Surveillance study of a number of synthetic and natural growth promoters in bovine muscle samples using liquid chromatography-tandem mass spectrometry

A simple, new method permitting the simultaneous determination and confirmation of trace residues of 24 different growth promoters and metabolites using liquid chromatography-mass spectrometry was developed and validated. The compounds were extracted from bovine tissue using acetonitrile; sodium sulphate was also added at this stage to aid with purification. The resulting mixture was then evaporated to approximately 1?ml and subsequently centrifuged at high speed and an aliquot injected onto the LC-MS/MS system. The calculated CCα values ranged between 0.11 and 0.46?µg?kg^?1; calculated CCβ were in the range 0.19–0.79?µg?kg^?1. Accuracy, measurement of uncertainty, repeatability and linearity were also determined for each analyte. The analytical method was applied to a number of bovine tissue samples imported into Ireland from third countries. Levels of progesterone were found in a number of samples at concentrations ranging between 0.28 and 30.30?µg?kg^?1. Levels of alpha- and beta-testosterone were also found in a number of samples at concentrations ranging between 0.22 and 8.63?µg?kg^?1 and between 0.16 and 2.08?µg?kg^?1 respectively.     

Surveillance study of a number of synthetic and natural growth promoters in bovine muscle samples using liquid chromatography-tandem mass spectrometry

A simple, new method permitting the simultaneous determination and confirmation of trace residues of 24 different growth promoters and metabolites using liquid chromatography-mass spectrometry was developed and validated. The compounds were extracted from bovine tissue using acetonitrile; sodium sulphate was also added at this stage to aid with purification. The resulting mixture was then evaporated to approximately 1 ml and subsequently centrifuged at high speed and an aliquot injected onto the LC-MS/MS system. The calculated CCα values ranged between 0.11 and 0.46 μg kg(-1); calculated CCβ were in the range 0.19-0.79 μg kg(-1). Accuracy, measurement of uncertainty, repeatability and linearity were also determined for each analyte. The analytical method was applied to a number of bovine tissue samples imported into Ireland from third countries. Levels of progesterone were found in a number of samples at concentrations ranging between 0.28 and 30.30 μg kg(-1). Levels of alpha- and beta-testosterone were also found in a number of samples at concentrations ranging between 0.22 and 8.63 μg kg(-1) and between 0.16 and 2.08 μg kg(-1) respectively.     

雪糕中合成色素的测定

分别采用碱性硫酸铜和乙酸锌-亚铁氰化钾作为沉淀剂对雪糕样品进行预处理,并按照GB/T5009.35-2003第一法中的聚酰胺吸附法对样液中的色素进行提取,用高效液相色谱法进行合成色素含量的测定.结果表明,采用沉淀剂对样品进行预处理,可降低雪糕浆料的粘稠度,有利于色素的提取.对于四种常用合成色素柠檬黄、胭脂红、日落黄、亮蓝,以碱性硫酸铜作为沉淀剂,加标回收率为72.04%～82.64%,相对标准偏差为1.48%～3.50%;以乙酸锌-亚铁氰化钾作为沉淀剂,加标回收率为81.62%～95.73%,相对标准偏差为1.46%～3.19%.采用乙酸锌-亚铁氰化钾进行样品预处理的方法准确度和精密度良好,可作为高效液相色谱法测定雪糕中合成色素的样品预处理方法.     

白酒中人工合成甘油及环氧氯丙烷的测定

目的 建立一种白酒中环氧氯丙烷的完善、准确检测方法 ,幵作为白酒添加人工合成甘油的辅助判定手段。方法 白酒中的环氧氯丙烷经过二氯甲烷萃取、浓缩和高弹石英毛细管柱分离,利用气相色谱-质谱联用仪(gas chromatography-mass spectrometer,GC-MS)迚行测定,幵以灵敏度最高的离子对迚行定量分析。结果 该方法相对标准偏差(relative standard deviation, RSD)10%,加标回收率为75.5%～89.0%,最低检出限为1.0μg/L。结论 该方法灵敏度高,准确性好,适用于白酒中环氧氯丙烷的测定。     

人造金刚石晶体的生长速率

文章讨论了影响人造金刚石生长速率的因素,指出生长速率低是生产大颗粒人造金刚石单晶的瓶颈。作者预测：在保证金刚石晶体质量的同时,提高其生长速率的可能性是存在的。     

金刚石生长的驱动力

籽晶方法生长金刚石采用温度梯度技术,金刚石晶体生长驱动力来源于腔体内构造的温度梯度。工业上采用自发成核生长金刚石技术,金刚石生长的驱动力来源于金刚石晶体与石墨温度差。     

Interaction between lactose levels and antimicrobial growth promoters on growth performance of weanling pigs

In experiment 1, 224 pigs (initially 8.85 kg and 28 ± 2 days of age) were used in a 2 × 2 factorial arrangement of treatments to investigate the interaction between lactofeed (LF70) (860 g kg^?1 whey permeate, 140 g kg^?1 soya bean meal) level (175 g kg^?1 and 350 g kg^?1) and avilamycin (0 and 40 mg kg^?1) inclusion in piglet starter diets. Pigs were fed starter diets from day 0 to day 22 and a transition diet was fed from day 23 to day 39. The inclusion level of LF70 in the transition diet was 75 g kg^?1 and 150 g kg^?1. Pigs fed 350 g kg^?1 LF70 had a higher daily gain (ADG) (p < 0.01) and an improved feed conversion ratio (FCR) (p < 0.05) during the starter period than the pigs fed 175 g kg^?1 LF70. Pigs fed medicated diets had a higher ADG (p < 0.05) and an improved FCR (p < 0.05) than the non‐medicated fed pigs during the starter period. There was an increase in feed intake (AFI) (p < 0.05) during the transition period with increasing levels of LF70. There was an improvement in FCR during the transition period with the inclusion of avilamycin (p < 0.01). There was a significant interaction (p < 0.01) between LF70 and avilamycin for ADG during the transition period. The inclusion of avilamycin at 175 g kg^?1 LF70 inclusion had no effect (p > 0.05) on ADG. However at 350 g kg^?1 LF70 inclusion the pigs offered medicated diets had a higher ADG (p < 0.001) compared with non‐medicated diets. In experiment 2, 224 pigs (initially 8.85 kg and 28 ± 2 days of age) were used in a 2 × 2 factorial to investigate the interaction between LF70 level (175 g kg^?1 and 350 g kg^?1) and zinc oxide (ZnO) (0 and 3.1 g kg^?1) inclusion in piglet starter diets. The inclusion level of LF70 in the transition diet was 75 g kg^?1 and 150 g kg^?1 and of ZnO was 2 g kg^?1. There was a significant increase (p < 0.05) in ADG with increasing levels of LF70 during the starter period. The inclusion of ZnO during the starter period resulted in an increase in ADG (p < 0.001) and FCR (p < 0.05) compared with no ZnO inclusion. Neither the inclusion of zinc oxide not of LF70 had an effect (p > 0.05) on performance during the transition period. In conclusion the supplementation of starter diets with increasing levels of LF70, ZnO and avilamycin resulted in increased ADG and improved FCR. Copyright © 2004 Society of Chemical Industry     

固相萃取-高效液相色谱法测定肉制品中合成着色剂的含量

建立测定肉制品中合成着色剂苋菜红、胭脂红和诱惑红含量的固相萃取-高效液相色谱法。方法 以氨水-90%乙醇(1+99,V/V)溶液为提取液,超声提取肉制品样品中的着色剂,经PLS固相萃取柱净化,色谱柱为Dikma Spursil C18(4.6mm×150mm,5μm)。以乙腈-0.05mol/L乙酸铵溶液为流动相进行梯度洗脱色谱分离,流速1.0ml/min,柱温30℃,进样量10μl,检测波长200～700nm。结果 在0.5～25.0μg/ml,苋菜红、胭脂红和诱惑红的峰面积与其相应浓度呈良好相关性,相关系数r分别为0.9996、0.9997和0.9993,方法加标回收率为94.2%～99.1%。结论 本方法准确度高,具有良好的重现性和精密度,能快速对肉制品中3种合成着色剂进行定量检测,满足国家限量标准的要求。     

拟除虫菊酯类农药残留检测技术的研究进展

近年来,随着拟除虫菊酯类农药的广泛使用,其残留问题也日益突出。拟除虫菊酯类农药的大量使用给我国的出口贸易以及人类健康带来重大隐患。加强拟除虫菊酯类农药残留检测技术的研究是解决其残留超标问题的重要步骤。文中主要对用于拟除虫菊酯农药残留检测的气相色谱法、液相色谱法、质谱技术、分光光度法、生物传感器等技术进行了综述,并对其发展趋势进行了展望。     

高效液相色谱法同时测定食品中7种合成色素

建立了食品中柠檬黄、新红、苋菜红、胭脂红、日落黄、诱惑红和赤藓红7种合成色素的高效液相色谱分析法。样品经含有1%氨水的70%乙醇提取,聚酰胺粉末吸附、净化和富集后进行HPLC分析。采用Eclipse plus C18（250 mm×4.6 mn,5μm）色谱柱为分析柱,0.02 mmol/L乙酸铵水溶液-甲醇为流动相梯度洗脱,二极管阵检测器检测,外标法定量。结果表明：7种色素在0.5~20.0mg/L范围内有良好的线性关系,方法的检出限（S/N=3）分别为0.05、0.05、0.03、0.03、0.05、0.06和0.07 mg/kg,加标回收率为82.83%~105.39%,相对标准偏差不大于8.40%。     

Listeria growth under diffusional limitations in synthetic meats

Physicochemical properties of meat products make them susceptible to contamination by several pathogens such as Listeria monocytogenes . As reference of L. monocytogenes behaviour, the evolution of Listeria innocua growth was monitored at different positions within a κ-carrageenan synthetic meat and visualised by scanning electron microscopy (SEM). Microbial growth was also determined in a liquid medium, prepared with the same nutrients as the solid phase, and the effect of oxygen concentration, a fundamental parameter in meat preservation, was studied. To simulate microbial behaviour in the solid, results of kinetics in broth were incorporated to a diffusion-reaction model that considers growth kinetics as a function of the local oxygen concentration. Data from the model have been then discussed, taking into account experimental data and SEM observations. This model, useful for food safety purposes, has been shown to provide a reasonably good simulation of experimental data in the structured synthetic meat.     

Determination of synthetic food dyes in food by capillary electrophoresis

A method for the determination of 12 synthetic food dyes (Amaranth, Erythrosine, Allura Red AC, New Coccine, Phloxine, Rose Bengal, Acid Red, Tartrazine, Sunset Yellow FCF, Fast Green FCF, Brilliant Blue FCF, Indigo Carmine) in food was developed using capillary electrophoresis (CE) with photodiode array detection. The dyes were extracted with water and 0.5% ammonia-ethanol (1:1) mixture, and cleaned up using solid-phase extraction (Sep-Pak Plus tC18). The dyes were eluted with methanol from the cartridge. The dyes were separated by CE on a bubble cell fused-silica capillary (72 cm to the detector, 75 microm i.d.) using 20% acetonitrile in a mixture of 10 mmol/L potassium phosphate, monobasic and 5 mmol/L sodium carbonate (pH 10.0) as the running buffer. Identifications of the dyes were performed on the basis of the migration time and the absorbance spectrum of each peak. The coefficients of variation of the migration times and the peak areas were 0.28-0.62% and 1.84-4.30%, respectively (n = 5). The identification limits using the absorbance spectra of the dyes were 10 microg/mL for Brilliant Blue FCF and Fast Green FCF, and 5 microg/mL for the other 10 dyes. The recoveries of the 12 dyes from pickles, soft drinks and candies at the level of 10 microg/g were 70.0-101.5%. The method was applied to the analysis of dyes in foods. The dyes detected by CE were in agreement with those detected by paper chromatography.     

高效液相色谱法同时测定葡萄酒中9种人工合成色素

建立了葡萄酒中9种人工合成色素的高效液相色谱检测法。方法采用Zorbax SB-C18色谱柱分离,以25mmol/L乙酸铵水溶液-甲醇为流动相进行梯度洗脱。采用二极管阵列检测器,峰保留时间和峰扫描光谱纯度对照两种方式对样品峰进行定性,利用色素最大可见吸收波长测定各色素以消除杂质干扰。该方法的线性范围0.50mg/L~100mg/L,加标回收率95.8%~100.4%,相对标准偏差（RSD）为0.89%~1.26%。     

Investigations of Saccharothrix algeriensis growth on synthetic media

Development of bacterial resistance to antibiotics has lead to investigations of rare bacteria, which produce new bioactive molecules. Saccharothrix algriensis has been isolated from the desert Maghreb. It produces dithiolopyrrolones, some of which were newly identified. In order to optimize and control production of dithiolopyrrolones, investigation regarding microorganism metabolism was required. Growth on semisynthetic medium containing 2 g x l(-1) of yeast extract was complicated because it was performed on several substrates. Moreover, because development of this bacterium on minimum medium was difficult, its composition was optimized by screening of different compounds led by yeast extract. Uracil added to the minimum medium allowed a maximum biomass production of 1.35 g x l(-1) compared to 0.32 g x l(-1) without uracil. Moreover, nonpolar amino acids and trace metal elements stimulated Saccharothrix algeriensis growth.     

高效液相色谱法测定肉类与肉制品中添加的人工合成着色剂

人工合成着色剂广泛使用于各种食品,但是《食品添加剂使用卫生标准》规定人工合成着色剂应用的品种类别不包括熟肉类食品(主要为热处理加工后的肉类食品),这些人工合成着色剂着色力强,能够使食品保持色泽鲜艳,但不能提供人体所需的任何营养物质,且一些合成着色剂还会危害人体的健康,食品中加入人工合成着色剂可以达到降低成本以及欺瞒消费者的效果。国家标准采用的高效液相色谱法,准确度高、方法灵敏、重现性好,但是对熟肉类制品中的人工合成着色剂没有提出有效的方法,由于样品的差异,需要对处理方法进行改进才能应用于熟肉类样品,实验证明,文中采用的高效液相色谱法适合6种合成着色剂的测定,回收率良好,可以配合对餐饮行业的监督。     

Determination of synthetic phenolic antioxidants in food items using reversed-phase HPLC

A HPLC with gradient elution method for the determination of the synthetic phenolic antioxidants (SPAs) propyl gallate (PG), tertiary butyl hydroquinone (TBHQ), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) in food items is described. A C18 column served as the stationary phase; the gradient elution was formed by acetonitrile and water:acetic acid (1%). The UV detector was set at 280 nm. Under the recommended conditions, separation of the four SPAs was achieved in less than 8 min. Analytical characteristics of the HPLC method such as limit of detection, linear range, and reproducibility were evaluated. Extraction parameters were optimized for the recoveries of the SPAs in different types of food items (cooking oil, margarine and butter, and cheese). Before the HPLC separation, the SPAs were extracted with methanol/acetonitrile (1:1, v/v) and were subjected to vortex/ultrasonic treatment. The extracts were next kept in a freezer (∼2 h) to precipitate co-extracted components. Recoveries of the SPAs when spiked to cooking oil, margarine, butter and cheese at 50 and 200 mg l⁻¹ were in the ranges 93.3–108.3% for PG, 85.3–108.3% for TBHQ, 96.7–101.2% for BHA and 73.9–94.6% for BHT. The method was applied to the determination of SPAs in 38 food items (16 cooking oils, ten margarine, six butter and six cheese samples). The levels of SPAs in positive samples are all below the legal limits of Malaysia.     

Simultaneous immunochemical detection of four banned antibiotic growth promoters in raw and cooked poultry tissue

Spiramycin, tylosin, bacitracin and virginiamycin are among a group of antibiotic growth promoters that have been banned in the European Union since the 1999 Council. This was due to concerns over the development of resistant bacteria emerging between humans and animals with the threat of antibiotics no longer being able to be used effectively to treat human infections. A sensitive and fast immunochemical method is presented for the determination of these four antibiotic growth promoters simultaneously in poultry tissue. The method employs methanol extraction followed by sample clean-up by solid-phase extraction (SPE) with determination by enzyme-linked immunoabsorbant assay (ELISA). The limit of detection (LOD) was less than 1 ng g^?1 and the detection capability (CCβ) was 3 ng g^?1 or less for all four antibiotic growth promoters. Validation was completed with both raw and cooked chicken, therefore either matrix could be used for the monitoring of these banned drugs. In a feeding trial no residues of either bacitracin or virginiamycin were found in medicated birds even without a withdrawal period. In the case of tylosin and spiramycin much higher residues level were detected immunochemically than was the case by mass spectrometry.     

毛针织服装风格综合评价中主因子的确定

介绍了主因子分析法中主因子的含义、主因子与毛针织服装风格之间的关系以及通过计算每个因子的方差和累加方差贡献率的大小确定主因子的依据和方法.通过对主因子的分析研究,得出了毛针织服装的基本风格可归纳为5种,用5个基本因子,即变形因子、弹性因子、膨松因子、粗糙因子和刚柔因子来表示.这些因子之间的相关性很小,这是主观评价所不能达到的.这些主因子的确定,为毛针织服装风格客观综合评价的研究奠定了基础.     

Effect of synthetic human pancreatic growth hormone-releasing factors on plasma growth hormone concentrations in lactating cows

Two fragments of human pancreatic growth hormone-releasing factor, hpGRF-(1-24)-NH2 and hpGRF(1-29)-NH2, were administered to lactating dairy cows in separate experiments. Each experiment involved a 4 X 4 Latin square with treatments being intravenous administration of saline (controls) or three doses of releasing factor (500, 1000, and 2000 micrograms). Administration of the 24-amino acid fragment increased plasma growth hormone concentration from baseline 3 ng/ml to peak 14 ng/ml within 10 min. Growth hormone concentrations returned to baseline by 60 min post treatment. The 29-amino acid fragment resulted in greater responses in both peak concentration (30 ng/ml) and persistency (greater than 240 min). Relationships between dose of releasing factor and response in growth hormone release (as measured by area under the response curve) were not consistent in most cows. Responses of concentrations of growth hormone in blood plasma that result from intravenous injection of up to 2000 micrograms of growth hormone-releasing factor (1-29) would not be sufficient to increase milk yield of cows.