Search

In this work, derivatization of ethyl carbamate (EC) with 9-xanthydrol prior to liquid chromatography with fluorimetric detection (HPLC-FLD) was revisited, focusing on refining the reaction conditions and on automation. Perchloric acid was used for sample acidification and a sequence of operations was defined to perform the reaction in the autosampler needle. Chromatographic separation together with automated pre-column derivatization accounted for 18.5 min analytical run. FLD photomultiplier gain was changed in the elution region of analyte to enhance sensitivity. The instrumental detection limit (DL) was 0.52 μg L−1; after suitable sample pretreatment, the proposed procedure was applied for EC determination in liquors, red wines and soy sauces (method DLs: 0.59; 0.96; 0.65 μg L−1, respectively). Recoveries obtained after standard addition were in the range 101–103%, 71–79% and 89–93%, respectively. Standard addition method was used for EC quantification in several samples; the concentrations ranged from not detected up to 40.7 μg L−1 in liquors, 25.9 μg L−1 in wines and 7.18 μg L−1 in soy sauces.

The synthesis of 2-hydroxybenzylidene-4-[(aza, thio)xantenyl]anilines has been carried out via the reaction of 2-hydroxybenzaldehyde, aniline, and (aza, thio)xanthydrol in acetic acid or ethanol medium. Two competing pathways leading the formation of 2-hydroxybenzylidene-4-[(aza, thio)xantenyl]anilines have been revealed by means of chromato-mass spectrometry. The growth-regulating activity of 2-hydroxybenzylidene-4-(5H-benzopyrano[2,3-b]-pyridin-5-yl)aniline towards spring wheat (Gornouralskaya variety) has been studied.

Acrylamide, a “possible carcinogen” compound, has been subjected to analytical method development and evaluation in carbohydrate-rich cookie samples in this research. Cookies with different formula and consequently different acrylamide content were evaluated using microextraction method coupled with gas chromatography-mass spectrometry. Xanthydrol was selected as an efficient derivatization reagent. Important parameters in the extraction step such as the volume of extraction solvent, volume of dispersive solvent, amount of salt, and sample pH were optimized using central composite design. The calibration curve showed good linearity (R2 > 0.998) for acrylamide in the range of 2–500 ng g−1. The limits of detection and quantitation were 0.6 ng g−1 and 1.9 ng g−1, respectively. The relative standard deviation for the six analyses was 9.2%, and relative recoveries of acrylamide in spiked cookie samples were 89–95%. The proposed method demonstrated high recovery, sensitivity, and good enrichment factor for acrylamide determination of cookies with low and high acrylamide content.

Acrylamide is assumed to be a potential carcinogen, and reference values have therefore been implemented in EU legislation. Thus, the food industry needs to reduce the acrylamide content in consumer products to the lowest possible value. In this study, roasted rye was evaluated for its suitability as a coffee substitution product with respect to its acrylamide content. The influence of process modifiers, free asparagine content, storage, and rye type on the final content of acrylamide was investigated. Changes in carbohydrate composition and brightness caused by the roasting process were described. Sample analysis was conducted via GC-MS and HPLC-CAD. Existing methods were adapted to roasted rye as the sample matrix. CaCl2 and asparaginase treatment as well as pH adjustments prior to roasting did not prove to reduce the acrylamide content. A significantly (* p &lt, 0.027) lower free asparagine content in the raw material resulted in a lower formation of acrylamide in the final product. The acrylamide content significantly decreased (**** p &lt, 0.0001) after 3 (1100 &plusmn, 18 &micro, g kg&minus, 1) and 6 (490 &plusmn, 7 &micro, 1) months of long-term storage. Only samples stored for 6 months (490 &plusmn, 1) met the EU acrylamide content requirements (&lt, 500 &micro, 1) for grain-based coffee substitution products.

9-Xanthydrol was introduced as an assisted-extraction-reagent to quantify ethyl carbamate (EC) in wines by heart-cutting multidimensional gas chromatography coupled with mass spectrometry (MDGC-MS). 9-Xanthydrol could help to increase the extraction efficiency, because it could react with ethyl carbamate to form the low-polar product, which facilitated the transfer of ethyl carbamate into organic phase. Then the reaction product was decomposed in high temperature, so ethyl carbamate could be obtained again in injector port. Heart-cutting multidimensional gas chromatography coupled with mass spectrometry was used not only for avoiding 9-xanthydrol interference but also for getting a larger volume injector, higher sensitivity and lower limit of detection. The method was optimized and validated in terms of sample volume, sodium chloride, the acid concentration, the 9-xanthydrol concentration and the reaction time. Good linear relationship (R2 = 0.9998) over the concentration range of 2.00 μg L−1 - 200.00 μg L−1 was obtained. The limit of detection (LOD, 0.02 μg L−1) and quantification (LOQ, 0.10 μg L−1) were lower than previously reported. The RSDs of precision (repeatability and reproducibility) were lower than 8.15%, and the recovery (96.17–99.25%) and accuracy (99.21–110.93%) were validated as well. This methodology was applied to the quantification of ethyl carbamate in several different fermented wines with values ranging from 13.05 to 155.20 μg L−1.

In the present research, a various bread samples were analyzed to determine acrylamide using highly sensitive ultrasonic assisted extraction and microextraction method. Xanthydrol was used in derivatization step and gas chromatography-mass spectrometry (GC-MS) as a powerful instrumentation was implied. Response surface methodology (RSM) based on central composite design (CCD) was applied to optimize the effective factors in microextraction process. The best microextraction efficiency was obtained under optimum conditions. The calibration graph of the proposed method was linear in the range of 10–500 ng g−1 with the correlation coefficient (R2) 0.9982. The relative standard deviations were 5.4% (n = 7). The limit of detection (LOD) was 0.54 ng g−1 and the recovery of these compounds in spiked bread sample was 98%. The increased sensitivity in using the proposed method has been demonstrated. Compared with other methods, UAE-DLLME-GC-MS is an accurate, sensitive, fast and reliable sample-pretreatment method for determining the very low amount of acrylamide in various bread samples.

Rationale Natural stable nitrogen isotope ratios (δ15N values) are frequently used for the determination of provenance and dietary assessment of recent and ancient humans. Although individual δ15N values typically correspond to the dietary δ15N composition, they are also affected by metabolic conditions. Preferred matrices for the mesurement of human δ15N values have been hair, nail or blood. The goal of this study was to validate a novel approach for the assessment of the δ15N values from urinary urea, the principal end-product of human N metabolism. Methods The method, which involves the precipitation of urea from urine using xanthydrol, was validated using fortified urea solutions. Intra- and inter-individual variance of the δ15N values of urinary urea was determined from samples obtained from multiple human subjects. Results Precipitation with xanthydrol did not alter the δ15N values of urea. The mean δ15N value in urinary urea from human subjects from Germany was +4.4 ±0.6 ‰, which corresponds to the estimated dietary composition. It falls below previously reported δ15N values for human tissue and blood samples. Longitudinal analyses over seven days illustrate short-time changes linked to varying protein intake. Discussion Our results indicate that δ15N values can be measured reliably from human urine and that the method is suitable to monitor rapid dietary and metabolic changes of an individual. Our findings further confirm that urinary urea is depleted in 15N compared with human tissue but within the range of the δ15N composition of the diet.

The far-ranging occurrence of acrylamide (AA), a Group 2A carcinogen, in extensively consumed processed foodstuffs has aroused worldwide public health concern, and heightened the need for rapid and reliable detection technologies. Current immunoassays for AA are mainly based on antibodies against mercaptobenzoic acid (MBA) derivatized AA, and thus require a relatively complicated pre-analysis sample derivatization using MBA (heating > 50 °C, time>1 h), which limits the analysis efficiency. In this work, two haptens against xanthyl acrylamide (XAA) were synthesized, and a specific and high-affinity polyclonal antibody against XAA (anti-XAA pAb) was obtained. By virtue of this antibody, a fluorescence immunoassay for quantification of acrylamide with a simple sample derivatization by 9-xanthydrol (ambient temperature, 30 min) was developed via introducing the fluorescent signal of carbon dots (CDs) through the facile inner-filter eff ;ect (IFE) strategy. This fluorescence immunoassay displayed a sensitive and specific response to AA with a detection limit of 0.16 μg/L, which was lower than the legal limit in drinking water (0.5 μg/L) set by WHO. Recovery test and method validation by HPLC-MS/MS demonstrated its good accuracy and reliability, suggesting that this fluorescence immunoassay can be a potentially effective tool for the supervision of AA contamination in foods.

Ethyl carbamate is a group of 2A carcinogen ubiquitously existed in fermented foods. The monitoring of its residues was important for evaluating the potential risk to human beings. Immunoassays with good accuracy and simplicity are great analytical tools for small molecule contaminants. However, it is typically confined in a competitive mode for small molecules with drawback of the sensitivity curbing. In this work, three different phages displayed peptides with capability of identifying the xanthyl ethyl carbamate immunocomplex were isolated from phage library. The binding mechanism of peptides and immunocomplex was studied by computer-assisted simulation. Results indicated that the xanthydrol group of xanthyl ethyl carbamate and the Asn-32 and Asn-92 residues of the antibody light chain were mainly responsible for binding. Simultaneously, a sensitive non-competitive immunoassay for detecting ethyl carbamate in wine samples was developed. The established method exhibited a limit of detection of 5.4ng/mL and a linear range from 8.7ng/mL to 32ng/mL for wine samples. In comparison with the conventional competitive immunoassay, the sensitivity of the proposed non-competitive immunoassay was improved by 17-fold. The results of the immunoassay were validated by a standard ultra-performance liquid chromatography-quadrupole/orbitrap high-resolution mass spectrometry, which illustrated good reliability of the proposed assay.

In order to find innovative protocols to reduce acrylamide (AA), a genotoxin and a probable carcinogen, in foods, several phenolic compounds were considered as additives to a potato derivative. Phenols are obtained from the by-products of the olive production chain. Potato flakes were kneaded with water containing different concentrations of a single phenol: tyrosol (Ty), hydroxytyrosol (HTy), tyrosyl acetate (TyAc), hydroxytyrosyl acetate (HTyAc), caffeic acid and oleuropein. After a cooking step at 175 °C for 4 min, AA was extracted, derivatized with xanthydrol and quantified by GC–MS. The results obtained for Ty, HTy, caffeic acid and oleuropein showed AA reduction ranging from 29 % to 47 %, whereas with TyAc and HTyAc the mitigation effect was noticeably stronger (90 and 75 %). The less polar molecule, TyAc, showed the best inhibition performance. These preliminary results show that phenolic compounds from olive by-products could also be valorized as food starchy additives.

N-Aryl(hetaryl)methylidene-4-[9-(thio)xanthenyl]anilines, N-arylmethylidene-{4-(5H-chromeno[2,3-b]pyridin-5-yl)phenyl}amines, and N-aryl(hetaryl)methyl-4-[9-(thio)xanthenyl]anilines were synthesized via the reaction of imines and amines with xanthydrol, thioxanthydrol, and 1-azaxanthydrol and exhibited antibacterial activity with respect to S. aureus No. 906 and E. coli No. 1257. Six museum and five hospital microorganism strains and three compounds that exhibited earlier high biological activity against three cultures (S. aureus No. 906, E. coli No. 1257, and C. albicans No. 24433) were tested in an expanded study.

A B S T R A C T Background and Objectives: In the production process of foods rich in carbohydrates and some other foods containing precursors of acrylamide formation, there is the possibility of acrylamide creation, which is a mutagen and carcinogen material. This study aims to introduce and optimize a new method for determining acrylamide in potato chips using xanthydrol as a derivative representative with gas chromatography-mass spectrometry. Materials and Methods: Important factors in the derivatization and measurement processes were optimized using the one-factor-at-a-time method. The peak areas were assumed as the GC-MS response to evaluate the extraction efficiency of acrylamide, and optimization for all tests was performed two times. Figures of merit of the proposed method were evaluated. The amount of acrylamide in four potato chips samples, obtained from the market in Tehran city, was determined using the proposed method. Results: The optimum amounts of effective parameters, including derivatization temperature at 25 o C, derivatization time (40 min), xanthydrol volume (40 µL), extracted solvent volume (500 µL) and pH=7 were determined. The figures of merit for the proposed method were at the ideal range. The maximum and minimum amounts of acrylamide in the chip samples were also measured. Conclusions: The performance and reliability of proposed method as a simple, efficient and rapid method for determining acrylamide in potato chip samples were demonstrated.

An innovative, rapid and sensitive non-aqueous reaction system was first established for the determination of acrylamide (AA) by using gas chromatography-mass spectrometry (GC-MS) after derivatization with xanthydrol. Dimethyl sulfoxide (DMSO) was used as an extractant to extract and pre-concentrate AA from food samples before the derivatization reaction. The concentrated AA in DMSO could react with xanthydrol in 1 min at 40 °C under mild reaction conditions, which considerably simplified and stabilized the derivatization reaction process. Under optimal conditions, the method was validated for various food matrices and showed good linearity, precision and trueness. The linear response was in the range of 0.005–4 μg mL−1, with a correlation coefficient (R) of 0.99993. The limit of detection (LOD, S/N = 3) was 0.7 μg kg−1. The relative standard deviation (RSD) ranged from 2.3% to 6.1% (n = 6) at the concentrations of 25.0, 250 and 1000 μg kg−1. The proposed method enabled the reliable analysis of acrylamide in a variety of processed foods in China, including deep fried and baked foods.

Acrylamide has neurotoxicity, carcinogenicity, and genotoxicity in experimental animals and cellular systems. Fried potato is one of the major intake sources of acrylamide in food, and fried onion was reported to contain up to 100 ng/g level of acrylamide. To determine acrylamide concentration in potato and onion stir-fried prior to boiling for simmered dishes such as curry, stew, and Niku-jaga, a typical Japanese meat/potato/onion cuisine, we collected samples stir-fried at homes of volunteers who intended voluntarily to cook these simmered dishes. Acrylamide level was analyzed by GC-MS after the xanthydrol derivatization. Among 53 stir-fried potato samples, median and average values of acrylamide were found to be 2.0 ng/g and 11 ng/g, respectively. Acrylamide levels of 27 samples (51%) were less than limit of detection (LOD) (4 ng/g), and those of 13 samples (25%) were less than limit of quantification (LOQ) (10 ng/g). In cases with less than LOD and less than LOQ of acrylamide levels, one-half of LOD and average of LOD and LOQ were adopted, respectively, to calculate the median and average. This median was markedly lower than those of fried potato (180 ng/g) and potato snacks including potato chips (550 ng/g) reported in monitoring in 2013 fiscal year in Japan. Among 58 stir-fried onion samples, acrylamide level of only one sample (2%) was less than LOD (3 ng/g), and those of 15 samples (26%) were less than LOQ (8 ng/g). The median and average values in the stir-fried onion were 14 ng/g and 36 ng/g, respectively. These values are comparable to those for stir-fried onion reported by Ministry of Agriculture, Forestry and Fisheries, Japan (median 19 ng/g, average 25 ng/g). But the maximum value of stir-fried onion 420 ng/g in the present study is much higher than the reported maximum value (70 ng/g).

Diverse methodologies are available for quantification of acrylamide (AA), a recent known food-borne toxin. However, these methodologies involve complex, lengthy, and expensive procedures. In this work, a simple method based on a recently developed AA derivatization technique using xanthydrol, avoiding any time-consuming cleanup step, was optimized in order to be applied to the determination of AA in fried potatoes. The method entailed the extraction of AA with water and simultaneous defatting with 1,2-dichloroetane, followed by concentration and derivatization reaction with xanthydrol. The xanthyl-acrylamide formed was extracted with ethyl acetate and analyzed by gas chromatography–mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. The optimum conditions of derivatization were achieved by response surface methodology based on central composite design. Time, temperature, and volume of xanthydrol solution showed to be the most influencing variables. Under the established conditions, the limit of detection and quantification were 4 and 10 μg/kg, respectively. Validation of the method was performed with recoveries in the 84–105 % range, RSDs lower than 8 % for the complete analytical procedure, including extraction, and analysis of a reference sample. The reported method was applied to commercial chips and homemade potatoes showing results in good agreement with those published in the literature.

Ethyl carbamate (EC) is a naturally occurring component in fermented products, especially in Chinese yellow rice wine. A rapid and simple HPLC method is proposed for the simultaneous analysis of EC and urea in Chinese yellow rice wine. EC and urea reacted with xanthydrol (9H-xanthen-9-ol) under hydrochloric acid solution to produce fluorescent substances that could be quantified using FLD (λex = 234 nm, λem = 600 nm) after chromatographic separation from interferences. The determination results proved that such a method had good linear relationship (the correlation coefficient, R2 > 0.999), good repeatability (RSD

A sensitive GC-MS method has been established for the determination of acrylamide in surface and drinking water based on derivatization with xanthydrol. Deuterated acrylamide (acrylamide-d3 ) was chosen as the internal standard for analyzing the water sample. The derivatization of acrylamide was performed directly in water, and the best reaction conditions (xanthydrol of 1.6 mM, HCl concentration of 0.05 M, reaction for 30 min at ambient temperature) were established by variation of parameters. Under the established conditions, the detection and quantification limits were 3.0 and 9.7 ng/L, respectively, and the interday RSD was less than 8% at concentrations of 20 and 100 ng/L.

A sensitive and selective gas chromatographic mass spectrometric method, based on derivatization with 9-xanthydrol, has been established for the simultaneous determination of five carbamate pesticides (carbaryl, carbofuran, metolcarb, isoprocarb and ethiofencarb) in surface water. 4-Bromo-3,5-dimethylphenyl-N-methylcarbamate was chosen as the internal standard for analyzing water samples. The derivatization of carbamates was performed directly in water and the reaction conditions (9-xanthydrol of 50.0mM, HCl concentration of 0.05M, reaction for 60min at 60°C) were established through the optimization of various parameters. Under the established conditions, the limits of quantification were in the range of 0.007-0.028μg/L, and the intra- and inter-day relative standard deviation were each less than 15% at concentrations of 0.1, 1.0 and 10μg/L. None of the carbamate pesticides were detected in any of the sixteen surface waters analyzed.

A sensitive gas chromatographic mass spectrometric (GC–MS) method has been established for the simultaneous determination of acetamide (AA), propanamide (PA), and butyramide (BA) in surface and drinking water based on derivatization with 9-xanthydrol. Deuterated acrylamide was chosen as the internal standard for analyzing the water sample. The derivatization of AA, PA, and BA was performed directly in water and the reaction conditions (10.0-mM 9-xanthydrol, 0.5-M HCl, 20-min reaction time, and ambient temperature) were established. Under these conditions, the detection limit of the analytes was 0.03 μg L −1 , and the interday relative standard deviation was less than 16% at concentrations of 1.0, 5.0 and 10.0 μg L −1 . The proposed GC–MS method enables the reliable analysis of trace AA, PA, and BA in environmental water.

Urea nitrate (uronium nitrate, UN) is an improvised explosive that looks very much like sugar and is easily made from accessible starting materials, urea and nitric acid. During the last decade it has been frequently used by terrorists in the Israeli arena and in other countries as well. It is difficult to identify urea nitrate in post-explosion debris, since only a very small fraction survives the blast. Also, in the presence of water, it readily decomposes to its original components, urea and nitric acid, two ubiquitous substances with relatively low evidential value. By further modifying McCord's recent version of Clark's method for the detection of minute amounts of urea, we were able to identify with high degree of certainty traces of uronium ion, the main characteristic factor of urea nitrate, in post-blast residues by GC/MS. The analytical process is based on the initial formation of xanthenyl urea by the reaction of uronium cation with xanthydrol, followed by reaction with alcohol to form xanthylurethane, which is readily identified by GC/MS. The reaction mechanism was corroborated by the use of labeled (15)N-urea. By applying the technique to residues collected from scenes of controlled firing experiments, 4 out of 16 samples showed the presence of uronium cation as indicated by the formation of the corresponding xanthylurethane. Potential interferences such as urea and ammonium nitrate did not respond under standard conditions. However, under strongly acidic conditions (pH2), urea is converted into uronium ion, which is a nuisance, since it behaves as an authentic uronium cation. Such conditions, however, do not prevail at common crime scenes.

In the present work, the standard (p° = 0.1 MPa) molar enthalpies of formation of xanthydrol, 9-xanthenecarboxylic acid and 9-xanthenecarboxamide, in the gaseous state, at T = 298.15 K, were determined by experimental and computational studies. The experimental techniques used were the static-bomb combustion calorimetry, which enabled the determination of the standard molar enthalpy of formation, in the crystalline state, and the vacuum drop microcalorimetric and the Knudsen effusion techniques used to derive the enthalpy of sublimation. For comparison purposes, we performed standard ab initio molecular orbital calculations, using the G3(MP2)//B3LYP composite procedure, of the enthalpies of several homodesmotic reactions, allowing to extract the standard molar enthalpies of formation, in the gaseous state, of the three xanthene derivatives considered in this work. The calculated results are in good agreement with the experimental data.

Acrylamide levels in commercially available potato chips in Japan were monitored between August 2006 and June 2010 using the xanthydrol derivative gas chromatography-mass spectrometry (GC-MS) method. Seasonal and annual changes in acrylamide concentrations were determined. Nationwide bimonthly sampling of potato chips was carried out using a four-level design, and seasonal variations were detected in which the minimum acrylamide concentration was observed in August, and the maximum between February and June. Seasonal variations became less apparent after August 2008 as a result of annual effects and/or mitigation measures taken by the potato chip producers. Sampling uncertainties were separated into time-to-time, city-to-city, and lot-to-lot variation, and the largest variation was shown to be lot-to-lot including bag-to-bag.

A novel GC-MS method was developed for the determination of acrylamide, which is applicable to a variety of processed foods, including potato snacks, corn snacks, biscuits, instant noodles, coffee, soy sauces and miso (fermented soy bean paste). The method involves the derivatization of acrylamide with xanthydrol instead of a bromine compound. Isotopically labelled acrylamide (d₃-acrylamide) was used as the internal standard. The aqueous extract from samples was purified using Sep-Pak™ C₁₈ and Sep-Pak™ AC-2 columns. For amino acid-rich samples, such as miso or soy sauce, an Extrelut™ column was used for purification or extraction. After reaction with xanthydrol, the resultant N-xanthyl acrylamide was determined by GC-MS. The method was validated for various food matrices and showed good linearity, precision and trueness. The limit of detection and limit of quantification ranged 0.5-5 and 5-20 µg kg⁻¹), respectively. The developed method was applied as an exploratory survey of acrylamide in Japanese foods and the method was shown to be applicable for all samples tested.

Clarithromycin used for the treatment of respiratory tract infection. Anew alternative simple, rapid, sensitive, and selective high-performance thin-layer chromatography (HPTLC) method was developed and validated for the estimation of clarithromycin in plasma. HPTLC analysis was performed on pre-coated silica gel 60F254 plates. Separation was carried out using ethyl acetate-methanol-15% ammonium acetate (pH 10.6) as solvent system. Densitometry measurements were performed in absorbance mode at 506 nm after derivatising with xanthydrol solution. The RF of the drug was found to be 0.62. The method was linear over the range of 0.1–3.0 μg mL−1 (r2 = 0.9974). The mean extraction recoveries were over 85%. The intra-day and inter-day precision (%CV) of the assay was in the range of 0.79–4.55%. The accuracy was found to be above 95%. The method was successfully applied to a pharmacokinetic study of clarithromycin 250 mg tablet in healthy human male volunteers.

In this paper we have adapted a technique, previously used to determine the presence of urea in aqueous samples of wine and urine, to detect trace levels of urea nitrate explosives. The procedure involves the reaction of the uronium ion (protonated urea) with a fluorophore, xanthydrol. By modification of the procedure to utilize non-aqueous reagents, in neutral conditions, it can be made specific to the presence of the urea nitrate ion pair. The procedure includes selective detection of derivatization products by UV and fluorescence following separation by High-Performance Liquid Chromatography (HPLC). Analytical method development included optimization of HPLC conditions (solvent, gradient), UV and fluorescence wavelengths, and derivatization parameters (xanthydrol amount, reaction times, temperature). The extraction of urea nitrate from surfaces was also investigated and optimized. For best quantification, it was shown that an internal standard was required; this resulted in a quantification limit around 0.17mM (21mg/L). The entire procedure could be performed in less than 30min per sample and potential interferences such as ammonium, nitrate, and urea did not produce a response under standard conditions.

A robust and selective method for the determination of ethyl carbamate in double-distilled fruit brandies (“palinka” spirits) by HPLC-ESI-MS/MS is described in the study. The approach is based on the combination of xanthydrol derivatization and the multiple reaction monitoring (MRM) of xanthyl-ethyl carbamate. Interestingly, this compound could only be ionized with adequate intensity through [M + Na] + adduct formation, similarly to some of the carbamate derived pesticides, as investigated with the help of synthesizing the commercially unavailable standard. 20 traditional spirit samples originating from 14 fruit species were analyzed with the developed method, showing high selectivity and fruit-dependent sensitivity, thus requiring standard addition for quantification purposes. The concentration range of ethyl carbamate in the spirit samples was between the detection limit (0.003 mg L −1 ) and 2.6 mg L −1 . The study indicated that besides the usually high ethyl carbamate containing, stone fruit derived spirits namely, plum ( Prunus domestica L.) and sour cherry ( Prunus cerasus L.), spirit samples of quince ( Cydonia oblonga Mill.), a non-stone fruit species, showed relatively high ethyl carbamate levels close to or exceeding the actual European recommendation of 1 mg L −1 . As quince is not known to contain either high amounts of cyanogenic glucoside or N-carbamyl-amino acids, this phenomenon cannot be actually referred to genuine inner parameters of this fruit.

Two cases of digitalis poisoning are described. Case 1, a man, aged 40 years, swallowed for suicidal purposes about 50 digitalis tablets, each containing 50 mg standardized digitalis leaf, digitalis purpurea (0.5 i.u.). Death occured about 8 hours after the intake. A quantitative determination of digitalis glycoside in the gastric contents, and in the contents of the small intestine, blood and heart was performed with xanthydrol. Case 2, a child, 11 days old, because of a congenital heart disease was treated with digoxin. 1/2-1 hour before death the child was given 0.7 mg digoxin intravenously. A quantitative determination of digoxin was performed with xanthydrol in the liver, heart and lung and by the fluorometric method in the liver, heart, kidney, urine and blood.

In this research, for the first time, we successfully developed ultrasonic-assisted extraction and dispersive liquid-liquid microextraction combined with gas chromatography-mass spectrometry as a new, fast and highly sensitive method for determining of acrylamide in potato chips samples. Xanthydrol was used as a derivatization reagent and parameters affecting in the derivatization and microextraction steps were studied and optimized. Under optimum conditions, the calibration curves showed high levels of linearity (R2 > 0.9993) for acrylamide in the range of 2–500 ng mL−1. The relative standard deviation (RSD) for the seven analyses was 6.8%. The limit of detection (LOD) and limit of quantification (LOQ) were 0.6 ng g−1 and 2 ng g−1, respectively. The UAE-DLLME-GC-MS method demonstrated high sensitivity, good linearity, recovery, and enrichment factor. The performance of the new proposed method was evaluated for the determination of acrylamide in various types of chips samples and satisfactory results were obtained.

We conducted the biotransformation of 4-chromanol, 4-flavanol and xanthydrol using Italian parsley ( Petroselinum neapolitanum) callus or soybean ( Glycine max) callus as biocatalysts. The biotransformation of 4-chromanol using P. neapolitanum yielded 4-chromanone at 5% on day 3, 12% on day 5, 23% on day 8, 21% on day 11, 25% on day 14, 22% on day 17, and a final yield of 22% on day 20. Although the reaction appeared to level off between days 8 and 20, we verified that the oxidation reaction continued to progress, albeit very gradually, until day 20. Furthermore, biotransformation of 4-flavanol using G. max callus yielded flavanone at 24.8% after 70 days. Moreover, biotransformation of xanthydrol using G. max yielded xanthone at 19.8% on day 1, 72.8% on day 2, 93.1% on day 4, and 96.3% on day 6. Addition of NADP accelerated the reaction, suggesting that an oxidoreductase may be involved. In contrast, there were no observable reverse reactions for 4-chromanone, 4-flavanone, or xanthone using the respective biocatalysts. Therefore, callus cells can be used as biocatalysts for the oxidation of alcohols to ketones. Organic synthetic reactions mimic environmentally-friendly reactions using biocatalysts found in nature.

Contamination of food and food packaging material by rodent urine is evidence of insanitary conditions. Urea from rodent urine is used as a chemical indicator of contamination. The limit of detection of the xanthydrol/urea AOAC Method 959.14 by formation of dixanthylurea crystals is 4 μg urea isolated from urine on packaging material. Six different lots of xanthydrol from 5 different manufacturers were compared. Differences in urea detection sensitivity of the xanthydrol of up to 1000-fold were observed. Melting points showed further evidence of variability and impurities in xanthydrol lots. A liquid chromatographic method was developed to separate and identify the impurities. Confirmation of analytes was performed by gas chromatography/mass spectrometry.

The current AOAC method (963.28) for large-scale (50 g) testing of urine on grain is based on the reaction of sodium in urine with magnesium uranyl acetate. Detection of sodium suggests that urine is present and that a test for urea is appropriate. Urea is detected with urease-bromothymol blue-paper and is confirmed through its reaction with xanthydrol to form dixanthylurea crystals, which are detected microscopically. The initial nonspecific test for sodium can be influenced by the presence of salt or other sodium compounds. Furthermore, the magnesium uranyl acetate spray used in Method 963.28 potentially exposes the analyst to the aerosol of a volatile, toxic uranium compound. Excess reagents and analyzed test portions must be disposed of as radioactive waste. In addition, Method 963.28 requires several steps to determine the presence of urea. The alternative AOAC method (972.41) tests for the presence of urea from urine on individual seeds. Urea is enzymatically decomposed to ammonia and carbon dioxide by urease.Liberated ammonia shifts the pH, changing the color of the indicator in the agar from yellow to blue. This study adapts Method 972.41 to larger test samples. Up to 25 g grains and seeds are sprayed with urease test agar instead of being individually immersed in the urease test agar. The modified method was used to analyze urea on seeds and grains of 24 plants from 4 families. The method has a limit of detection of one seed contaminated with 1μg urea.

The 9-(4-methoxyphenyl)xanthylium ion (AnX+), a bulky cation that according to molecular modeling simulations cannot enter through the 7.4 A pore opening of tridirectional large-pore zeolites Y and β, has been prepared by ship-in-a-bottle synthesis within the supercages of these two zeolites. The synthetic procedure involves two steps: (i) generation of xanthylium cation (X+) adsorbed within the zeolite by treatment of xanthydrol onto the H+ form of these solids; (ii) electrophilic attack of the cation to anisole within the framework of the zeolite. Carrying out the same procedure using toluene or benzene or using an alternative process involving the reaction of xanthone with anisole, led to the corresponding 9-arylxanthylium ions together with some unidentified adventitious material. Textural and acidic properties of these composites were tested using α-methylstyrene dimerization and were found to be very similar to the original HY or Hβ zeolites, thus indicating an internal location for AnX+. Entrapmen...

An efficient synthesis of 9H-xanthene-9-carboxaldehyde (3a), 9H-thioxanthene-9-carboxaldehyde (3b), and 9,10-dihydro-10-methyl-9-acridinecarboxaldehyde (3c) by a novel two-carbon homologation of xanthydrol (1a), thioxanthydrol (1b), and 9,10-dihydro-10-methyl-9-acridinol (1c), respectively, using N-vinylacetamides (2a,b) or ethyl vinyl ether (2c) as acetaldehyde anion equivalents, is described.

Ethyl carbamate (EC) is a common substance in fermented foods and drinks, and its quantification is important because of its carcinogenic nature and its usually presence in alcoholic beverages. The present work involved the development and validation of an analytical method for the evaluation of EC in cachaca by HPLC-FLD after previous derivatization with xanthydrol. The method presented a mean recovery of 94.88%, an intra-day precision of 4.19% (30.0 μgL(-1)) and 3.32% (75.0 μgL(-1)), a coefficient of determination (r(2)) equal to 0.9985, and limits of detection and quantification equal to 6.39 and 21.32 μgL(-1), respectively. The results show that the analytical method is accurate, reproducible and linear over the concentration range from 5.0 to 160 μg of EC per litre. The method was applied to the analysis of EC in cachaca, the analyses being rapid and efficient.