Fish oil sensory properties can be predicted using key oxidative volatiles

The high level of PUFA in fish oil, primarily eicosapentaenoic acid (EPA) and DHA result in rapid oxidation of the oil. Current methods used to assess oxidation have little correlation with sensory properties of fish oils. Here we describe an alternative method using solid phase microextraction (SPME) combined with GC‐MS to monitor volatile oxidation products. Stepwise discriminant function analysis (DFA) was used to classify oils characterized as acceptable or unacceptable based on sensory analysis; a cross‐validated success rate of 100% was achieved with the function. The classification function was also successfully validated with tasted samples that were not used to create the method. A total of 14 variables, primarily aldehydes and ketones, were identified as significant discriminators in the classification function. This method will be useful as a quality control method for fish oil manufacturers. Practical applications: This paper describes an analytical method that can be used by fish oil manufacturers for quality control purposes. Solid phase microextraction and GC‐MS were used to monitor volatile oxidation products in fish oil. These data, combined with results of analyses by a sensory panel, were used to create a function that classified fish oil samples as acceptable or unacceptable. The volatile oxidation products used to in the function were primarily aldehydes and ketones. This method can be used by fish oil manufacturers as an alternative to expensive sensory panels.     

Effect of bacterial inoculum ratio in mixed culture for decolourization and detoxification of pulp paper mill effluent

BACKGROUND: Effluent released from industry is a mixture of various pollutants. For the degradation of complex pollutants, mixed bacterial cultures can be more effective than a single culture. This study investigated the balance of bacterial populations in a mixed culture for maximum reduction of pollutants. RESULTS: This study deals with the degradation and detoxification of pulp paper mill effluent (PPME) by three bacterial strains, i.e. Serratia marcescens, Serratia liquefaciens and Bacillus cereus in different ratios, and found that two ratios, 4:1:1 and 1:4:1, were effective for the degradation of PPME. These ratios reduced the various pollution parameters. Enzyme bioassay revealed that more enzyme was produced during degradation for the ratio 4:1:1. High performance liquid chromatography (HPLC) analysis showed that the ratio 4:1:1 degraded 95% of lignin and related compounds, and chlorophenols up to 98%, whereas ratio 1:4:1 reduced lignin by 84% and chlorophenols by 58% after 7 days incubation. Degradation products were confirmed by gas chromatography–mass spectrometry (GC‐MS) analysis. A seed germination bioassay on Phaseolous mungo L. revealed that toxicity was reduced by the ratio 4:1:1. CONCLUSION: Due to variable potential of different bacteria show variation in their growth pattern at any contaminated site. This study shows that an appropriate ratio of mixed cultures is required for maximum degradation and detoxification of PPME. Copyright © 2012 Society of Chemical Industry     

利用共存杂质分析甲基苯丙胺的合成信息

通过测定甲基苯丙胺样品中共存杂质的种类与含量,推测其合成途径及来源。将含MA样品用无水乙醇溶解,气相色谱-质谱法分析其组分,归-法计算相对百分含量。结果7个样品的甲基苯丙胺含量在9．81％-97．3％之间,其中3个样品含麻黄碱,含量在4．15％-5．52％;2个样品的共有成分为l-苯基-2-丙酮,含量分别为0．506％,0．696％;剩余2个样品既不含麻黄碱,也不含1-苯基-2-丙酮,甲基苯丙胺含量仅为23．5％和9．81％。推测7个样品中3批样品来源于麻黄碱合成途径,2批样品是苯丙酮合成途径,另2批样品由少量甲基苯丙胺混合其他成分配制而成。目前,麻黄碱仍是合成甲基苯丙胺的主要来源。     

AE．FFAP毛细管柱在小分子有机物定量分析中的应用

在GC6800A气相色谱仪上使用AE．FFAP毛细管柱和FID检测器研究了乙醚、乙醛、丙酮、乙醇和乙酸混合物的定量分析条件,重点讨论了柱温和柱前压对组份出峰时间、峰对称性及峰分离度的影响。结果表明,在实验得到的最优条件下,乙醇、乙醛、乙醚、乙酸和丙酮混合液有良好的分离效果,各组份的峰面积与浓度关系的线性相关系数大于0．99,满足定量分析的要求。     

Wheat Drought-Responsive Grain Proteome Analysis by Linear and Nonlinear 2-DE and MALDI-TOF Mass Spectrometry

A comparative proteomic analysis of drought-responsive proteins during grain development of two wheat varieties Kauz (strong resistance to drought stress) and Janz (sensitive to drought stress) was performed by using linear and nonlinear 2-DE and MALDI-TOF mass spectrometry technologies. Results revealed that the nonlinear 2-DE had much higher resolution than the linear 2-DE. A total of 153 differentially expressed protein spots were detected by both 2-DE maps, of which 122 protein spots were identified by MALDI-TOF and MALDI-TOF/TOF mass spectrometry. The identified differential proteins were mainly involved in carbohydrate metabolism (26%), detoxification and defense (23%), and storage proteins (17%). Some key proteins demonstrated significantly different expression patterns between the two varieties. In particular, catalase isozyme 1, WD40 repeat protein, LEA and alpha-amylase inhibitors displayed an upregulated expression pattern in Kauz, whereas they were downregulated or unchanged in Janz. Small and large subunit ADP glucose pyrophosphorylase, ascorbate peroxidase and G beta-like protein were all downregulated under drought stress in Janz, but had no expression changes in Kauz. Sucrose synthase and triticin precursor showed an upregulated expression pattern under water deficits in both varieties, but their upregulation levels were much higher in Kauz than in Janz. These differentially expressed proteins could be related to the biochemical pathways for stronger drought resistance of Kauz.     

毛细管柱气相色谱法测定食品中的甜蜜素

建立毛细管柱气相色谱测定食品中甜蜜素含量的方法,采用Rxi-5ms毛细管柱分离,FID检测器对甜蜜素进行测定。结果表明,在1～10mg范围内,线性回归方程为Y=0.0003X+0.1346,相关系数为0.9998,回收率为90.7%～99.0%,相对标准偏差为2.59%～3.69%。实验结果表明,用Rxi-5ms毛细管柱对甜蜜素进行分离,分离效果好,定量结果准确。     

便携式气相色谱仪分析低浓度苯系物的方法研究

目的:建立便携式色谱仪快速测定低浓度苯系物的方法;方法:在Tedlar气袋中制备目标化合物样品,采用便携式色谱仪内置恒流泵采样,预浓缩器预浓缩后热解析进样,毛细管柱分离,微氩离子检测器检测,确定保留时间和峰面积,保留时间定性,峰面积定量;结论:在本研究所选择的色谱条件下,苯系物具有良好的分离效果,高的准确度,高灵敏度、好重现性,能满足低浓度苯系物快速测定的要求。     

顶空毛细管气相色谱法测定二氟尼柳原料药中的残留溶剂

采用Agilent DB-624毛细管色谱柱（25 m×0.53 mm×3.0μm）,FID检测器,N,N-二甲基甲酰胺为溶剂,进行了顶空毛细管气相色谱法同时测定二氟尼柳原料药中二氯甲烷、苯及甲苯等3种残留溶剂的分析方法试验。结果表明,3种残留溶剂在各自的含量范围内呈良好的线性关系（相关系数0.994 5～0.997 5）,检测限分别为0.012 8、0.044 8、0.189 mg/L,平均添加回收率为90.6%～97.9%。所建方法简单、灵敏、可靠,适用于二氟尼柳原料药中残留溶剂的分析检测。     

2-甲氧基乙醇等4种化妆品禁用组分检测方法研究及应用

建立了化妆品中2-甲氧基乙醇（ME）、2-乙氧基乙醇（EE）、乙酸-2-甲氧乙酯（MEA）、2-（2-甲氧基乙氧基）乙醇（MEE）4种禁用组分的气相色谱测定法。样品采用无水乙醇提取,毛细管柱分离,气相色谱分析测定,阳性样品采用气相色谱/质谱联用法确证。4种目标组分能完全达到基线分离,在4～760μg/mL浓度范围内具有良好的线性关系,相关系数r均〉0.9999,回收率在96.0%～98.7%之间,相对标准偏差RSD在0.2%～4.4%之间。方法具有操作简单、定量准确、重现性好等特点,阳性样品进一步由气相色谱/质谱联用法确证,可避免假阳性误判,是一种具有实际应用价值且易于推广的方法。     

液相色谱-串联质谱法测定进出口人参、西洋参中蚜灭磷等6种农药

建立了人参、西洋参中凝胶色谱-固相萃取-液相色谱-串联质谱法测定蚜灭磷、吡虫啉、涕灭威、甲基内吸磷、甲硫威、辛硫磷6种农药的分析方法。样品经丙酮超声提取,凝胶色谱(GPC)净化后,固相萃取(SPE)净化,在HPLC/MS/MS多反应监测(MRM)模式下进行了定性和定量分析方法。在上述检测方法条件下,所测的6种农药的最低检出限为0.01 mg/kg,回收率范围为79.2%~107.3%,线性范围为0.01~0.2 mg/kg。