Olive Oil as a Transport Medium for Bioactive Molecules of Plants?-An In Situ Study.

(1) Caries and erosions still remain a challenge for preventive dentistry. Certain plant extracts have shown beneficial effects in preventive dentistry. The aim of this study was to evaluate the antibacterial, anti-adherent and erosion-protective properties of ellagic acid (EA) as a polyphenolic agent. The combination with olive oil was investigated additionally to verify a possible improved bioactive effect of EA. (2) An in situ study was carried out with six subjects. Individual splints were prepared with bovine enamel specimens. The splints were worn for 1 min (pellicle formation time). Thereafter, 10 min rinses were performed with EA in water/in oil. Bacterial adherence was evaluated by fluorescence microscopy (DAPI, ConA, BacLight) after an 8 h oral exposition time. Additionally, the splints were worn for 30 min to quantify demineralization processes. The ultrastructure of the pellicle was investigated after an oral exposure time of 2 h under a transmission electron microscope. Statistical analysis was performed by Kruskal-Wallis tests, Mann-Whitney U tests and Bonferroni-Holm correction. (3) Rinsing with EA led to a significant reduction of adherent vital and dead bacteria. The combination with olive oil did not improve these outcomes. The assessment of glucan structures after rinsing with EA in water showed significant effects. Significant differences were observed for both rinses in calcium release at pH 3.0. After rinsing with EA in oil, significantly less calcium was released compared to rinsing with EA in water (pH = 3.0). (4) Olive oil is not suitable as a transport medium for lipophilic polyphenols. EA has anti-adherent and antibacterial properties in situ. EA also shows erosion-protective effects, which can be enhanced in combination with olive oil depending on the pH value. Ellagic acid has a neutral pH and could be an opportunity in the treatment of specific patient groups (xerostomia or mucositis).

Barbecue conditions affect contents of oxygenated and non-oxygenated polycyclic aromatic hydrocarbons in meat and non-meat patties.

The contents of eight oxygenated polycyclic aromatic hydrocarbons (OPAHs; anthracene-9,10-dione, benzo[a]anthracene-7,12-dione, 11H-benzo[b]fluorene-11-one, 6H-benzo[cd]pyren-6-one, 7H-benzo[de]anthracene-7-one, 9,10-dihydro-8H-benzo[a]pyren-7-one, fluoren-9-one, and naphthacene-5,12-dione) and six PAHs (anthracene, fluorene, and PAH4) were investigated in barbecued meat and non-meat patties. The patties were prepared with ten setups (six replicates, each) of barbecue conditions defined by grill type, grate height, heating medium, and barbecue time. The highest median contents were observed with a disposable grill (OPAHs: 46.3 µg/kg; PAHs: 40.7 µg/kg) and a charcoal grill (OPAHs: 29.6 µg/kg; PAHs: 23.3 µg/kg). Fluoren-9-one and anthracene-9,10-dione were the dominant compounds within OPAHs, but also the four toxicologically most relevant OPAHs were detected with a total up to 11.8 µg/kg. Pairs of OPAHs and corresponding PAHs did not show strong correlations, as individual OPAHs and PAHs were affected differently by the barbecue conditions. No suitable markers for OPAH prediction could be found. We recommend to include OPAHs in future PAH investigations.

Simultaneous Mass Spectrometric Detection of Proteins of Ten Oilseed Species in Meat Products.

Food fraud is a common issue in the modern food industry. The undeclared use of foreign proteins in meat products is a major concern in this context. Oilseeds are ideal for this purpose due to their high protein content and since huge amounts of oil meal are obtained as a by-product of oil production. Therefore, a UHPLC-MS/MS method was developed for the simultaneous detection of chia, coconut, flaxseed, hemp, peanut, pumpkin, rapeseed, sesame, soy, and sunflower proteins in meat products. Potential tryptic peptide markers were identified by high-resolution mass spectrometry. The final twenty peptide markers selected, which are specific for one of the ten species targeted, were each measured by multiple reaction monitoring. To the best of our knowledge, twelve new heat-stable marker peptides for chia, coconut, flaxseed, pumpkin, rapeseed, sesame and sunflower have not been reported previously. Emulsion-type sausages with 0.01, 0.25, 0.50, 0.75 and 1.00% protein addition by each oilseed species were produced for matrix calibration. No false-positive results were recorded. In the quantification of the ten oilseed species, 466 of 480 measuring data points of the recovery rate in unknown sausages (0.15 and 0.85% protein addition by each oilseed species) were in the accepted range of 80-120%.

Cornflower Honey as a Model for Authentication of Unifloral Honey Using Classical Methods Combined with Plant-Based Marker Substances Such as Lumichrome.

According to legislation, unifloral honeys are characterized by their organoleptic, physicochemical, and microscopic properties. Melissopalynology is the established method for identifying the pollen taken up with the floral nectar by forager bees and is used for authentication of the nectar sources in honey. For cornflower honey (Centaurea cyanus), the pollen input does not correlate with the nectar input, because the nectar is produced both in floral and in extrafloral nectaries. The well-known cornflower marker lumichrome has now also been detected in the extrafloral nectar. Therefore, lumichrome is a suitable marker substance for cornflower honey. Four different methods for the sole analysis of lumichrome in honey were validated and compared. Studies over nine years have shown that unifloral cornflower honey should contain approximately 35 mg/kg lumichrome. For a further differentiated cornflower honey specific verification, other nonvolatile compounds like 7-carboxylumichrome and volatiles, such as 3,4-dihydro-3-oxoedulan I and 3,4-dihydro-3-oxoedulan II, should be analyzed. This enables a more specific accuracy for the classification of unifloral cornflower honey.

A sensitive GC-HRMS method for the simultaneous determination of parent and oxygenated polycyclic aromatic hydrocarbons in barbecued meat and meat substitutes.

A sensitive GC-HRMS method was developed to analyze six polycyclic aromatic hydrocarbons (PAH; anthracene, benzo[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, chrysene, and fluorene) and eight oxygenated PAHs (OPAH; anthracene-9,10-dione, benzo[a]anthracene-7,12-dione, 7H-benz[de]anthracene-7-one, 11H-benzo[b]fluorene-11-one, 6H-benzo[cd]pyren-6-one, 9,10-dihydro-8H-benzo[a]pyren-7-one, fluoren-9-one, and naphthacene-5,12-dione) in barbecued meat and meat substitutes. After optimization of the conditions of the sample preparation, consisting of accelerated solvent extraction (ASE) and solid-phase extraction (SPE), high recoveries (PAH 72-109%; OPAH 74-106%) were obtained. The linear regression of the matrix calibration resulted in high correlation coefficients (0.959-0.999). For the first time, reasonably low limits of detection (PAH 0.03-0.17 µg/kg; OPAH 0.04-0.43 µg/kg) were achieved, allowing the analysis of samples barbecued under practical relevant conditions. In charcoal grilled samples, the sum content of the seven detected OPAHs (5.7-62.4 µg/kg) was higher than the sum content of the six PAHs (1.4-36.7 µg/kg). However, 9,10-dihydro-8H-benzo[a]pyren-7-one was not detected in these samples.

Preventive Applications of Polyphenols in Dentistry-A Review.

Polyphenols are natural substances that have been shown to provide various health benefits. Antioxidant, anti-inflammatory, and anti-carcinogenic effects have been described. At the same time, they inhibit the actions of bacteria, viruses, and fungi. Thus, studies have also examined their effects within the oral cavity. This review provides an overview on the different polyphenols, and their structure and interactions with the tooth surface and the pellicle. In particular, the effects of various tea polyphenols on bioadhesion and erosion have been reviewed. The current research confirms that polyphenols can reduce the growth of cariogenic bacteria. Furthermore, they can decrease the adherence of bacteria to the tooth surface and improve the erosion-protective properties of the acquired enamel pellicle. Tea polyphenols, especially, have the potential to contribute to an oral health-related diet. However, in vitro studies have mainly been conducted. In situ studies and clinical studies need to be extended and supplemented in order to significantly contribute to additive prevention measures in caries prophylaxis.

A UHPLC-MS/MS Method for the Detection of Meat Substitution by Nine Legume Species in Emulsion-Type Sausages.

Meat substitution by legume proteins in various types of meat products is a common practice. A reliable detection and quantification of these additives is required to control food specifications, especially regarding food fraud. Consequently, a UHPLC-MS/MS method for the simultaneous detection of alfalfa (Medicago sativa), broad bean (Vicia faba), chickpea (Cicer arietinum), lentil (Lens culinaris), lupine (Lupinus albus and Lupinus angustifolius), pea (Pisum sativum), peanut (Arachis hypogaea), and soy (Glycine max) proteins in meat products was developed. After protein extraction and tryptic digestion, three marker peptides for each legume species were measured by multiple reaction monitoring (MRM) using an optimized extraction protocol. To the best of our knowledge, the marker peptides for alfalfa, broad bean, chickpea, and lentil have not been reported previously. Emulsion-type sausages with 0.1, 0.4, 0.7, 1.0, 1.3, 1.6, 1.9, 2.2, and 2.5% meat substitution by each legume species, representing the concentration range between inadvertently transferred cross-contaminations and the conscious use for meat substitution, were produced for matrix calibration. No false-positive results were recorded in blank samples. In the quantification of alfalfa, broad bean, chickpea, lentil, pea, peanut, and soy, 673 of 756 measuring data of the recovery rate in unknown sausages were in the accepted range of 80-120%.

Differentiation of Honeydew Honeys from Blossom Honeys and According to Their Botanical Origin by Electrical Conductivity and Phenolic and Sugar Spectra.

Honeydew honey, due to its higher antibacterial and antioxidant activity in comparison to blossom honeys, is in high demand and of interest to consumers. Although a differentiation of blossom honeys from honeydew honeys by way of electrical conductivity is given in many cases, criteria for a differentiation of individual honeydew honeys, such as spruce, fir, and pine, however did not exist. For this reason, 93 authentic honeydew honeys and 63 non-honeydew honeys [35 blossom and 28 nectar-honeydew (mixed)] from 13 different botanical origins were collected within the framework of the current study, and their electrical conductivity and phenolic and sugar profiles were investigated. Results showed that the higher electrical conductivity (≥0.80 mS/cm), the higher protocatechuic acid content (≥3.5 mg/kg), and the higher percentage of the oligosaccharide content (≥120 mg/g) were suitable parameters for the differentiation of authentic coniferous honeydew honeys from non-honeydew honeys; a differentiation. A differentiation of the spruce, fir, and pine honeydew honeys however could not be reached. Through the analysis of 32 carbohydrates (2 mono-, 7 di-, 10 tri-, and 13 higher oligosaccharides) in only one run by high-performance liquid chromatography equipped with an evaporative light scattering detector, marker substances can now be utilized for the classification of individual honeydew honeys. Sugar marker compounds such as α,α-trehalose, melezitose, theanderose, nystose, or maltotetraose in honeydew honeys in combination with chemometrics highlighted the good capability of sugar profiles to discriminate the honeydew honeys both from the non-honeydew honeys and from each other. All in all, a 96.75% correct classification of all studied 156 honey samples was achieved by sugar marker compounds.

Effect of fragaria vesca, hamamelis and tormentil on the initial bacterial colonization in situ.

OBJECTIVE: The presentin situ study aims to examine the influence of the polyphenolic tea drugs fragaria vesca, hamamelis and tormentil on the initial oral bioadhesion. DESIGN: Initial biofilm formation was performed on bovine enamel slabs which were carried intraorally by 12 subjects. After 1 min of intraoral pellicle formation, the subjects rinsed with fragaria vesca, tormentil (0.8 mg/8 mL) and hamamelis (0.2 mg/8 mL) for 10 min. Tap water served as negative control, 0.2 % CHX as positive control. The investigations took place on different days (wash-out: 2 days). Afterwards, fluorescence microscopy has been performed per test solution (n = 5) and per subject (n = 12) to visualize bacterial adhesion and glucan formation (8 h oral exposition) with DAPI, ConA and BacLight. Additionally, TEM was used to visualize the pellicle ultrastructure and expectorate samples. Statistical evaluation was carried out using the Kruskal-Wallis- (p < 0.5), Mann-Whitney U test (p < 0.5) and Bonferroni-Holm-correction (p < 0.1). RESULTS: Rinsing with the polyphenolic tea extracts reduced significantly initial bacterial colonization (DAPI) compared to the negative control. There was no significant difference betweenfragaria vesca, hamamelis and tormentil. All solutions showed a reducing effect on the glucan formation. No significant difference was observed between fragaria vesca and CHX. Considerable alterations of the pellicle's ultrastructure manifested by an increase in thickness and electron density resulted from rinsing with the three polyphenolic aqueous extracts. CONCLUSIONS: Fragaria vesca, hamamelis and tormentil significantly reduce initial bioadhesion and glucan formation in situ and are therefore recommended as adjuvant antibacterial oral therapeutics.

Influence of Smoking and Barbecuing on the Contents of Anthraquinone (ATQ) and Polycyclic Aromatic Hydrocarbons (PAHs) in Frankfurter-Type Sausages.

The contents of anthraquinone (ATQ) and polycyclic aromatic hydrocarbons (anthracene (ANT) and PAH4) in smoked Frankfurter-style sausages were investigated depending on various smoking conditions. During smoking, the smoke generator, the smoking duration, the type of wood, and some more plant-specific parameters were tested. The sausages were also barbecued on a charcoal grill. The lowest mean contents of all analytes were observed when friction smoke was used (ATQ < limit of quantification (LOQ); ANT < LOQ; PAH4 < limit of detection (LOD)) and the highest when the settings of ventilations flaps were changed (ANT 36.3 µg/kg; PAH4 2.2 µg/kg) or at an intensive smoke density (ATQ 3.2 µg/kg). The contents increased with the smoking time, but irregularities were detected after 10 min. The use of different types of wood had no influence on the ATQ content but affected the PAH content. In barbecued samples, ATQ and ANT contents were detected at the level of friction smoke and maximum PAH4 contents were found above the exposure during smoking. Due to the varying influence of the smoking parameters on the two analytes, there was no direct correlation between the contents of ATQ and ANT in all smoking experiments.

Stability of pyrrolizidine alkaloids from Senecio vernalis in grass silage under different ensilage conditions.

BACKGROUND: This study evaluated the degradation of pyrrolizidine alkaloids (PAs) from eastern groundsel (Senecio vernalis) in grass silage prepared with different inoculants. Silages were produced from ryegrass with 230 g kg-1 dry matter (DM) content and mixed with eastern groundsel (9:1; w/w fresh matter basis) containing 5.5 g kg-1 DM PA. Treatments were: CON (untreated control), LP (3.0 × 105 cfu g-1 Lactobacillus plantarum DSMZ 8862/8866) or LBLC (7.3 × 104 cfu g-1 Lactobacillus buchneri LN40177 / Lactobacillus casei LC32909), and each of the treatments in combination with 30 g kg-1 molasses. Silages were prepared in glass jars and opened after 3, 10, and 90 days. Fermentation characteristics were determined and the PAs analyzed. RESULTS: Although the levels of fermentation acids differed between treatments, results indicated good quality of all silages during 90 days. Significant time (P < 0.001) and treatment (P < 0.001) effects were observed for PAs. Concentrations of senecionine and seneciphylline decreased with molasses, declined over time, and were negatively correlated with lactic, propionic, and butyric acid, or with lactic and butyric acid in case of seneciphylline. In all silages, seneciphylline and senecionine N-oxides were undetectable after 3 days, whereas senkirkine, the most abundant PA, remained stable. CONCLUSIONS: Silage prepared from grass contaminated with eastern groundsel still contained high PA levels, and was hence a potential health hazard. Molasses supplementation reduced concentrations of senecionine and seneciphylline, while the bacterial inoculants had no effect. Other potentially toxic PA metabolites were not analyzed in the present study and further research is needed. © 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Simultaneous determination of pesticides, mycotoxins, and metabolites as well as other contaminants in cereals by LC-LC-MS/MS.

A 2D LC-MS/MS method for the simultaneous determination of 350 pesticides, 16 mycotoxins as well as the growth regulators Chlormequat and Mepiquat was developed. The method is applicable to cereals and products thereof. Attention should be paid to the simultaneous analysis of the cereal-relevant mycotoxins aflatoxin B1, B2, G1 and G2, ochratoxin A, deoxynivalenol and zearalenone. Moreover, the tropane alkaloids atropine/scopolamine could be integrated into the final method. The samples were extracted with a mixture of acetonitrile/water (80:20), diluted with acetonitrile and injected into an LC-LC-MS/MS system. There were no further manual clean-up steps. The automatic online clean-up took place during the HILIC-separation in the first dimension (YMC-Pack Diol; 2.1 × 100 mm; 5 µm, 120 Å). Here, polar matrix compounds were retained, while the majority of the analyte scope eluted in a fraction at the beginning of the analytical run. This fraction was transferred to the second dimension by a packed loop interface (Agilent Zorbax SB-C8; 4.6 × 12.5 mm; 5 µm; 80 Å). On the second column (Phenomenex Synergi Fusion RP C18; 2 × 100 mm; 2.5 µm; 100 Å), the majority of the scope was separated by a typical RP-gradient. Only some of the polar pesticides could not be transferred to the second column. They eluted directly after the transfer step from the HILIC-column to the MS/MS. The final method was sensitive enough to meet all the regulated maximum levels for pesticides in cereals according to EU Regulation 396/2005 and those for contaminants according to EU Regulation 1881/2006. Above all, the method was so robust and accurate that nearly 90% of the pesticides and all the tested mycotoxins, growth regulators and tropane alkaloids fulfilled the validation criteria of the SANTE guideline document, although the demanding criteria are only applicable to pesticides. For the verification, eight proficiency tests were passed successfully: three for the pesticide analysis, three for the mycotoxin analysis, and two for the analysis of the tropane alkaloids. In addition to the already mentioned contaminants, the six most important ergot alkaloids (e.g. ergotamine/ergotaminine) and two modified mycotoxins (deoxynivalenol-3-glucoside and zearalenone-sulfate, also known as masked mycotoxins) were detected during the routine analysis of rye and corn samples.

Ultra turrax® tube drive for the extraction of pesticides from egg and milk samples.

The Ultra turrax® tube drive, already successfully applied for the extraction of plant materials, has also proved to be suitable for the analysis of pesticides in eggs and milk. In comparison to the matrix solid-phase dispersion (MSPD), the extraction is less time-consuming at excellent extraction efficiency. Further advantages are the flexibility of the extraction conditions with respect to the pH value and water activity. So, even strongly acidic pesticides such as phenoxy carboxylic acids can be extracted. Eighty-nine GC-amenable and 75 LC-amenable pesticides, which had been detected successfully in whole chicken eggs following MSPD extraction and further processing according to Hildmann et al., could also be analyzed with the modified method. In addition, the analysis spectrum could be expanded by 4 GC- and 37 LC-amenable substances. Of the 208 pesticides tested, 205 substances could be detected in whole chicken eggs. Similar excellent results were achieved for the milk matrix. Furthermore, the modified extraction method allows a determination of the fat content from the same analysis approach.

Identification of New Compounds from Sage Flowers (Salvia officinalis L.) as Markers for Quality Control and the Influence of the Manufacturing Technology on the Chemical Composition and Antibacterial Activity of Sage Flower Extracts.

Parts of Salvia species such as its flowers and leaves are currently used as a culinary herb and for some medicinal applications. To distinguish the different sage extracts it is necessary to analyze their individual chemical compositions. Their characteristic compounds might be established as markers to differentiate between sage flowers and leaf extracts or to determine the manufacturing technology and storage conditions. Tri-p-coumaroylspermidine can be detected only in flowers and has been described here for Salvia and Lavandula species for the first time. Markers for oxidation processes are the novel compounds salviquinone A and B, which were generated from carnosol by exposure to oxygen. Caffeic acid ethyl ester was established as an indirect marker for the usage of ethanol as extraction solvent. The compounds were identified by LC-QTOF-HRESIMS, LC-MS, NMR, IR, and single-crystal X-ray diffraction after isolation by semipreparative HPLC. Furthermore, sage flower resin showed interesting antibacterial in vitro activities against Gram-positive and Gram-negative bacteria.

The chemical composition of the pharmacologically active Thymus species, its antibacterial activity against Streptococcus mutans and the antiadherent effects of T. vulgaris on the bacterial colonization of the in situ pellicle.

The pharmacological active genus Thymus L. comprises over 200 species. Besides its traditional pharmacological use, thyme may reduce the risk of caries disease, however, there is very little respective literature. The pharmacological effects can be attributed to the secondary plant metabolites. The composition of the essential oil and the polyphenols is important for the evaluation of the pharmacological activity. Nevertheless, there are no studies regarding a comparative analysis of the different pharmacological thyme species. In the present study, four different pharmacology Thymus species were cultivated under comparable conditions, and the volatile compounds as well as the polyphenols were characterized. In addition, the in vitro antibacterial activity against S. mutans, one of the primary cariogenic bacterial species, as well as of the essential oil and of the polyphenols were investigated. Furthermore, the bacterial viability and its effect on the initial bacterial adhesion under oral conditions were evaluated in situ for the essential oil and the polyphenols. By GC-MS, 69 volatile compounds, and by LC-DAD-MS/MS, 46 polyphenols could be identified. The comprehensive examination of the essential oils and the polyphenols revealed that the main compounds were equal. However, the yield of the essential oil and the polyphenol content differed clearly. The essential oils of the four investigated Thymus species exhibited an antibacterial activity against S. mutans in vitro, in contrast to the polyphenols of T. vulgaris. Rinsing with polyphenol-rich infusions reduced the initial bacterial colonization while the essential oil inhibited the bacterial growth on dental enamel in situ.

Fluorescent Pteridine Derivatives as New Markers for the Characterization of Genuine Monofloral New Zealand Manuka (Leptospermum scoparium) Honey.

New Zealand manuka honey is well-known for its unique antibacterial activity. Due to its high price and limited availability, this honey is often subject to honey fraud. Two pteridine derivatives, 3,6,7-trimethyl-2,4(1H,3H)-pteridinedione and 6,7-dimethyl-2,4(1H,3H)-pteridinedione, have now been identified in New Zealand manuka honey. Their structures were elucidated by LC-QTOF-HRMS, NMR, and single-crystal X-ray diffraction after isolation via semipreparative HPLC. Their marker potential for authentic manuka honey was proved as both substances were detectable in neither the pollen-identical kanuka honey nor the nine other kinds of monofloral New Zealand honey analyzed (clover, forest, kamahi, pohutukawa, rata, rewarewa, tawari, thyme, and vipers bugloss). The fluorescence property of the pteridine derivatives can be used as an easy and fast TLC screening method for the authentication of genuine manuka honey. 6,7-Dimethyl-2,4(1H,3H)-pteridinedione has been described for the first time.

The Polyphenolic Composition of Cistus incanus Herbal Tea and Its Antibacterial and Anti-adherent Activity against Streptococcus mutans.

The Mediterranean plant Cistus incanus is rich in polyphenols and has shown several pharmacological activities, mainly antibacterial effects. Furthermore, in situ studies revealed that a C. incanus infusion reduces the initial bacterial adhesion in the oral cavity due to the polyphenols, an indication that C. incanus might reduce the risk of caries disease. In the present study, the polyphenols from four different commercial C. incanus herbal teas were extracted by standardized accelerated solvent extraction for in vitro tests and by an infusion for in situ tests. Both extracts were characterized qualitatively and quantitatively by high-performance liquid chromatography and only the polyphenol content differed slightly. By means of diode array detection and mass spectrometry, 29 polyphenols, including ellagitannins, flavanols, and glycosylated flavonols, were identified. Thereby, only quantitative but no qualitative differences between the four samples were detected. Furthermore, the in vitro antibacterial activity of the C. incanus accelerated solvent extracts against Streptococcus mutans, one of the primary cariogenic bacterial species, was examined using a live/dead assay (BacLight®). With this approach, C. incanus yielded antibacterial properties. Additional in situ experiments indicated that rinses with a C. incanus infusion reduced the initial bacterial colonization of enamel samples exposed to oral fluids for over eight hours. Furthermore, it was shown by transmission electron microscopy that the application of a C. incanus infusion modifies the ultrastructure of the acquired enamel pellicle, yielding a more electron-dense morphology. It can be assumed that the polyphenols are responsible for the observed effects.

Multi-residue pesticide analysis (gas chromatography-tandem mass spectrometry detection)-Improvement of the quick, easy, cheap, effective, rugged, and safe method for dried fruits and fat-rich cereals-Benefit and limit of a standardized apple purée calibration (screening).

Some steps of the QuEChERS method for the analysis of pesticides with GC-MS/MS in cereals and dried fruits were improved or simplified. For the latter, a mixing vessel with stator-rotor-system proved to be advantageous. The extraction procedure of dried fruits is much easier and safer than the Ultra Turrax and results in excellent validation data at a concentration level of 0.01mg/kg (116 of 118 analytes with recoveries in the range of 70-120%, 117 of 118 analytes with RSD <20%). After qualifying problematic lipophilic pesticides in fat-rich cereals (fat content >7%), predominantly organochlorines showed recoveries of <70% in quantification when the standard QuEChERS method with water was used. A second extraction was carried out analogous to the QuEChERS method, however, without the addition of water. With this simple modification, the problematic lipophilic pesticides, which had been strongly affected by the fat content of the commodities, could be determined with recoveries above 70% even at a concentration level of 0.01mg/kg. Moreover, a GC-MS/MS screening method for 120 pesticides at a concentration level of 0.01mg/kg was established by employing analyte protectants (ethylglycerol, gulonolactone, and sorbitol). The use of only one standardized calibration, made of an apple purée extract in combination with analyte protectants, allowed for a qualitative and quantitative analysis of 120 pesticides in different matrix extracts (tomato, red pepper, sour cherries, dried apples, black currant powder, raisins, wheat flour, rolled oats, wheat germ). The analyte protectants leveled the differences in the matrix-induced protection effect of the analyzed extracts over a wide range. The majority of the pesticides were analyzed with good analytical results (recoveries in the range of 70-120% and RSD <20%).

Pesticide residues in chicken eggs - A sample preparation methodology for analysis by gas and liquid chromatography/tandem mass spectrometry.

A sample preparation method was developed for the analysis of chicken eggs to determine 97 GC and 81 LC amenable residues, including organophosphates, organochlorines, pyrethroids, triazoles, carboxyl-containing compounds, and the indicator PCBs. Hereby, considerations were given to the recoveries of the analytes, the method's suitability for routine analysis, and the assessment of the clean-up effect, for which a simple thin layer chromatography was implemented to visualize the most important lipid classes. The procedure consisted of (I) the extraction by matrix solid phase dispersion, and the clean-up by means of (II) small-scale gel permeation chromatography (GPC) and (III) two different solid phase extractions (SPE) for GC and LC amenable analytes, as well as (IV) the quantification using GC-MS/MS and LC-MS/MS. Cyclohexane/ethyl acetate was chosen as extraction solvent due to its suitability for extracting strong non-polar but also more polar analytes. The classical GPC was scaled down to ensure a 50% lower solvent consumption. The comprehensive investigation of conventional and modern zirconium-oxide-coated SPE materials resulted in the selection of octadecyl-modified silica (C18) combined with primary secondary amine using acetonitrile as elution solvent for GC amenable analytes and pure C18 in combination with acidified methanol for LC amenable pesticides. Compared to the currently established EN 1528 method the sample preparation proposed offered a higher sample throughput and a lower solvent consumption. Furthermore, for the first time the clean-up effectiveness of the sample preparation steps was documented as shown by means of thin-layer chromatography. The validation of chicken eggs proved the fulfillment of the quality control criteria for 164 of the 178 analytes tested, mostly at the lowest validated level of 5µg/kg for pesticides and 0.5µg/kg for the single indicator PCBs. However, the analysis of strongly polar analytes was still problematic, which could be attributed to the extraction and the GPC step. Nevertheless, the successful investigation of EU proficiency test materials (EUPT AO 07-09) confirmed the comparability of the results with the currently established sample preparation procedures and demonstrated the potential of the applicability of the presented method to other matrices as exemplified for lean poultry meat and fatty liquid cream.

Differentiation of manuka honey from kanuka honey and from jelly bush honey using HS-SPME-GC/MS and UHPLC-PDA-MS/MS.

In the present study, pollen-identical pure manuka and kanuka honeys and an Australian jelly bush honey were analyzed for the nonvolatiles by UHPLC-PDA-MS/MS and for the volatiles by HS-SPME-GC/MS. A chromatographic profile matchup by means of characteristic marker compounds achieved a clear discrimination between manuka, kanuka, and jelly bush honey. UHPLC-PDA profiles of manuka honey show leptosin, acetyl-2-hydroxy-4-(2-methoxyphenyl)-4-oxobutanate, 3-hydroxy-1-(2-methoxyphenyl)-penta-1,4-dione, kojic acid, 5-methyl-3-furancarboxylic acid, and two unknown compounds as prominent, kanuka honey was characterized by 4-methoxyphenyllactic acid, methyl syringate, p-anisic acid, and lumichrome. 2-Methylbenzofuran, 2'-hydroxyacetophenone, and 2'-methoxyacetophenone were markant volatiles for manuka honey, whereas kanuka honey was characterized by 2,6,6-trimethyl-2-cyclohexene-1,4-dione, phenethyl alcohol, p-anisaldehyde, and an unknown compound in HS-SPME-GC/MS. The jelly bush honey differed from the manuka honey by higher contents of 2-methoxybenzoic acid and an individual unknown substance in the PDA profile and by lower intensities of 2'-methoxyacetophenone, higher concentrations of cis-linalool oxide, and 3,4,5-trimethylphenol in the HS-SPME-GC/MS profile.