High-performance Liquid Chromatography With Fluorescence Detection Research Articles

Natural occurrence of ochratoxin A in wolfberry fruit wine marketed in China

Wolfberry fruit wine (WFW) is widely used as a global functional food to improve the immune system and prevent human disease. A total of 36 bottled WFWs were randomly collected in China between 2005 and 2010. Samples were analysed for the presence of ochratoxin A (OTA) using immunoaffinity column (IAC) clean-up and high-performance liquid chromatography with fluorescence detection (HPLC-FLD). Positive results were confirmed by liquid chromatography–electrospray ionisation–tandem mass spectrometry (LC-ESI-MS/MS). The limit of detection (LOD), based on a signal-to-noise ratio of 3, was 0.05 ng mL–1. Recoveries ranged from 78.3% to 94.7% and relative standard deviations from 1.1% to 4.3% within the spiking range of 0.2–20 ng mL–1. OTA was detected in one sample, below the maximum allowable limit as established by the European community.

Aflatoxin M1 and ochratoxin A in baby formulae in Turkey: Occurrence and safety evaluation

During 2011, 62 samples of baby formulae were checked for aflatoxin M1 (AFM1) and ochratoxin A (OTA) by immunoaffinity column (IAC) clean-up and high performance liquid chromatography with fluorescence detection (HPLC-FD). The limits of detection (LOD) and quantification (LOQ) of the analytical method were 0.005 μg kg−1 and 0.018 μg kg−1 for AFM1 and 0.006 μg kg−1 and 0.021 μg kg−1 for OTA, respectively. The recovery of AFM1 from formulae ranged between 84.27% and 88.21% (RSD = 3.54–6.18%), while the mean recoveries of OTA varied from 79.21% to 86.38% (RSD = 4.47–7.11%).Aflatoxin M1 was detected in five (8%) of formula samples, but at levels below the European legislation limit of 0.025 μg kg−1, with concentrations ranging from 0.016 to 0.022 μg kg−1 (mean level: 0.018 μg kg−1). Ochratoxin A was detected in 12 out of the 62 samples (19.4%), at levels ranging from 0.017 to 0.184 μg kg−1 (mean level: 0.103 μg kg−1). None of the samples exceeded the maximum limit for OTA set by European Commission Regulation (0.5 μg kg−1). The co-occurrence of AFM1 and OTA was present in only one sample (1.6%). The estimated daily intakes of AFM1 and OTA through formulae were in the range of 0.08–0.021 ng kg−1 b.w. and 0.034–0.305 ng kg−1 b.w., respectively. On the basis of current knowledge, it can be concluded that there is no considerable risk of AFM1 and OTA exposure for the Turkish babies and young children.

Polycyclic aromatic hydrocarbons (PAHs) in lake sediments record historic fire events: Validation using HPLC-fluorescence detection

Understanding the natural mechanisms that control fire occurrence in terrigenous ecosystems requires long and continuous records of past fires. Proxies, such as sedimentary charcoal and tree-ring fire scars, have temporal or spatial limitations and do not directly detect fire intensity. We show in this study that polycyclic aromatic hydrocarbons (PAHs) produced during wildfires record local fire events and fire intensity. We demonstrate that high performance liquid chromatography with fluorescence detector (HPLC-FLD) is superior to gas chromatography–mass spectrometry (GC–MS) for detecting the low concentrations of sedimentary PAHs derived from natural fires. The HPLC-FLD is at least twice as sensitive as the GC–MS in selective ion monitoring (SIM) mode for parent PAHs and five times as sensitive for retene. The annual samples extracted from varved sediments from Swamp Lake in Yosemite National Park, California are compared with the observational fire history record and show that PAH fluxes record fires within 0.5km of the lake. The low molecular weight (LMW) PAHs (e.g., fluoranthene, pyrene and benz[a]anthracene) are the best recorders of fire, whereas the high molecular weight (HMW) PAHs likely record fire intensity. PAHs appear to resolve some of the issues inherent to other fire proxies, such as secondary deposition of charcoal. This study advances our understanding of how PAHs can be used as markers for fire events and poses new questions regarding the distribution of these compounds in the environment.

Facile synthesis of magnetic one-dimensional polyaniline and its application in magnetic solid phase extraction for fluoroquinolones in honey samples

In this work, we proposed a simple co-mixing method to fabricate magnetic one-dimensional polyaniline (denoted as 1D-PANIs/MNPs). One-dimensional polyanilines (1D-PANIs) and magnetic nanoparticles (MNPs) were prepared by chemical oxidation and solvothermal methods, respectively. When MNPs and 1D-PANIs (with mass ratio 4:1) were co-mixed and vortexed evenly in a solvent (e.g., ethanol, water, acetonitrile), they could assemble into 1D-PANIs/MNPs spontaneously and thus be magnetically separable. To testify the feasibility of 1D-PANIs/MNPs in sample preparation, it was applied as the sorbent for magnetic solid phase extraction (MSPE) of fluoroquinolones (FQs) in honey samples. Under optimized conditions, a rapid, convenient, and efficient method for the determination of four FQs in honey samples by 1D-PANIs/MNPs-based MSPE coupling with high performance liquid chromatography with fluorescence detection (HPLC-FLD) was established. The limits of detection (LODs) for four FQs ranged from 0.4 to 1.4ngg−1. The intra- and interday relative standard deviations (RSDs) were less than 17.6%. The recoveries of FQs for three spiked honey samples ranged from 86.3 to 121.3%, with RSDs of less than 16.3%.

Tolerance and pharmacokinetics of single-dose intravenous hemoporfin in healthy volunteers

To investigate the safety, tolerability and pharmacokinetics of intravenous hemoporfin, a novel photosensitive drug for the treatment of port-wine stain (PWS), in healthy Chinese volunteers following single-dose administration. Thirty-six healthy Chinese subjects were enrolled. The subjects were administered hemoporfin (2.5, 5, 7.5 or 10 mg/kg) via single-dose intravenous infusion. Pharmacokinetics of the drug were studied in the groups with doses of 2.5, 5 and 7.5 mg/kg, and tolerability was studied in all the 4 groups. Safety and tolerance were evaluated by monitoring adverse events and laboratory parameters, and pharmacokinetics were assessed by determining hemoporfin content with a validated high-performance liquid chromatography with fluorescence detection (HPLC/FLD) method. Mild and transient adverse events occurred in the trial (n=10), but none were serious, and no subjects were withdrawn from the trial. The gastrointestinal tract adverse events, such as nausea, stomach upset, abdominal pain and vomiting, were observed in the groups with doses of 7.5 and 10 mg/kg. Increased alanine aminotransferase (ALT) concentration was found in 3 subjects, and increased alkaline phosphatase (ALP) concentration in one subject. The half-life of hemoporfin for doses of 2.5, 5, and 7.5 mg/kg was 1.26 h, 1.31 h, and 1.70 h, respectively. C(max) and AUC increased with dose for intravenous single-dose administration of hemoporfin in the 2.5, 5, and 7.5 mg/kg groups. Urinary excretion of hemoporfin within 12 h was less than 0.2%. Hemoporfin is safe and well-tolerated in healthy Chinese volunteers at a single intravenous dose of up to 10 mg/kg. It was rapidly cleared from the blood and had a short half-life, which insures a short light-avoidance period.

Simultaneous Determination of Free Amino Acid Content in Tea Infusions by Using High-Performance Liquid Chromatography with Fluorescence Detection Coupled with Alternating Penalty Trilinear Decomposition Algorithm

In this paper, a novel application of alternating penalty trilinear decomposition (APTLD) for high-performance liquid chromatography with fluorescence detection (HPLC-FLD) has been developed to simultaneously determine the contents of free amino acids in tea. Although the spectra of amino acid derivatives were similar and a large number of water-soluble compounds are coextracted, APTLD could predict the accurate concentrations together with reasonable resolution of chromatographic and spectral profiles for the amino acids of interest owing to its "second-order advantage". An additional advantage of the proposed method is lower cost than traditional methods. The results indicate that it is an attractive alternative strategy for the routine resolution and quantification of amino acids in the presence of unknown interferences or when complete separation is not easily achieved.

Determination of serum aromatic amino acid in patients with CRI by high performance liquid chromatography with fluorescence detection

Objective A HPLC-FLD method was developed to determine the levels of serum AAA in CRI patients, and to study the variation of serum AAA in CRI patients and its clinical significances. MethodsSerum samples were collected from 100 health controls and 80 CRI patients. According to 2002 National Kidney Foundation (NKF) staging diagnosis, CRI patients included 4 of stage 2, 12 of stage 3, 12 of stage 4, 52 of stage 5. According to pathogenesis, CRI patients were also divided into 3 groups :chronic nephritis group ( n = 32), DM group ( n = 36), hypertension group ( n = 12 ).Serums were deproteinized by equal volume of 5％ (v/v) PCA and supernate were analyzed direcdy. External standard method was used as quantitative method. The analytical column was Megres C18. 10％ acetonitrile in water was used as mobile phase. Flow rote was 1.0 ml/min. The wavelengths of fluorescence excitation and emission were changed with specific time. The levels of Tyr, Phe and Trp in CRI groups, different CKD stages and different pathogenesis were compared with healthy control groups to evaluated the sensitivity and specificity of serum AAA for CRI diagnosis. Results The linear ranges of the method were 0. 550 -275.000, 3. 050 - 1220. 000 and 0. 049 -49. 000 pμmol/L for Tyr, Phe and Trp, respectively. The limit of detection (LOD) was 0.014 μmol/L for Tyr, 0.500μmol/L for Phe, and 0.005 μmol/L for Trp. The average recovery was 100. 9％, 101.3％ and 98. 5％ for Tyr, Phe and Trp, respectively. Intra-day CVwas 3. 18％ -4. 20％ ( mean was 3. 13％ )and inter-day CV was 3. 18％ -4. 20％ ( mean was 3. 58％ ). The concentration of serum AAA, Tyr and Trp and the ratio of Tyr/Phe in CRI patients were( 135.74 ±23.23 )μmol/L, (52.27 +8.25) μmol/L, (21.49 ±4.25) μmol/L and[0.87(0.68 - 1.05)]μmol/L. which were lower than that in healthy groups (t value was -14. 709, 4.452, 22. 100, U value was 266.000,respectively, P＜0. 05). The concentration of serum AAA, Tyr and Trp and the ratio of Tyr/Phe in healthy groups were ( 174. 47 ± 11.57 ) μmol/L, ( 63.53 ± 4. 68 ) μmol/L, (44. 22 ± 3. 67 ) μmol/L and[0. 97(0. 94 - 1.00)]μmoL/L. There were no statistically significant difference between the different stage of CRI. Compared with the concentration of Tyr, Phe and Trp among chronic nephritis group, DM group,hypertension group, the concentration of Tyr had no significant changes among these three kinds of diseases (P ＞ 0. 05 ). The concentration of Phe had significant changes between Chronic nephritis group and DM group, Chronic nephritis group and hypertension group ( U = 395.00, 114. 00, P ＜ 0. 05 ) ; the concentration of Trp haad significant changes between Chronic nephritis group and DM group ( U = 349.00, P ＜ 0. 05 ).The diagnostic sensitivity and specificity of serum AAA for CRI were 90％ (72/80) and 100. 0％ (100/100).Conclusions The method of high-performance liquid chromatography with fluorescence detection ( HPLC-FLD) is simple, rapid, sensitive and specific. Simultaneous determination of serum AAA was benefit to the diagnosis and evaluation of CRI patients. Key words: Renal insufficiency, chronic; Amino acids, aromatic; Chromatography, high pressure liquid

Residues of fluoroquinolones in marine aquaculture environment of the Pearl River Delta, South China

Concentrations and distributions of selected fluoroquinolones (norfloxacin, ciprofloxacin and enrofloxacin) in water, sediments and nine kinds of fish species collected from 6 sites in two marine aquaculture regions of the Pearl River Delta, China, were analyzed by using high-performance liquid chromatography with fluorescence detector (HPLC). The results showed that the concentrations of ciprofloxacin and enrofloxacin were below the limits of quantification (LOQ) in all water samples except for norfloxacin. Norfloxacin and ciprofloxacin concentrations ranged from 1.88 to 11.20 ng g(-1) dry wt, 0.76-2.42 ng g(-1) dry wt in sediments collected from the Dapeng'ao region (sites 1-3) and ranged from 2.31 to 4.75 ng g(-1) dry wt, 1.26-1.76 ng g(-1) dry wt in sediments collected from the Hailing Island region (sites 4-6), respectively. However, no enrofloxacin was found in all sediment samples. The three fluoroquinolones (FQs) were detected in all fish samples, and the concentrations were higher in liver tissues than those in muscle tissues. The levels of norfloxacin were higher than ciprofloxacin and enrofloxacin in both liver and muscle tissues. Among the nine marine fish species, Siganus fuscescens from Hailing Island had a significantly high level of norfloxacin in liver tissue (254.58 ng g(-1) wet wt), followed by Sparus macrocephalus (133.15 ng g(-1) wet wt) from Dapeng'ao, and the lowest value was Lutianus argentimaculatus (5.18 ng g(-1) wet wt) from Hailing Island. The obtained results of FQs in present study do not represent a risk to the human health in Guangdong coastal area, based on the maximum residue limits (MRLs) established by Chinese Government and the acceptable daily intake (ADI) recommended by the Food and Agriculture Organization and World Health Organization (FAO/WHO).

HPLC-FLD simultaneous determination of 13 polycyclic aromatic hydrocarbons: validation of an analytical procedure for soybean oils

. A method using high performance liquid chromatography with fluorescence detection (HPLC-FLD) was developed for the simultaneous determination of 13 polycyclic aromatic hydrocarbons (PAHs) in soybean oils. The sample preparation includes liquid-liquid extraction with dimethylformamide-water (9:1, v/v) followed by a clean-up and concentration step with C-18 SPE cartridges. The method showed good recoveries for most of the PAHs studied with values between 71 and 115%. The calibration curves were linear over the range tested (R 2 > 0.999). Detection and quantification limits varied between 0.02-0.76 µg kg -1 and 0.03-0.96 µg kg -1 , respectively. The analytical procedure was successfully applied to evaluate the contamination of most consumed brands of soybean oils commercially available in the Brazilian market. The presence of PAHs was confirmed in all samples analyzed with mean values ranging from 0.20 to 5.93 µg kg -1 .

Occurrence of aflatoxin B1 and ochratoxin A in Lebanese cultivated wheat

An extensive survey of filamentous fungi isolated from wheat grown and consumed in Lebanon and their capacity to produce aflatoxin B1 (AFB1) and ochratoxin A (OTA) was conducted to assess fungi potential for producing these toxins in wheat. From the 468 samples of wheat kernel, collected at preharvest stage from different locations during 2008 and 2009 cultivation seasons, 3,260 fungi strains were isolated with 49.4% belonging to Penicillium spp. and 31.2% belonging to Aspergillus spp. Penicillium spp. was detected on wheat samples with a high amount of P. verrucosum (37.0%). Among the different Aspergillus spp. isolated, A. niger aggregate was predominant and constituted 37.3%. whereas the isolation rate of A. flavus and A. ochraceus was 32.2 and 25.6%, respectively. The ability to produce OTA and AFB1 by isolates belonging to Aspergillus spp. and Penicillium spp. was analyzed by high performance liquid chromatography with fluorescence detector (HPLC-FLD). It was found that 57.0% of Penicillium spp. and 80% of A. ochraceus isolates tested produced OTA, respectively, at maximum concentrations of 53 and 65μg/g CYA. As for the aflatoxinogenic ability, 45.3% of A. flavus produced AFB1, with maximum concentration of 40μg/g CYA. A total of 156 wheat samples were analyzed for the levels of OTA and AFB1 by HPLC-FLD. The results showed that 23.7% were contaminated with OTA, at a concentration higher than 3μg/kg and 35.2% of these samples were contaminated with AFB1 at concentration higher than 2μg/kg. The risks originating from toxin levels in wheat produced in Lebanon should be monitored to prevent their harmful effects on public health.

Classification of anticancer drugs with different mechanisms based on amino-acid consumption profiling in culture media

An approach for quantitative determination of amino-acid consumption profiling in culture media by high performance liquid chromatography with fluorescence detection (HPLC-FLD) was developed and validated, using o-phthalic dicarboxaldehyde (OPA) as the derivatizing reagent and norvaline as the internal standard. Mobile phase A was 10 mmol/L Na2HPO4Na2B4O7 buffer (pH 7.95), and mobile phase B was acetonitrile-methanol-water (45:45:10, v/v/v). The linear elution program was 5% B at the start and 52% B at the end in 35 min. The 17 free amino-acids (FAAs) were separated satisfactorily in 33 min. Following HeLa cells incubation in conditioned medias of taxol (4 micromol/L) and mitomycin (75 micromol/L), respectively, with control for 24 h, the media 17 amino-acid consumption profilings were determined, and then analyzed by multivariate statistical analysis based on Matlab7.1 software platform. Relation analysis performed by partial least squares-discriminant analysis (PLS-DA) indicated that in comparison with the control group, the media amino-acid consumption profiling can distinguish the two anticancer drugs with different mechanisms, which provides a new perspective for the pre-classification of drug action mechanisms during the screening of new anticancer drugs. Meanwhile, the idea from the outer into the inner has convenient and economic characteristics.

곡류가공품 중 제랄레논 오염도 조사

시중 유통 중인 과자류, 빵, 떡류, 면류 및 선식 등 432건을 immunoaffinity column으로 정제하여 HPLC-FLD로 제랄레논에 대한 오염실태를 조사하였다. 제랄레논의 검량선은 결정계수(<TEX>$R^2$</TEX>)가 0.999 이상으로 양호한 직선성을 보였고 검출한계 및 정량한계는 각각 2.0, <TEX>$6.0{\mu}g/kg$</TEX>, 회수율 80.2-98.4%이었으며 RSD가 0.82-6.40%로 양호한 재현성을 나타내었다. 제랄레논 모니터링 결과, 과자류 중 스낵과자류 66건 중 3건에서 <TEX>$6.02-11.82{\mu}g/kg$</TEX> 검출되었고 비스킷 71건 중 2건에서는 <TEX>$14.78-17.83{\mu}g/kg$</TEX> 검출되었다. 면류, 빵류 및 떡류에서는 제랄레논이 검출되지 않았으며 침출차 14건에서 최고 <TEX>$53.76{\mu}g/kg$</TEX> 검출, 선식 24건 중 16건에서 가장 높은 검출율(66.7%)을 나타내었다. 전분 2건, 시리얼두유 1건에서 제랄레논이 각각 5.55-8.56, <TEX>$10.26{\mu}g/kg$</TEX> 검출되었다. 제랄레논 모니터링 결과는 기준이 설정되어 있는 유럽연합(곡류분말: <TEX>$75{\mu}g/kg$</TEX>, 빵, 비스킷, 스낵, 아침식사대용 시리얼류: <TEX>$50{\mu}g/kg$</TEX>, 영아 및 유아용 시리얼류: <TEX>$20{\mu}g/kg$</TEX>) 기준이하의 수준이었으며 국내외 연구보고와 비교한 결과 낮거나 비슷한 수준으로 검토되었다. 연구결과 곡류가공품에 대한 제랄레논 오염수준은 높지 않았으나 지구 온난화로 기후변화에 민감한 곰팡이독소와 같은 자연독소의 발생 증가가 우려되므로 선제적으로 대응하는 안전관리가 요구된다. Zearalenone (ZEA) is an estrogenic mycotoxin mainly produced by Fusarium graminerum, a species which colonizes a wide variety of cereals, including wheat, barley and processed products. A survey of ZEA contamination was conducted on 141 dried confectioneries, 59 breads and rice cakes, 135 noodles and 101 other products, for a total of 432 commercial samples. Samples were analyzed by high performance liquid chromatography with fluorescence detection (HPLC-FLD) after immunoaffinity clean-up and was confirmed by liquid chromatography tandem mass spectrometry (LCMS/MS). The limits of detection and quantification were 2.0 and <TEX>$6.0{\mu}g/kg$</TEX>, respectively. The recovery ranged from 80.2% to 98.4% in the cereal based product. ZEA was detected in 38 samples (8.8% incidence), including 3 snack, 2 biscuit and 33 other cereal products. The ZEA contamination levels were in the range of <TEX>$5.38-53.76{\mu}g/kg$</TEX>. Finally, LC-MS/MS analysis of the contaminated samples was conducted to confirm the detected ZEA, and all 38 samples showing ZEA by HPLC-FLD were confirmed by LC-MS/MS.

HPLC-FLD methods to quantify chloroaluminum phthalocyanine in nanoparticles, plasma and tissue: application in pharmacokinetic and biodistribution studies

Analytical and bioanalytical methods of high-performance liquid chromatography with fluorescence detection (HPLC-FLD) were developed and validated for the determination of chloroaluminum phthalocyanine in different formulations of polymeric nanocapsules, plasma and livers of mice. Plasma and homogenized liver samples were extracted with ethyl acetate, and zinc phthalocyanine was used as internal standard. The results indicated that the methods were linear and selective for all matrices studied. Analysis of accuracy and precision showed adequate values, with variations lower than 10% in biological samples and lower than 2% in analytical samples. The recoveries were as high as 96% and 99% in the plasma and livers, respectively. The quantification limit of the analytical method was 1.12 ng/ml, and the limits of quantification of the bioanalytical method were 15 ng/ml and 75 ng/g for plasma and liver samples, respectively. The bioanalytical method developed was sensitive in the ranges of 15–100 ng/ml in plasma and 75–500 ng/g in liver samples and was applied to studies of biodistribution and pharmacokinetics of AlClPc.

An evaluation of analytical quality for selected PAH measurements in a fuel-contaminated soil

The measurements of polycyclic aromatic hydrocarbons (PAHs) in soil require optimized analytical methods that assess reliable mass fraction results. This is particularly important for analysing very complex matrix such as contaminated soils with crude fuels. The main objectives of this work were focused to minimize analytical effort and assess result reliability in analysis of PAH by high-performance liquid chromatography with fluorescence detection (HPLC/FD). First, analysis of soil samples with/without fuel contamination was well established by sonication (US) and pressurized fluid extraction (ASE) using minimal amount of sample and minimal treatment of sample. On the other hand, an extensive study with spiked and field soil samples was performed by checking proportional and constant bias for analytical validation. The major components for estimating uncertainty contributions were evaluated on the basis of intermediate precision with two fuel matrix, PAH mass fraction and dates of analyses.

Occurrence of Ochratoxin A in Grain and Manufactured Food Products in China Detected by HPLC with Fluorescence Detection and Confirmed by LC–ESI–MS/MS

A total of 110 commercially available samples of manufactured food products including bread, oat, barley, maize, corn, wheat, grape, soluble coffee, soya bean, red wine, and baby food were randomly collected in the northeast of China during the first six months of 2010. Samples were analyzed for the presence of ochratoxin A (OTA) using immunoaffinity column (IAC) clean-up and high-performance liquid chromatography with fluorescence detection (HPLC-FD) and confirmed with LC-ESI-MS/MS. The range of average OTA recoveries was 78.3-103.3% at three spiked levels. The relative standard deviations (RSDs) of recoveries range of 2.1-4.3%. OTA were detected in 13 samples, which were below the maximum allowable limit established by the European Community. The results of this study suggest that those manufactured food products consumed in China present no risk by human exposure to OTA through their consumption.

Clinical significance of simultaneous determination of serum tryptophan and tyrosine in patients with lung cancer

To explore the clinical significance of serum tyrosine (Tyr) and tryptophan (Trp) in patients with lung cancer, we used a simple and efficient method of high-performance liquid chromatography with fluorescence detection (HPLC-FD) that simultaneously measured serum Trp and Tyr contents. The concentrations of Tyr and Trp were measured simultaneously by HPLC-FD in the sera of 80 patients with lung cancer and 120 healthy controls. Trp concentrations were significantly lower in patients with lung cancer than in healthy controls (39.26±5.44 vs. 49.93±5.43 µmol/l, respectively; P<0.01), whereas in Tyr concentrations there were no differences with healthy controls (65.38±7.94 vs.66.40±8.55 µmol/l, respectively; P>0.05). In addition, patients in the adenocarcinoma group had significantly lower Trp and Tyr concentrations than those in squamous cell carcinoma group. There was no difference between the early stage and advanced stage of lung cancer. Determination of serum Trp and Tyr concentrations can be employed to assist the diagnosis of the histotypes of lung cancer and tumor stage. Tyr and Trp as indexes on the lung cancer diagnostic sensitivity, specificity were 54.9, 62.9% and 82.4, 92.1%, Trp is an important and special index for lung cancer diagnosis of which the specificity of diagnosis of lung cancer is more than 92%.

Preparation and evaluation of superparamagnetic surface molecularly imprinted polymer nanoparticles for selective extraction of bisphenol A in packed food

Molecularly imprinted polymer (MIP) coated Fe3O4 nanoparticles (Fe3O4@MIP) were synthesized by atom transfer radical polymerization (ATRP) and used as highly selective magnetic solid-phase extraction (MSPE) sorbents for trace bisphenol A (BPA) from packed food. The morphological and polymeric characteristics of the Fe3O4@MIP were characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. In this work, competitive recognition compounds (4-n-octylphenol and bisphenol A diglycidyl ether) exhibited lower binding capability to the Fe3O4@MIP than BPA. A high performance liquid chromatography with fluorescence detection (HPLC-FLD) method was developed for the determination of BPA in canned orange and milk samples. The main factors influencing the extraction efficiency, including high specificity, the amount of surfactant, the shaking time and the desorption ability of complex food matrices were investigated and optimized. Various parameters such as the pH of thesample, the amount of Fe3O4@MIP sorbent, the extraction time, and the desorption conditions were optimized. Notably, the extraction can be carried out quickly, and the extraction time for BPA onto Fe3O4@MIP sorbents can be clearly shortened to 5 min. Good linearities (r2 > 0.9965) for all calibration curves were obtained, and the limit of detection (LOD) for BPA was 0.1 and 0.3 ng mL−1 in canned orange and milk samples, respectively. To the best of our knowledge, this is the first time that surface molecularly imprinted polymer nanoparticles have been used for the pretreatment of packed food.

Development and optimisation of a dopant assisted liquid chromatographic-atmospheric pressure photo ionisation-tandem mass spectrometric method for the determination of 15 + 1 EU priority PAHs in edible oils

European food legislation defines a set of 16 polycyclic aromatic hydrocarbons (PAHs) as of high concern for human health. The EU set contains structurally very similar PAHs with ring numbers between 4 and 6, and so raises some separation aspects and problems, which were not experienced with traditionally analysed PAHs. Many of the currently applied gas chromatographic mass spectrometric (GC–MS) methods suffer from separation problems, while high performance liquid chromatography with fluorescence detection (HPLC-FLD) is neither capable of detecting the whole set of EU priority PAHs nor does it (compared to GC–MS) allow structural identification. In addition HPLC-FLD shows limitations with difficult matrices due to interferences. The aim of this paper is to fill this gap by describing a liquid chromatographic dopant assisted atmospheric pressure photo ionisation tandem mass spectrometric (LC-DA-APPI-MS/MS) method for the determination of 15+1 EU priority PAHs in edible oil, which complies with the requirements set by European food legislation. Measurements were performed in positive ion mode. Anisole at a flow rate of 30μl/min was used as dopant. Sample preparation was performed offline by donor–acceptor complex chromatography (DACC). Compared to HPLC-FLD methods the presented method enables the determination of all 15+1 EU priority PAHs at the low μg/kg concentration range including less fluorescence active compounds like benzo[j]fluoranthene and indeno[1,2,3-cd]pyrene. By analysing four reference materials it could be demonstrated that this method provides accurate results and is sufficiently sensitive for food control purposes. Statistically significant differences between the reference values and the measured analyte contents were not found. The method performs well also for very complex samples. Repeatability relative standard deviations (RSDr) of the determination of the target PAHs in olive oil were for most analytes below 5%. The limit of detection (LOD) of the method met the requirement set by EU legislation (0.3μg/kg).

Characterization of paralytic shellfish toxins in seawater and sardines (Sardina pilchardus) during blooms of Gymnodinium catenatum

The re-emergence of Gymnodinum catenatum blooms after a 10 year hiatus of absence initiated the present investigation. This study aims to evaluate the exposure of small pelagic fishes to paralytic shellfish toxins (PST) during blooms of G. catenatum. Sardines (Sardina pilchardus) were selected as a representative fish species. In order to assess toxin availability to fish, both intracellular PSTs (toxin retained within the algal cells) and extracellular PSTs (toxin found in seawater outside algal cells) were quantified, as well as toxin levels within three fish tissue matrices (viscera, muscle and brain). During the study period, the highest cell densities of G. catenatum reached 2.5 × 104 cells l−1 and intracellular PST levels ranged from 3.4 to 398 ng STXeq l−1 as detected via an enzyme linked immunosorbent assay (ELISA). Measurable extracellular PSTs were also detected in seawater (0.2–1.1 μg STXeq l−1) for the first time in Atlantic waters. The PST profile in G. catenatum was determined via high performance liquid chromatography with fluorescence detection (HPLC-FLD) and consisted mostly of sulfocarbamoyl (C1+2, B1) and decarbamoyl (dcSTX, dcGTX2+3, dcNEO) toxins. The observed profile was similar to that reported previously in G. catenatum blooms in this region before the 10-year hiatus. Sardines, planktivorous fish that ingest a large number of phytoplankton cells, were found to contain PSTs in the viscera, reaching a maximum of 531 μg STXeq kg−1. PSTs were not detected in corresponding muscle or brain tissues. The PST profile characterized in sardine samples consisted of the same sulfocarbamoyl and decarbamoyl toxins found in the algal prey with minor differences in relative abundance of each toxin. Overall, the data suggest that significant biotransformation of PSTs does not occur in sardines. Therefore, planktivorous fish may be a good tracer for the occurrence of offshore G. catenatum blooms and the associated PSTs produced by these algae.

Rapid resolution liquid chromatography–mass spectrometry and high-performance liquid chromatography-fluorescence detection for metabolism and pharmacokinetic studies of ergosta-4,6,8(14),22-tetraen-3-one

Ergosta-4,6,8(14),22-tetraen-3-one (ergone) from many medicinal plants has been demonstrated to possess a variety of pharmacological activities in vivo and in vitro, including cytotoxic, diuretic and immunosuppressive activity. Metabolism and pharmacokinetic studies on rat were conducted for ergone. Rapid resolution liquid chromatography with atmospheric pressure chemical ionization tandem multi-stage mass spectrometry (RRLC-APCI-MS n) and high-performance liquid chromatography with fluorescence detection (HPLC-FLD) methods were applied for the identification and quantification of ergone and its metabolite from rat plasma, faeces and urine. A metabolite was identified by RRLC-DAD-APCI-MS n: 22,23-epoxy-ergosta-4,6,8(14)-triaen-3-one (epoxyergone). The concentrations of the analyte with its metabolites were determined by HPLC-FLD at excitation wavelength of 370 nm and emission wavelength of 485 nm. The samples were deproteinized with methanol after addition of camptothecin as internal standard (IS). The analysis was performed on a Diamonsil C18 column (150 mm × 4.6 mm × 5 μm) with a mobile phase gradient consisting of methanol and water at a flow rate of 1 mL min −1. The assay was linear over the concentration range of 42–1500, 36–7500 and 42–1500 ng mL −1 for plasma, faecal homogenate and urine respectively. The absolute recoveries were found to be 97.0 ± 1.2%, 98.1 ± 0.7% and 96.6 ± 1.8% for plasma, faecal homogenate and urine respectively. The intra-day and inter-day relative standard deviations (RSD) were less than 10%. The previous HPLC–MS/MS method is not affordable for most laboratories because of the specialty requirement and high equipment cost. However, the HPLC-FLD method is economic and operating simply for quantitative determination of ergone and its metabolite in rat plasma, faeces and urine. In addition, liquid chromatography coupled with ion trap multi-stage mass spectrometry is becoming a useful technique for ergone metabolite identification.