3.7 mL/kg/min for Amx-FP. The oral bioavailability (F) was calculated at 11% for Amx-FP. Based on maximum residue levels (MRL) for AMX in pigs established at 50 micro;g/kg for all tissues, the withdrawal times of AMX in muscle and skin plus fat were estimated (95% tolerance limit and 95% confidence) to fall below the MRL after a withdrawal period of seven days. Levels of AMX in the liver and kidneys were estimated to fall below the MRL after a withdrawal period of four days. [ABSTRACT FROM AUTHOR]

Abstract: A new flow injection analysis method based on animal tissue as recognition element for chemiluminescence sensing of uric acid is proposed in this paper. The liver of the large white pig was used as molecular recognition element. Uric acid is oxidized by oxygen under the catalysis of urate oxidase in the tissue column to produce hydrogen peroxide, which can react with luminol in the presence of potassium hexacyanoferrate(III) to generate a CL signal. The experimental results show that the CL emission intensity was linear with uric acid concentration in the range of 0.001–3μgmL-1 and the detection limit (3σ) for uric acid was 4×10-4μgmL-1. The biosensor detection system could be used continuously for 4h with less than 10% decrease in the response. More than 200 measurements were carried out during this time. A complete analysis, including sampling and washing, could be performed in 1min with a relative standard deviation of 4.47% for 1μgmL-1 uric acid. The biosensor detection system has been applied successfully to the analysis of uric acid in plasma and urine samples. [Copyright &y& Elsevier]

Iron has been widely studied in nearly every realm of biology. However, current methodologies, such as genetic mapping or mutation screening, have been difficult to apply due to the lack of robust high-throughput methods for quantifying iron levels from cells or tissues. The measurement of total iron levels in tissues, usually done with atomic absorption spectroscopy, is impractical for large numbers of samples and includes the contribution of heme iron from hemoglobin contained in red blood cells. The measurement of non-heme iron by reaction with a bathophenanthroline reagent, a commonly used assay reported more than 30 years ago, is also not feasible for large-scale analyses because it is cuvette-based. We therefore have modified this method to a microplate format that will facilitate large-scale analysis. The microplate assay is highly sensitive and specific, and is a simple and effective method for the measurement of non-heme iron for animal tissues that will enable the application of high-throughput of genetic methodologies. [Copyright &y& Elsevier]

In the present study, we evaluated a microwave digestion procedure followed by electrothermal atomic absorption spectrometry (ET-AAS) for the determination of the platinum group metals (PGM) Pt, Pd and Rh in small amounts of animal tissue. Due to the lack of certified biological standard reference materials for PGM, we performed interlaboratory comparisons using adsorptive cathodic stripping voltammetry (ACSV) after digestion of the samples by high pressure ashing (HPA) for the determination of Pt and Rh and total-reflection X-ray fluorescence (TXRF) analysis after co-precipitation of Pd with mercury for the determination of Pd, as reference methods. Suitable sample materials were obtained from laboratory experiments with mussels exposed to PGM salts or ground automobile catalytic converter material.The 3 s detection limits for microwave digestion (MWA)/ET-AAS were 270 ng g−1 (Pt), 90 ng g−1 (Pd) and 13 ng g−1 (Rh), the precision was better than 10% and the recovery was >95%. The highest divergence between the MWA/AAS and HPA/ACSV/TXRF procedures was found for Pt with values of 48 and 26%. But, even though the Pt levels exceeded the detection limit, the concentrations were near to or below the limit of determination (three times the detection limit). In contrast to Pt, the results of the different analytical procedures for Pd and Rh were comparable (<20% deviation).The combination of MWA and ET-AAS is a very rapid and relatively cheap method for routine PGM analysis in large numbers of animal tissue samples with PGM concentrations exceeding the upper ng g−1 range as occur e.g. in experimental studies or in the medical sector after treatment with Pt-anti-cancer drugs. [Copyright &y& Elsevier]