超高效液相色谱-串联质谱法测定牛奶中土霉素残留的不确定度评估

目的采用超高效液相色谱-串联质谱法对牛奶中土霉素残留的不确定度进行评估。方法测定牛奶中的土霉素,建立该方法测定牛奶中土霉素含量不确定度的数学模型,确定不确定度来源并对其评定。结果当牛奶中土霉素含量为0.049μg/g时,其扩展不确定度为0.0036μg/g(k=2)。其中,测量重复性和标准曲线对不确定度的影响最大。结论采用超高效液相色谱-串联质谱法测定牛奶中土霉素含量应严格控制实验条件,保证实验具有良好的重复性,另外还要保证标准曲线具有良好的线性。     

超高效液相色谱-串联质谱法测定牛奶中强力霉素残留的不确定度评估

目的采用超高效液相色谱-串联质谱法对牛奶中强力霉素残留的不确定度进行评估。方法测定牛奶中的强力霉素,建立该方法测定牛奶中强力霉素含量不确定度的数学模型,确定不确定度来源并对其评定。结果当牛奶中强力霉素含量为0.052μg/g时,其扩展不确定度为0.0056μg/g(k=2)。其中,测量重复性和标准曲线对不确定度的影响最大。结论通过采用超高效液相色谱-串联质谱法测定牛奶中强力霉素含量应严格控制实验条件,保证实验具有良好的重复性,另外还要保证标准曲线具有良好的线性。     

液相色谱-串联质谱法测定牛奶中地塞米松残留量的不确定度评定

目的评定液相色谱-串联质谱法测定牛奶中地塞米松残留量的不确定度。方法样品经过固相萃取柱净化处理后,经色谱柱分离,流动相等度洗脱,多反应监测模式进行检测。依据JJF10591.1-2012《测量不确定度评定与表示》,考察称量、标准溶液配制、标准曲线拟合、测量重复性等主要因素引入的不确定度,幵对不确定度的各分量进行计算和合成。结果当牛奶中地塞米松添加量为3.67μg/kg时,在95%的置信区间下,其扩展不确定度为0.198μg/kg(k=2)。评定结果表明,实验过程的不确定度主要来源于曲线拟合、测量的重复性。结论该斱法准确可靠,适用于液相色谱-串联质谱法测定牛奶中地塞米松残留量的不确定度评定,对检测结果准确度的提高具有指导意义。     

高效液相色谱-串联质谱法测定牛奶中3种磺胺类药物残留不确定度的评定

目的采用高效液相色谱-串联质谱法对牛奶中磺胺吡啶、磺胺噻唑和磺胺甲基异恶唑残留的不确定度进行评估。方法建立测定牛奶中磺胺吡啶、磺胺噻唑和磺胺甲基异恶唑含量不确定度的数学模型,确定不确定度来源并对其评定。结果当牛奶中磺胺吡啶含量为5.09μg/kg时,其扩展不确定度为0.62μg/kg(k=2);当牛奶中磺胺噻唑含量为8.62μg/kg时,其扩展不确定度为0.71μg/kg(k=2);当牛奶中磺胺甲基异恶唑含量为10.15μg/kg时,其扩展不确定度为0.81μg/kg(k=2)。其中,测量重复性和标准曲线对不确定度的影响最大。结论影响检测结果不确定度的主要因素为样品测量的重复性、标准曲线拟合和样品的前处理过程。     

同位素内标-超高效液相色谱-串联质谱法测定水产品中3种喹诺酮类兽药残留的不确定度评定

目的评定同位素内标-超高效液相色谱-串联质谱法测定水产品中3种喹诺酮类兽药残留的不确定度。方法按照农业部1077号公告-1—2008《水产品中17种磺胺类及15种喹诺酮类药物残留量的测定液相色谱-串联质谱法》测定水产品中恩诺沙星、环丙沙星和氧氟沙星3种喹诺酮类兽药残留。建立数学模型,分析和评定标准溶液配制、标准曲线拟合、样品称量、样品溶液制备和测量重复性等因素。结果水产品中恩诺沙星、环丙沙星和氧氟沙星残留量分别为18.8、9.04、6.56μg/kg时,其扩展不确定度分别为1.55、0.920、1.06μg/kg(k=2)。结论测量不确定度的主要来源是测量重复性、标准曲线的拟合与标准溶液的配制等过程,在实际检测过程中应加以控制。     

免疫亲和柱-高效液相色谱法测定牛奶中氯霉素和玉米赤霉醇及其类似物

建立免疫亲和柱同时净化-高效液相色谱法测定牛奶中氯霉素和玉米赤霉醇及其类似物（α-玉米赤霉醇、β-玉米赤霉醇、α-玉米赤霉烯醇、β-玉米赤霉烯醇、玉米赤霉酮和玉米赤霉烯酮）残留量的方法。样品经免疫亲和柱净化与富集后,用高效液相色谱-紫外检测器检测。采用Cloversil-C18反相柱分离,流动相为乙腈-甲醇-水溶液,检测波长为265 nm。结果表明,牛奶中添加氯霉素和玉米赤霉醇及其类似物的回收率在74%～101%,且相对标准偏差均小于7%。氯霉素的检出限为0.02 μg/L,玉米赤霉醇及其类似物的检出限分别为α-玉米赤霉醇0.03 μg/L、β-玉米赤霉醇0.03 μg/L、α-玉米赤霉烯醇0.03 μg/L、β-玉米赤霉烯醇0.03 μg/L、玉米赤霉酮0.04 μg/L和玉米赤霉烯酮0.05 μg/L。该方法灵敏度高、重复性好,提高了检测速率,可满足牛奶样品中痕量氯霉素和玉米赤霉醇及其类似物残留的测定。     

高效液相色谱-串联质谱法测定猪肉中氯丙嗪残留量的不确定度评定

目的 评定高效液相色谱-串联质谱法测定猪肉中氯丙嗪残留量的不确定度。方法 参考 GB/T 20763-2006《猪肾和肌肉组织中乙酰丙嗪、氯丙嗪、氟哌啶醇、丙酰二甲氨基丙吩噻嗪、甲苯噻嗪、阿扎哌隆、阿扎哌醇、咔唑心安残留量的测定 液相色谱-串联质谱法》和JJF 1059.1-2012《测量不确定度评定与表示》中的规定和要求,分析氯丙嗪在测定过程中的各种不确定度的来源。结果 当猪肉中氯丙嗪残留量为8.9 μg/kg时,其扩展不确定度为1.496μg/kg (k=2)。结论 不确定度的影响因素主要是样品前处理过程、标准溶液的配制与稀释和标准曲线拟合过程。     

液相色谱-串联质谱法测定牛奶中氯霉素残留量的不确定度评定

目的采用液相色谱-串联质谱法对牛奶中氯霉素的残留量进行不确定度评定。方法根据GB29688-2013《牛奶中氯霉素残留量的测定液相色谱-串联质谱法》建立数学模型,根据JJF 1059.1-2012《测量不确定度的评定与表示》对测量结果的各不确定度来源进行分析和量化。结果本方法的不确定度主要来自于标准曲线的建立及测定结果重复性。当氯霉素的添加水平为0.1064 ng/g时,氯霉素的结果可表示为0.1064±0.0457 ng/g(k=2)。结论该评定方法清晰合理,简便准确,可适合液相色谱-串联质谱法对牛奶中氯霉素的残留量测定的不确定度评定。     

同位素稀释-超高效液相色谱-串联质谱法测定水产品中孔雀石绿、结晶紫及其代谢物残留量的不确定度评定

建立同位素稀释-超高效液相色谱-串联质谱法同时测定水产品中孔雀石绿、结晶紫、隐性孔雀石绿、隐性结晶紫残留的不确定度评定方法,依据GB/T 19857-2005《水产品中孔雀石绿和结晶紫残留量的测定》,建立数学模型,通过不确定度来源分析建立不确定度评价方法。结果表明:标准溶液的配制和标准曲线拟合引入的不确定度最大,而同位素稀释法可以减小前处理过程和基质效应引入的不确定度。水产品中孔雀石绿残留量为14.26 μg/kg时,其扩展不确定度为1.35 μg/kg(k=2);结晶紫残留量为15.28 μg/kg时,其扩展不确定度为1.29 μg/kg(k=2);隐性孔雀石绿残留量为14.47 μg/kg时,其扩展不确定度为1.21 μg/kg(k=2);隐性结晶紫残留量为14.69 μg/kg时,其扩展不确定度为1.24 μg/kg(k=2)。     

免疫亲和净化-超高效液相色谱-串联质谱法测定食品中玉米赤霉烯酮类真菌毒素

建立食品中6种玉米赤霉烯酮类(α-玉米赤霉醇、β-玉米赤霉醇、α-玉米赤霉烯醇、β-玉米赤霉烯醇、玉米赤霉酮、玉米赤霉烯酮)真菌毒素的免疫亲和净化-超高效液相色谱-串联质谱检测的实验方法。样品经80%乙腈溶液提取,通过免疫亲和柱净化富集,用2 mL乙腈洗脱,氮吹至近干,0.5 mL 50%乙腈溶液复溶,采用超高效液相色谱-串联质谱进行测定。在ACQUITY UPLC HSS T3反相柱上分离,梯度洗脱,流动相为乙腈和水,质谱采集模式为电喷雾负离子多反应监测模式。6种目标物的线性范围为0.1~100μg/L,相关系数(R~2)均大于0.992,检出限为0.05μg/kg,定量限为0.2μg/kg,3个不同水平的加标平均回收率为73.0%~119.1%,相对标准偏差不大于10%。该方法具有操作简单、重复性好、灵敏度高、杂质干扰小等特点,可以用于食品中玉米赤霉烯酮类真菌毒素的检测。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Review of techniques to manufacture micro-hydrogel particles for the food industry and their applications

Microgels are ‘soft’ microscopic cross-linked polymeric particles that are being increasingly exploited in a variety of industries for rheology control, encapsulation and targeted delivery. They are valued because of the ability to tune their functionality to address specific applications in oil recovery, coatings, drug delivery, cosmetics, personal care and foods. Food microgels are typically biopolymer hydrogels in the form of microspheres, nanospheres (also called nanogels), spheroids and fibres. The utilisation of engineered microgels in foods has so far been limited, despite their great potential to address several needs in the food industry, including: satiety control, encapsulation of phytonutrients and prebiotics, texture control for healthier food formulations (e.g. reduced fat products), and targeting delivery to specific areas in the digestive tract. We review the scientific and patent literature on the utilisation and manufacturing methods for producing microgels with an emphasis on micro-hydrogels for food applications.     

12—A CRITIQUE OF SOME HYPOTHESES RELATING TO THE HETEROGENEITY OF THE HIGH-SULPHUR PROTEINS OF WOOL

Joubert and Burns prepared a large number of fractions from the high-sulphur proteins of wool and estimated their molecular weights and amino-acid compositions. Their data have been re-examined in order to look for statistically significant interrelations between amino acids and between the proportion of various amino acids and molecular weight. Statistical analysis of the data is also used to examine the credibility of some hypotheses concerning the mechanism of keratin biosynthesis and to provide further evidence for the existence of families of proteins within the high-sulphur fractions of wool.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of     

The Latest Data about Development of Chinese Printing Industry in 2013

In the 2014 China（Shanghai）International Printing Week,Director Wang Yanbin released the latest data about development of Chinese printing industry in 2013.According to statistics,in 2013,the total output value of Chinese printing industry exceeded 1trillion Yuan for the first time,reaching 1.03985 trillion Yuan.There were 105,000 printing enterprises in China,employees were 3.415 million.The total asset was 1.06247 trillion Yuan;     

The State Council Issued "Directory of Government Approved Investment Projects(2013 Edition)"

正On December 2nd,2013,the State Council issued the notification of"Directory of Government Approved Investment Projects(2013 Edition)"(hereafter referred to as"notification").It is pointed out in the"notification"that in order to further deepen reforms in investment systems and administrative examination and approval systems,simplify administrative procedures and delegate powers to lower levels,earnestly     

Top Ten News of China's Paper Industry 2013

On December 24th, 2013, the meeting on the selection of top 10 news of China＇s paper industry 2013 sponsored by 〈China Paper Newsletters〉 was held in Beijing. The yearly selection of the top l0 news, which began in 2000, has become a brand activity widely recognized in the industry thanks to the support from the authorities at all levels and public participation.     

National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the "13~(th) Five-Year Plan"

In Apri Commi major p Plan＂ （h 2014, the National Development and Reform ssion issued an announcement for selection of reliminary research projects for the ＂13th Five-Year ereafter referred to as ＂The Announcement＂）     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the latest scientific     

China textile machinery: taking off in progress

正Among the 1600 exhibitors who take apart in the ITMA ASIA+CITME2014 2/3 are Chinese manufactures.If the numerous figures failed to attract your attention,the increase of quality should draw your focus.To adopt the demand of developing textile machine market,domestic textile machinery enterprises now follow the slogan of"technology drives development"to enhance product competitiveness.Our domestic sellers will showcase product ranging from spinning,weaving,dyeing and printing,