HPLC法测定库克Noni果汁中游离态水溶性维生素

采用HPLC法测定Noni果汁中游离态的抗坏血酸（Vc）、硫胺素（VB1）和烟酰胺（VB5），其测定条件为：色谱柱为Alhima C18柱，流动相为甲醇-0．01％磷酸（3：7，V／V），流速为1．0mL／min，进样量为20μL，柱温为室温，采用二极管阵列检测器在251nm下检测。在上述色谱测定条件下三种维生素能得到良好分离。结果表明，该方法灵敏度高，定量准确，重现性好，回收率高。昕测Noni果汁中三种维生素的含量分别为：Vc0．354mg／mL，VB10．0663mg／mL，VB50．131mg／mL。说明Noni果汁中三种必需维生素含量丰富，可作为维生素缺乏的营养补充剂；所建立的测定方法可作为一种Noni果汁生产质量控制方法。     

Determination of organic acid impurities in lactic acid obtained by fermentation of sugarcane juice

Lactic acid produced by fermentation process mostly contains a number of aliphatic carboxylic acids as impurities. In this work, carboxylic acid impurities in lactic acid samples from a number of sources were determined at ppm levels. A simple HPLC method was developed that utilized a new generation polar embedded reverse phase, 20mM phosphate buffer at pH 2.20 (±0.05) and UV detection at 210 nm. The method enabled quantitative analysis of the above acids in lactic acid matrix. The experimental conditions for column temperature, mobile phase pH and flow rate were optimized. A detailed validation of the method was performed for linearity, precision, accuracy, selectivity, limit of detection (LOD), limit of quantitation (LOQ), ruggedness and repeatability and reproducibility (R&R).     

光谱电化学法测定水果中抗坏血酸的研究

本文采用平行入射式光谱电化学装置，对水果中的抗坏血酸进行测定并寻找了最佳的测定条件。方法简便快捷，可消除背景干扰。线性范围１．０×１０＾－５－１．０×１０＾－４ｍｏｌ／Ｌ，检测下降为４．０×１０＾－６ｍｏｌ／Ｌ，回收率高，结果满意。     

2,8-二甲基-1,7-二氧杂螺[5,5]十一烷的合成

果蝇 ( Tephritidae)对水果生产有严重的危害 .热带果蝇寿命较长 ,具有很强的迁徙能力和繁殖能力 .因此开展果蝇生物防治和控制措施的相关研究具有重要的意义 [1,2 ] .Baker等 [3]发现性成熟的雌B.dorsalis果蝇 ,性腺分泌物中包含有螺环缩酮化合物 2 ,8-二甲基 - 1 ,7-二氧杂螺 [5 ,5 ]十一烷 ( 1 ) .Bactrocera Latifrons( Hendel)果蝇的雄性腺体分泌物中也存在螺环缩酮 1 [4 ] ,另外在 rove甲虫腹梢分泌物中也分离出 1 [5] ,螺环缩酮不仅作为性信息素组分存在于许多果蝇腺体中 ,而且作为结构单元存在于许多复杂的有强烈生理活性的天然…     

Rapid automated high performance liquid chromatography method for simultaneous determination of amino acids and biogenic amines in wine, fruit and honey

This paper reports a new, simple, rapid and economical method for routine determination of 24 amino acids and biogenic amines in grapes and wine. No sample clean-up is required and total run time including column re-equilibration is less than 40min. Following automated in-loop automated pre-column derivatisation with an o-phthaldialdehyde, N-acetyl-l-cysteine reagent, compounds were separated on a 3mm×25cm C(18) column using a binary mobile phase. The method was validated in the range 0.25-10mg/l; repeatability was less than 3% RSD and the intermediate precision ranged from 2 to 7% RSD. The method was shown to be linear by the 'lack of fit' test and the accuracy was between 97 and 101%. The LLOQ varied between 10μg/l for aspartic and glutamic acids, ethanolamine and GABA, and 100μg/l for tyrosine, phenylalanine, putrescine and cadaverine. The method was applied to grapes, white wine, red wine, honey and three species of physalis fruit. Grapes and physalis fruit were crushed, sieved, centrifuged and diluted 1/20 and 1/100, respectively, for analysis; wines and honeys were simply diluted 10-fold. It was shown using this method that the amino acid content of grapes was strongly correlated with berry volume, moderately correlated with sugar concentration and inversely correlated with total acidity.     

Flow-injection chemiluminescence determination of epinephrine in pharmaceutical preparations using raw apple juice as enzyme source

Raw apple juice exhibits the activity of polyphenol oxidase which can be employed for the determination of mono-, di- and polyhydric phenols. The chemiluminescence detection in the two-channel manifold was used to develop the new procedure for determination of epinephrine. Epinephrine can be determined by this method in pharmaceutical preparations in concentration ranges 1.0–10.0 and 10.0–25.0 mg l⁻¹, with a detection limit of 0.2 mg l⁻¹. Good selectivity against typical antioxidants and other coexisting substances was achieved. Relatively slow loss of the enzyme activity was observed during 1 week. The proposed method is very simple. Fresh juice solution from one apple can be prepared in 10 min and used for at least 8 h with excellent precision. Consumption of luminol solution was 0.15 ml min⁻¹. The throughput was 20 samples per hour.     

Lipids of Capsicum annuum Fruit Pulp

Lipids from fruit pulp of the sweet red pepper (Capsicum annuum, Solanaceae) were characterized. The principal components of the lipids from pepper fruit pulp were neutral lipids with predominance of triacylglycerines (55.8%). The polar lipids contained sulfoquinovosyldiacylglycerines and phosphotidylglycerines. The fatty-acid compositions of the neutral lipids, glycolipids, and phospholipids were determined.     

Turbidity of pulpy fruit juice: A key factor for predicting cross-flow microfiltration performance

To determine the technical and economic feasibility of cross-flow microfiltration on an industrial scale, the expected decline of permeation flux must be predicted taking into account the variability of juice's fouling potential. However, the main difficulty is finding representative parameters. Two semi-empirical models – gel polarisation and mechanistic – were used to fit experimental permeation flows using initial juice turbidity as surrogate for the volumetric concentration of particles in the feed juice. The experimental data of different banana, pineapple, and blackberry juices fitted well in both models. Although the mechanistic model more accurately estimated the permeation flux density, for practical application, the simpler polarisation model was preferred. Because this method uses a factor (i.e. turbidity) that reflects juice's fouling potential, it allows the optimisation of processing parameters and the prediction of permeation flux range in real industrial conditions.     

Tensile Properties and Morphology of Oil Palm Empty Fruit Bunch Regenerated Cellulose Biocomposite Films

The regenerated cellulose (RC)biocomposite films were prepared using casting method where oil palm empty fruit bunch (OPEFB) and microcrystalline cellulose (MCC) were dissolved in N-dimethylacetamide/lithium chloride (DMAc/LiCl)solution. The increasing of OPEFB contents up to 2 wt% increased the tensile strength and modulus of elasticity of RC biocomposite films while the elongation at break decreased. However, at 3 and 4 wt% of OPEFB content, the tensile strength and modulus of elasticity decreased with increases OPEFB content, but elongation at break increased. The increment of tensile strength and modulus of elasticity at 2 wt% is due to the OPEFB fiber that partially dissolved and dispersed with the OPEFB matrix. The morphology studies illustrate that at 2 wt% of OPEFB content of biocomposite films surface consists less voids and agglomerations than at 4 wt%. This can be considered the RC filler was partially dispersed with the RC matrix in the biocomposite films.     

液相色谱–串联质谱法测定水果及其制品中氯吡脲残留量

建立了液相色谱–三重四极杆串联质谱测定水果及其制品中氯吡脲的方法。样品经乙腈提取,氨基固相萃取小柱净化后,用ZORBAX Extend-C18柱(150 mm×2.1 mm,5μm)分离,以甲醇–水为流动相等度洗脱,采用多反应监测正离子模式检测,外标法定量。氯吡脲的质量浓度在4.0~200.0 ng/m L范围内线性良好,相关系数大于0.999,在5.0,10.0,20.0μg/kg 3个添加水平下,氯吡脲的平均加标回收率为86%~92%,测定结果的相对标准偏差为5.3%~7.6%(n=5),方法定量下限为2.0μg/kg。方法灵敏度高,操作简便,定量准确,可满足梨、柑桔、黄桃等水果及其罐头制品中氯吡脲残留的检测与确证需要。