Capillary electrophoresis as an alternative to HPLC for determination of honey flavonoids

Summary The general objective is to provide an alternative methodology based on capillary electrophoresis (CE) to characterize flavonoids from honey and hence determine its botanical origin. The specific objective is to compare the separation of flavonoids by CE with those achieved by HPLC to assess CE as an alternative technique for the determination of honey flavonoids. Fourteen different flavonoids isolated from honey were analysed by MECC and compared to the HPLC separations. It was difficult to find specific experimental conditions to separate all the flavonoids from honey in a single MEKC run. Three chromatographic conditions are optimized and, depending on the flavonoid markers sought in honey, the appropriate detection method should be chosen. Compared to the HPLC results, it is clear that CE could be an alternative technique in honey flavonoids analysis and particularly in the study of its geographical and floral origin.     

Development of honey hydrogel dressing for enhanced wound healing

Radiation at 25 and 50 kGy showed no effect on the acidic pH of the local honey, Gelam, and its antimicrobial property against Staphylococcus aureus but significantly reduced the viscosity. Honey stored up to 2 years at room temperature retained all the properties studied. Radiation sterilized Gelam honey significantly stimulated the rate of burn wound healing in Sprague-Dawley rats as demonstrated by the increased rate of wound contraction and gross appearance. Gelam honey attenuates wound inflammation; and re-epithelialization was well advanced compared to the treatment using silver sulphadiazine (SSD) cream. To enhance further the use of honey in wound treatment and for easy handling, Gelam honey was incorporated into our hydrogel dressing formulation, which was then cross-linked and sterilized using electron beam at 25 kGy. Hydrogel with 6% of honey was selected based on the physical appearance.     

高效液相色谱法分析蜂蜜中的糖

本文研究了用四乙撑五胺（简称ＴＥＰＡ）作为胺基改善剂，在硅胶柱上定量分析蜂蜜含糖量的方法，并成功地分离了木糖、果糖、葡萄糖、蔗糖、麦芽糖和乳糖。对操作条件进行了探讨。采用示差折光检测器检测，含０．０１％ＴＥＰＡ的乙腈－水（７７＋２３）作流动相。六种糖的相对标准偏差均小于３．５％。     

Analysis of Chloramphenicol Residues in Honey by Liquid Chromatography–Tandem Mass Spectrometry

Antibiotics are often used in bee-keeping to control European and American foulbrood. The broad spectrum antibiotic chloramphenicol (CAP) was used for curative purposes in veterinary medicine, but is now forbidden in numerous countries, although still used in south-east Asia. A liquid-chromatographic method with tandem mass spectrometric detection (LC–MS–MS) has been developed for analysis of sub-g kg^–1 residues of chloramphenicol in honey. Results from full validation of the procedure and analysis of 75 honey samples obtained commercially in Switzerland are presented. These show the method is satisfactory and useful for monitoring chloramphenicol residues in honey.     

Rapid and sensitive method for determining free amino acids in honey by gas chromatography with flame ionization or mass spectrometric detection

This paper describes a rapid, sensitive and specific method for determination of free amino acids in honey involving a new reaction of derivatization and gas chromatography (GC) with flame ionization (FID) and mass spectrometric (MS) detection. The method allows the determination of 22 free amino acids in honey samples in a short time: 8 and 5 min for GC-FID and GC-MS, respectively. Quantitation was performed using Norvaline as internal standard, with detection limits ranging between 0.112 and 1.795 mg/L by GC-FID and between 0.001 and 0.291 mg/L by GC-MS in the selected-ion monitoring mode. The method was validated and applied to a set of 74 honey samples belonging to four different botanical origins: eucaliptus, rosemary, orange and heather. The statistical treatment of data shows a correct classification of different origins over 90%.     

Fluorometric quantification of total d-gluconate by a flow-injection system using an immobilized-enzyme reactor

A method for the quantification of total d-gluconate by flow-injection analysis was developed using an immobilized-enzyme reactor and fluorescence detection. d-Gluconate was quantified using co-immobilized gluconate kinase (GK) and 6-phosphogluconate dehydrogenase (PGDH) reactor. d-Gluconate was phosphorylated to 6-phospho-d-gluconate by GK in the presence of ATP, and then the 6-phospho-d-gluconate produced was oxidized by PGDH with NADP⁺. The NADPH produced by the GK-PGDH reactor was monitored fluorometrically at 455 nm (excitation at 340 nm). A linear relationship between the responses and concentrations of d-gluconate was obtained in the ranges of 1.0 × 10⁻⁶–1.6 × 10⁻⁴ M. The relative standard deviation for 10 successive injections was 0.57% at the 0.1 mM level. This analytical method was applied to the quantification of d-gluconate in honeys, vinegars and noble rot wines, and the results showed good agreement with those obtained using the conventional F-kit method.     

Mineral content and botanical origin of Spanish honeys

Eleven elements (Zn, P, B, Mn, Mg, Cu, Ca, Ba, Sr, Na and K) were determined by inductively plasma coupled spectrometry in 40 honey samples from different places of Spain and four different botanical origins: Eucalyptus (Eucalyptus sp.), Heather (Erica sp.), Orange-blossom (Citrus sinensis) and Rosemary (Rosmarinus officinalis). K, Ca and P show the higher levels with average concentrations ranged between 434.1-1935 mg kg⁻¹ for K; 42.59-341.0 mg kg⁻¹ for Ca and 51.17-154.3 mg kg⁻¹ for P. Levels of Cu (0.531-2.117 mg kg⁻¹), Ba (0.106-1.264 mg kg⁻¹) and Sr (0.257-1.462 mg kg⁻¹) are the lowest in all honey samples. Zn (1.332-7.825 mg kg⁻¹), Mn (0.133-9.471 mg kg⁻¹), Mg (13.26-74.38 mg kg⁻¹) and Na (11.69-218.5 mg kg⁻¹) concentrations were found strongly dependent on the kind of botanical origin.Results were submitted to pattern recognition procedures, unsupervised methods such as cluster and principal components analysis and supervised learning methods like linear discriminant analysis in order to evaluate the existence of data patterns and the possibility of differentiation of Spanish honeys from different botanical origins according to their mineral content. Cluster analysis shows four clusters corresponding to the four botanical origins of honey and PCA explained 71% of the variance with the first two PC variables. The best-grouped honeys were those from heather; eucalyptus honeys formed a more dispersed group and finally orange-blossom and rosemary honeys formed a less distinguishable group.     

蜂蜜中四环素族抗生素残留量的薄层色谱测定法

残留在蜂蜜中的四环素族抗生素在经Ｓｅｐ－ＰａｋＣ１８小柱固相萃取处理后，用高效正相薄层色谱予以分离，喷雾显色后用紫外灯进行定性分析；使用双波长薄层扫描仪进行定量测定。在蜂蜜中的添加量为００５０×１０－３、０１０×１０－３及０２０×１０－３时，强力霉素（ＤＣ）、土霉素（ＯＴＣ）和四环素（ＴＣ）的回收率分别为９１６％～１００３％、８４５％～１０３１％和７７０％～１０３２％。该法的测定低限可达到１０－３μｇ。     

液相色谱-串联质谱法测定蜂产品中吡虫啉及其3种代谢物

建立了蜂蜜和蜂花粉中吡虫啉及其代谢物吡虫啉烯烃、吡虫啉脲、6-氯烟酸的液相色谱-串联质谱(LC-MS/MS)检测方法.在QuEChERS方法基础上,针对目标物化学性质和样品杂质情况,对提取溶液的pH值、提取次数、净化材料等参数进行了优化.最终以5％甲酸-乙腈溶液提取两次,无水MgSO4、NaCl盐析分层,提取液经增强型脂类去除材料(EMR)净化,以LC-MS/MS进行测定,基质外标法进行定量分析.结果表明,蜂蜜和蜂花粉中吡虫啉、吡虫啉烯烃、吡虫啉脲、6-氯烟酸的平均加标回收率为86.0％～111.5％, 相对标准偏差在1.7％～9.6％之间, 检出限分别为0.20, 3.50, 0.40和14.00 μg/kg,定量限分别为0.60, 11.64, 1.20和45.00 μg/kg.本方法分析速度快、灵敏度高、重现性好,适用于蜂蜜和蜂花粉中吡虫啉及其3种代谢物的快速测定.     

高效液相色谱/安培检测法测定蜂蜜中苯酚残留量

研究了用高效液相色谱 /安培检测法测定蜂蜜中苯酚残留量。考察了试验参数对测定结果的影响。在所选试验条件下 ,苯酚保留时间约为 12min ,检出限为 2 .0ng·g- 1。三组不同水平的加样回收率为 91.6 10 1.9% ,相对标准偏差 2 .812 .8%。测定结果满意