Chiral volatile compounds for the determination of orange honey authenticity

Assessment of the botanical origin of the unifloral honeys is of great concern in the context of consumer protection and quality control. Nevertheless, the methods that are currently available are not satisfactory. In order to find alternatives to the time consuming and uncertain methods, a new analytical approach is proposed; it is based on the enantiomeric ratio investigation of chiral volatile constituents which are derived from the plants being visited by the bees. The method was applied to orange honeys; firstly, the volatile fraction of orange honey and flowers were studied by SPME-GC-MS; a large number of components were identified in orange honeys while linalool prevailed among orange flower volatiles. The enantiomeric ratios of linalool and its oxides were determined and analogous values between honey and flowers resulted. Even if a wide variability in the amount of typical volatile constituents of orange honeys emerged, the enantiomeric ratios of linalool and its oxides remained stable and thus less influenced by production period, conditioning, packaging, storage, etc. As a result the enantiomeric distribution of the honey volatile constituents that directly come from flowers could represent a rapid and easy method for floral origin authenticity.     

Multiclass determination of 27 antibiotics in honey

A multiclass approach for the screening and confirmation of antimicrobial substances in honey has been developed and validated according to Commission Decision 2002/657/EC. A total of 27 basic drugs belonging to sulfonamide, nitroimidazole and quinolone families were determined. Sample preparation consisted in an acidic hydrolysis of honey followed by a double purification step (defatting and strong cation exchange solid-phase extraction). Instrumental determination was performed by liquid chromatography tandem mass spectrometry (LC–MS/MS) operating in positive electrospray ionization mode. Chromatographic separation was performed on a Poroshell 120 EC-C18 column (100 × 3.0 mm, 2.7 μm) using a gradient with acetonitrile and water both containing 0.1% of formic acid. The method was validated in the range 0.1–10 μg kg⁻¹ evaluating selectivity, linearity, precision, trueness, matrix effect, decision limits and detection capabilities. Satisfactory performances were obtained for all the analytes, although important differences were observed in function of the honey type.The procedure was applied to the analysis of 74 honey samples of different botanical origins and geographical provenience collected from the Italian market. In nine honeys (12%) trace levels of sulfonamides were confirmed. The found levels (lower than 2 μg kg⁻¹) do not raise concerns with respect to the public health.     

Alternatives to official analytical methods used for the water determination in honey

A modified Karl Fischer (KF) titration method (measurements at 50°C instead of room temperature) for the precise determination of the water content in honey has been developed together with the adjustment of a drying method using an infrared (IR) technique. The results obtained by this IR method applying a temperature between 98–100°C were found to be very similar to those obtained by the KF technique. In the second part of the study, the water concentration was determined in 39 authentic honey samples from various geographical and botanical origins using four different techniques: KF titration, refractive index measurements, official oven-drying method and a special oven method. Significant differences could be observed (maximum differences were in the range 0.9–5.1% absolute). The results obtained by KF titration were found to have the lowest standard deviations. With the exception of a few honey varieties, this method led to the highest values.     

Easy and rapid method for the quantitative determination of pyrrolizidine alkaloids in honey by ultra performance liquid chromatography-mass spectrometry: An evaluation in commercial honey

Pyrrolizidine alkaloids (PAs) are toxins biosynthesised by plants and they are known to be present in approximately 6000 plant species, about 3% of all flowering plants. PAs are probably the most widely distributed natural toxins and represent a potential risk to human health, since poisoning caused by these toxins is associated with acute and chronic liver damage and may lead to death. One of the most common sources of PAs exposure in humans is honey consumption. We have developed a quick and easy method to quantify nine different PAs (echimidine, heliotrine, intermedine, lycopsamine, lasiocarpine, retrorsine, seneciphylline, senecionine, senkirkine) in honey based on QuEChERS sample extraction and ultra fast liquid chromatography coupled with mass spectrometry detection. We performed a validation study of the method and it resulted in good precision and accuracy, high recoveries, and good linear calibrations. The limit of detection ranged from 0.021 to 1.39 μg Kg⁻¹ and the limit of quantification from 0.081 to 4.35 μg Kg⁻¹. This new approach was applied to the quantification of PAs in retail honeys purchased in local supermarkets, classified by their country of origin: Italian honeys, blends of honey of European countries and blends of honey of European and non-European countries. The concentrations detected ranged from 1 to 169 μg PAs/kg⁻¹ with higher concentrations in blends of European and non-European honeys. This study reveals that many samples tested would exceed the tolerable daily intake suggested for these substances and they could be a hazard to human health.     

Comparison between Karl Fischer and refractometric method for determination of water content in honey

The aim of this work was to compare refractometric index (RI) and Karl Fischer (KF) titration methods for water content measurement in honeys. In addition, the effectiveness of two different solvents (methanol (M) and methanol:formamide in the ratio 1:1 (M + F)) was evaluated.Results indicated that RI and KF methods yielded similar results for water content determination in honeys; mainly, when the solvent M + F was used. This solvent mixture (M + F) also allowed a reduction in titration time which may be a potential advantage for measuring water content in honey.     

A HPLC with fluorescence detection method for the determination of tetracyclines residues and evaluation of their stability in honey

A high-performance liquid chromatography with fluorescence detection method for the simultaneous determination of oxytetracycline (OTC), tetracycline (TC) and chlortetracycline (CTC) residues in honey was developed and validated. Sample preparation was done in a single solid phase extraction step. The chromatographic separation was performed on a C₈ column. Matrix matched calibration curves showed linearity higher than 0.99. The accuracy values lay between 86% and 111% and the precision was lower than 11%. Limits of detection and quantitation were 8 μg kg⁻¹ and 25 μg kg⁻¹, respectively. The method was employed to evaluate the stability of the tetracyclines in honey during 60 days of storage. The residue levels of OTC, TC and CTC were reduced 97%, 76% and 71%, respectively. Honey samples (n = 22) collected from the retail market were analyzed. No tetracyclines residues were detected.     

致密油储层孔隙度测定方法

致密油储层孔隙结构以微孔和纳米级孔隙为主,孔隙度一般小于10%。常规孔隙度测定方法很难准确、快速测定致密油储层孔隙度。因此,基于波义耳定律,同时引入孔隙度测定压力区分度函数,分析不同参数对孔隙度测定精度的影响,优化实验仪器参数,设计出适合致密油储层孔隙度测定的实验装置。利用该实验装置测定致密油储层岩心样品孔隙度为2.55%,而利用压汞法测定的孔隙度为2.40%,2种方法的测定结果相差不大。为了验证优化后的实验装置的准确性,利用该实验装置对已知孔隙度为25.16%的人造岩心的孔隙度进行测定,其值为25.56%,表明优化后的实验装置能够快速、准确测定致密油储层岩心样品的孔隙度。     

The impact of honey fraud information on the valuation of honey origin: Evidence from an incentivized economic experiment

While the adulteration or mislabeling of products as honey, or honey fraud, is a major concern for industry and regulators—leading to a burgeoning research literature on documenting characteristics of authentic, place-specific honey and developing new methods of detecting honey fraud, there is little evidence about the impact of honey fraud occurrence on consumer preferences. Studying consumer response to honey fraud is complicated by the unpredictable nature of detection of fraud and consumer exposure to information about fraud, which makes consumer experiments a valuable tool for understanding consumer response to honey fraud. In this binding valuation experiment, we examine consumer willingness to pay for four types of honey before and after exposure to honey fraud information (versus a control group): imported, domestic (US), local (Lincoln, Nebraska), and organic (no origin specified) honey. When consumers do not have information about honey fraud, they do not value US honey any more than imported honey, though they are willing to pay a premium for both organic and local honeys. When consumers read information about honey fraud, their valuation of imported honey decreases significantly—by over 20%. Valuation of the organic honey also decreases, though by a smaller amount (4%). On the other hand, valuation of both US and local honey increases. The combined effect of the decreased valuation of imported honey and increased valuation of US-produced honey yields a significant increase in the premiums that consumers are willing to pay for US and local honey over the imported honey. The results suggest that increased consumer awareness about honey fraud may lead to stronger preferences for honey produced in the US.     

Methods for improving the utilization of water in a petroleum refinery

Conclusions Complexes of purification installations designed for modern petroleum treatment and petrochemical plants are of high cost. Their operation demands large monetary expenditures.The high individual capital investments and operating expenses for the purification of the streams are due to the large amounts of waste waters and their high degree of contamination.Design organizations are making very poor use of existing, sufficiently tested, technical solutions, which make it possible to reduce considerably the flows of waste waters and to decrease the discharge of contaminated streams into the water reservoirs of the country.With a considerable decrease in the amount of waste waters and a lowering of their contamination, there is the possibility, by purification, of bringing the quality of the stream before discharge up to the quality of the water in the water reservoirs.For individual regions of the country, it is possible to design plants without discharge of waste waters into a water reservoir, by maximum water recirculation and by pumping part of the streams into absorption bore holes, as well as by the use of the purified streams for spraying or for steam production.Construction of installations, designed taking into account new technical solutions for water utilization, and the introduction of progressive methods for purification of the streams, with the use of efficient equipment, makes it possible to reduce the capital investments and the operating expenses.The flowsheet for water supply and sewage disposal in petroleum treatment plants, developed in 1957 by the Giproneftezavody and Giprospetspromstroi institutes, must be revised as soon as possible, the necessary changes made in it, and new design standards set.The present article is the continuation of an article by Ya. G. Gorkin, begun in No. 1, 1968.Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 2, pp. 1–5, February, 1968.     

Improving DNA isolation from honey for the botanical origin identification

Honey is a natural product highly consumed due its known association with health benefits. Monofloral honeys are perceived as better quality products, being the most appreciated by consumers, thus attaining higher market values. Therefore efficient tools are needed as alternatives to the classical microscopic analysis presently used for the botanical origin identification of honey. In the present work, the use of DNA-based methods for the botanical species identification of honey is proposed. For this purpose, five DNA extraction methods (the kits NucleoSpin Plant (methods A and B) and DNeasy Plant Mini Kit, and the in-house CTAB-based and Wizard methods) combined with three different sample pre-treatments were applied to four honey samples (3 monofloral honeys of Calluna vulgaris, Lavandula spp. and Eucalyptus spp. and one multifloral honey). The 15 DNA extraction protocols were compared in terms of DNA integrity, yield and purity, as well as capacity of amplification targeting universal and adh1 specific genes of C. vulgaris. The results demonstrated the superior efficacy of the Wizard method in terms of DNA quality and amplification capacity, when combined with the sample preparation treatment with a mechanical disruption step of pollen to improve DNA yield. Although with considerable lower DNA yields, the CTAB and DNeasy methods were also successful because both were able to clearly amplify heather DNA from the monofloral heather honey.     

微量法和雷德法测定石油产品蒸汽压的应用对比

本文对石油产品两种蒸汽压测定方法进行了详细的对比分析,同时对两种方法的准确性和重复性进行了考察验证,结果表明,两种方法的准确性和重复性结果都较好,但微量法的结果更优于雷德法,由于微量法所用样品量少、分析时间短,克服了雷德法测量时人为的操作误差,可以满足炼油厂的日常分析要求,因此实际中应优先选用微量法,雷德法作为备用。     

Development of a novel sensitive molecularly imprinted polymer sensor based on electropolymerization of a microporous-metal-organic framework for tetracycline detection in honey

Electrochemical sensor for the detection of tetracycline, based on a gold electrode surface modified with a molecularly imprinted polymer microporous-metal-organic framework, is described. Imprinted gold nanoparticles composites are assembled on Au surfaces by the electropolymerization of p-aminothiophenol functionalized gold nanoparticles in the presence of the imprint molecule. The electrochemical sensor was characterized by linear sweep voltammetry in the presence of hexacyanoferrate/hexacyanoferrite as redox probe. In order to achieve optimal preconcentration, the influence of various parameters such as extraction and incubation times, washing and eluting solutions was evaluated. The sensor showed a linear range from 224 fM to 22.4 nM and a limit of detection of 0.22 fM. The proposed method was successfully applied to determine tetracycline in honey. The recoveries of tetracycline are in the range of 101.8 %−106.0 % with an RSD ≤8.3%.     

离子液体中纤维素催化转化制5-羟甲基糠醛

 采用1-丁基-3-甲基咪唑离子液体(BmimCl)为溶剂,以磺酸功能化离子液体N-(4-磺酸基)丁基三甲胺硫酸氢盐和CrCl₃氯化为催化剂,开展了纤维素一锅法催化转化制5-羟甲基糠醛(HMF）的研究。采用高效液相色谱分析了液体产物。分别考察了催化剂种类、用量、反应温度和时间对纤维素转化的影响。结果表明,使用离子液体为溶剂,磺酸功能化离子液体和CrCl₃协同作用,将纤维素转化为HMF。当反应在130℃下,磺酸功能化离子液体、CrCl₃和纤维素的摩尔比为5∶4.5∶100时,HMF 收率和产物总收率分别为41%和51%。     

Mixture-risk-assessment of pesticide residues in retail polyfloral honey

The presence of even tiny quantities of pesticide residues in honey, a traditional healthy product, is a matter of concern for producers, packers and consumers. This paper aims to quantify pesticides in retail brands of polyfloral honey, and to calculate the mixture risk assessment of honey for consumers according to the results obtained from the analysed samples. A LC-MS/MS multi-residue method was developed and validated for 13 compounds: 11 pesticides (chlorfenvinphos, coumaphos, tau-fluvalinate, amitraz, which are very common in veterinary treatments, and imidacloprid, acetamiprid, simazine, cyproconazole, tebuconazole, chlorpiryphos-methyl, chlorpiryphos, widely used in agricultural practices), and 2 metabolites of amitraz (2,4-DMA and 2,4-DMF). Results showed that the samples contained pesticide residues at different concentrations; however, the MRL in honey for each of the 11 pesticides was never exceeded. The most common were amitraz (from 1 to 50 μg/kg) present in 100% of the samples, and coumaphos (up to 14 μg/kg) in 63%. The hazard index (HI) for adults was less than 0.002 in all cases, a long way from 1, the value established as the limit of acceptability. Therefore, commercial honey does not represent any significant risk to health. However, considering that residue levels should be present “as low as reasonably achievable” it is deemed necessary to make an effort to reduce their presence by appropriate agricultural and, above all, beekeeping practices due to acaridae treatments.     

Methods of reliability determination and designing of reliability tests of mechanical structures

Brief tests of methods of reliability assessment and designing of tests of mechanical structures, applying static, impact, heat, and vibration loads, including those based on a small volume of tests, are given. The methods are provided with PC software. __________ Translated from Khimicheskoe i Neftegazovoe Mashinostroenie, 42, No. 3, p. 39, March, 2006.     

Incidence of Clostridium botulinum spores in honey in Turkey

A total of 48 honey samples were analysed for Clostridium botulinum spores. Samples were prepared by direct addition (DA), dilution centrifugation (DC) and supernatant filtration (SF) methods and cultured in cooked meat medium (CMM) and trypticase peptone glucose yeast (TPGY) enrichment broths were used for the isolation of C. botulinum spores. The DC method was found most efficient while CMM enrichment broth was more successful than TPGY. Six of analysed 48 honey samples were C. botulinum positive (12.5%). Results indicated that honey sold in retail markets of Ankara found to be significantly (12.5%) contaminated with C. botulinum.     

Single-laboratory validation of a liquid chromatography method for the determination of patulin in apple juice

A method for patulin determination in apple juice was optimized and single-laboratory validated. Patulin was extracted with ethyl acetate and the extracts were cleaned-up in a column prepared in the laboratory. The determination was carried out by liquid chromatograph with a C₁₈ column and diode array detector. Linearity was observed from 25.4 to 532.5 μg/L. Mean recovery of 81.6% and relative standard deviations <5.7% were obtained for samples spiked with 27, 58 and 122 μg/L. Limits of quantification and detection were 10 and 4 μg/L, respectively. In the ruggedness experiment, seven factors were considered. The method presented the advantages of easiness, economical aspects, patulin identity confirmation and use of non-toxic solvents and reagents.     

Karl Fischer Titration to determine moisture in honey: A new simplified approach

Honey, produced by Apis mellifera from nectar or honeydew, contains a discrete quantity of water (about 17%). The variability of water content influences the quality, the stability, the workability and the storage of honey. Moisture in honey is usually measured via determination of refractive index (RI); from the value measured, the percentage is calculated by an empirical formula or by “conversion” table. A possible alternative approach is the Karl Fischer Titration (KFT). The objective of this work was to find the optimal parameters for water determination in honey with KFT without any heat treatment of sample or working medium and the measurement of water content in more than 100 honeys of different botanical origin, using RI and KFT determinations. The water content, obtained with KFT, was usually higher than that determined by RI analysis. According to our results KFT seems to be the most reliable method.