Determination of aryloxyphenoxypropanoic acid derivatives in crops treated with herbicidal sprays

Summary A reproducible and sensitive gas Chromatographic method has been developed for the trace analysis of fluazifop-butyl, haloxyfop-ethoxyethyl and quizalofop-ethyl as well as their main metabolites (corresponding acids analysed after conversion to methyl esters) in some fruits and vegetables treated with herbicidal sprays. Comparable detection limits (0.01 mg/kg) were achieved when mass fragmentography and/or the electron capture detector were employed. However, in the latter case, bromination of fluazifop esters had to be carried out prior to GC analysis. By means of the nitrogen-phosphorus detector, determination of residues at a level of 0.05 mg/kg was possible. The residue values found in strawberries, cabbages, cauliflowers and carrots were used to discuss the degree of metabolic hydrolysis of parent esters, i.e. active ingredients of herbicides.

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Bestimmung von Aryloxyphenoxypropionsäure-Derivaten in mit Herbicidsprays behandelten Produkten

Zusammenfassung Es wurde eine gaschromatographische Methode zur quantitativen und selektiven Bestimmung von Fluazifop-butyl, Haloxyfop-ethoxyethyl und Quizalofop-ethyl sowie von ihren Hauptmetaboliten (den entsprechenden Säuren, die zu Methylestern umgesetzt werden müssen) in mit Herbiciden behandelten Obst- und Gemüseproben entwickelt. Eine Nachweisgrenze von 0,01 mg/kg wurde durch Elektroneneinfanggaschromatographie oder durch Massenfragmentographie erzielt. Um die gleiche Empfindlichkeit des EC-Detektors bei Fluazifop zu erreichen, wurden die beiden Ester mit Brom umgesetzt. Mit Hilfe des NP-Detektors konnte eine Nachweisgrenze von 0,05 mg/kg erreicht werden. Die festgestellten Rückstandsgehalte in Erdbeeren, Kohl, Blumenkohl und Möhren wurden gleichzeitig zur Beurteilung der metabolischen Hydrolyse der diskutierten Ester (der Wirkstoffe der Herbicide) herangezogen.

     

离子对色谱-ELSD检测麦类中植酸的方法研究

建立了应用离子对色谱-蒸发光散射检测(IPC-ELSD)麦类作物中植酸含量的方法,并结合电喷雾质谱(ESI-MS)分析鉴定了各组分。色谱条件:C18色谱柱(5μm,4.6 mm×150 mm);流动相:甲醇-水(体积比60∶40,含0.4%正戊胺,甲酸调节p H为4.5);流速1.0 m L/min;柱温35℃。结果表明,植酸含量在0.25~5.0 mg/m L范围内线性关系良好(R2=0.999 1),检测限为40μg/m L,平均回收率为90.44%,相对标准偏差为3.13%。该方法快速、准确,适用于麦类中植酸含量的测定。     

全自动固相萃取-气相色谱-质谱联用法测定油料 作物中2,4-二氯苯氧乙酸和2,4,5-三氯苯氧乙酸的残留量

目的建立全自动固相萃取-气相色谱-质谱联用法测定花生、大豆和芝麻3种油料作物中2,4-二氯苯氧乙酸和2,4,5-三氯苯氧乙酸的分析方法。方法样品经过二氯甲烷提取,衍生化反应,全自动固相萃取仪净化,DB-5MS毛细管色谱柱分离,选择离子扫描模式检测,外标法定量。结果 2种农药在线性范围内具有良好的线性关系,相关系数r≥0.999,定量限均低于0.010 mg/kg,添加的平均回收率在73.6%~100.8%之间,相对标准偏差在3.31%~7.68%之间。结论建立的方法样品前处理简单,净化过程实现了自动化操作,大大提高了工作效率。该方法灵敏度高、回收率好,适用于油料作物中2种农药的同时检测。     

Determination of acid phosphatase activity in heat treated milks by the Fluorophos Test System

The Fluorophos Test System® for measurement of acid phosphatase in fruit juices was used to determine the survival of acid phosphatase in heat treated cows' milk. The method was found to be applicable to milk, with reproducibility improved by use of a vortex mixer. It was sufficiently sensitive to provide a quantitative measure of the activity surviving heat treatments from 75 to 88° C for 15 seconds and would thus provide a rapid method for checking more severe heat treatments_ for instance, those used to enhance the destruction of Mycobacterium paratuberculosis.     

Amino acid content of seeds of orchard crops

In agreement with previous research it has been found that the most prominent amino acid in seeds of 12 orchard crops was glutamic acid followed by arginine and aspartic acid while the least represented in all cases was methionine. Although correlation figures have not been worked out the results show that the percentage lysine content was highest in the group where the percentage protein content was lowest.     

Preservation of moist hay in miniature bales treated with propionic acid

In 2 experiments, propionic acid was applied by hand-sprayer to partly dried hay which was made into miniature bales of about 1 kg. In an experiment in which the hay moisture content was 51%, acid was applied at 0%, 1%, 2%, 4%, 6% and 8% by weight. Bales with less than 4% acid showed severe heating, moulding, and losses of dry matter and nutrient content within a few weeks. Bales with 4% acid or more were still well preserved after 3 months. In a second experiment hays of 32% and 41% moisture showed moulding at 0.5% and 1.0% acid respectively, but slight or no moulding at 1.0% and 1.5% acid. At 48%, 59% and 76% moistures the lowest acid levels used, 2%, 3% and 3.5% respectively, all prevented moulding.It was concluded that acid treatments of 1%, 1%–1.5%, and 2% for hays of 30%, 40% and 50% moisture respectively were on the margin between being effective and ineffective in the preservation of hay stored under experimental conditions.     

The effect of lactic acid sprays on the keeping qualities of meat during storage

Spraying the meat surface of skinned cow heads with 1% v/v lactic acid resulted in significant reduction in total viable counts of bacteria at storage temperatures of 4, 15 and 20 degrees C. The number of coliform bacteria was also reduced at all three temperatures but the reductions were not statistically significant on most occasions. However, after five and two days at 15 degrees C and 20 degrees C, respectively, when the initial effect of acid appeared to be lost, the number of coliforms on sprayed heads exceeded those on unsprayed heads. The shelf lives of all sprayed heads were observed to have been extended for about three days at 4 degrees C and one day for both 15 degrees C and 20 degrees C.     

壳聚糖及其衍生物整理精纺呢绒的抗菌性

讨论了柠檬酸和壳聚糖及其衍生物对精纺呢绒整理的抗菌效果,运用扫描电镜照片和傅里叶变换红外光谱图对壳聚糖及其衍生物与羊毛的交联机理和抗菌机理进行了探讨。结果表明,经整理的精纺呢绒洗涤20次后,对金黄色葡萄球菌和大肠杆菌仍保持较高的抗菌性。     

气相色谱法测定烟草中的绿原酸

以正己烷及甲醇水溶液为萃取剂依次为烟草进行萃取,将萃取物烷基化后进行气相色谱分析,并对其中的主要成分绿原酸进行了定量分析。实验结果表明,本方法灵敏度高,重现性好。     

15种粮食中部分金属元素含量的检测分析

采用湿法一次消解15种粮食样品,分别利用石墨炉原子吸收光谱法和原子荧光光谱法测定了样品中镉、铅、铜、铬、锌、铁、锰、砷、汞、硒的含量.在选定的试验条件下,方法的回收率在89.1％～102.0％,相对标准偏差均小于5％,检出限介于0.005 0～0.92 ng/ml.     

Determination of ammonium in Kjeldahl digests of crops by an automated procedure

An automated technique has been developed for estimating NH₄⁺ in Kjeldahl digests of crops, using the salicylate-dichloroisocyanurate reaction in the presence of nitroprusside. The method gives reproducible results in close agreement with those from conventional distillation and titration, and there is a marked improvement in output.     

QuEChERS-高效液相色谱法检测油料作物中氟磺胺草醚残留量

目的建立QuEChERS-高效液相色谱联用技术检测油菜籽、大豆、花生中氟磺胺草醚残留量的方法。方法样品用1%甲酸水溶液和乙腈提取,经N-丙基乙二胺粉末净化,色谱柱分离,以0.1%甲酸水溶液和乙腈为流动相进行洗脱,二极管阵列检测器检测,检测波长295 nm。结合保留时间和紫外光谱进行定性分析,峰面积进行定量分析。结果氟磺胺草醚在0.5～100μg/mL范围内线性良好,相关系数(r~2)为0.9999,方法检出限为0.021mg/kg;在油菜籽、大豆、花生中3个添加水平的平均回收率为89.9%～102.3%,相对标准偏差为2.5%～7.2%。结论该方法简便、快捷、节约溶剂,适用于油料作物中检测氟磺胺草醚残留量。     

RP-HPLC法测定食用动物油脂中苯甲酸与山梨酸的含量

建立测定食用动物油脂中苯甲酸与山梨酸含量的反相高效液相色谱法。采用反相高效液相色谱法,色谱柱为Wondasil C18(4.6mm×250mm,5μm),以甲醇-0.02mol/L乙酸铵溶液(5∶95)为流动相,检测波长为230nm,测定食用动物油脂中苯甲酸与山梨酸的含量。柱温为30℃,流速1.0mL/min,进样量10μL。结果表明,苯甲酸与山梨酸在0~320μg/mL范围内,峰面积与其浓度线性关系良好,相关系数均为0.999 76,平均回收率分别为99.0%、99.1%,重复性试验相对标准偏差分别为0.88%和0.71%(n=9)。本法准确、简便、快速,适用于食用动物油脂中苯甲酸与山梨酸含量的测定,建议用于食用动物油脂的质量控制。     

Metal accumulation in root crops grown in planters constructed from copper azole treated lumber

Preservative treated wood is often used to construct planters, but there are concerns about components migrating from the wood into the surrounding soil where they might be selectively absorbed by plants. Potential for selective accumulation was evaluated by growing radishes, carrots and potatoes in copper azole (CA) treated Douglas-fir planters. Copper levels were higher in soil adjacent to CA treated wood, but did not differ in roots or tubers grown in treated or non-treated wood. Copper levels were elevated in carrot foliage which is not normally consumed.     

Decontamination of beef carcass surface tissue by steam vacuuming alone and combined with hot water and lactic acid sprays

Hot beef carcass surface regions (outside round, brisket, and clod) contaminated with feces spread over a 5-cm2 (1-in2) area were cleaned using a steam-vacuum spot-cleaning system alone or combined with subsequent sanitizing treatments of hot water (95 degrees C at the nozzle), or warm (55 degrees C) 2% lactic acid spray, or combinations of these two sanitizing methods. These treatments were compared for effectiveness in reducing aerobic plate counts (APC) and counts of Enterobacteriaceae, total coliforms, thermotolerant coliforms, and Escherichia coli. All treatments significantly reduced the numbers of each group of bacteria on beef carcass surfaces. However, reductions obtained by steam vacuuming were significantly smaller than those obtained by a combination of steam vacuuming with any sanitizing treatment. No differences in bacterial reductions were observed between different carcass surface regions. Steam vacuuming reduced the number of different indicator organisms tested by ca. 3.0 log cycles but also spread the bacterial contamination to areas of the carcass surface adjacent to the contaminated sites. This relocated contamination after steam vacuuming was most effectively reduced by spraying with hot water and then lactic acid. This combined treatment consistently reduced the numbers of Enterobacteriaceae, total and thermotolerant coliforms, and E. coli to undetectable levels (<1.0 log10 CFU/cm2) on areas outside the initial 5-cm2 inoculated areas.     

酸活化凹土在牛羊油脱色中的应用研究

通过扫描电镜、X射线能谱、X射线衍射、傅立叶变换红外光谱和BET测试,对不同浓度的硫酸改性后的凹土进行分析.结果表明,经过合适浓度的硫酸处理的凹土可获得较好的脱色效果.对脱色前后油脂的紫外可见光谱分析表明,5%硫酸活化处理的凹土能有效地去除牛羊油中的色素.牛羊油中色素的脱除不仅与凹土比表面有关,更与合适的孔径有关.     

Determination of oxalic acid in spinach with carbon nanotubes-modified electrode

This work investigated the electrocatalytic oxidation of oxalic acid on multiwall carbon nanotubes (MWNTs) modified glassy carbon (GC) electrode. The result indicated that the oxidation of oxalic acid was greatly improved at the MWNTs-modified GC (MWNTs/GC) electrode as compared with the bare GC electrode. The effects of the MWNTs suspension amount, pH and scan rate on the electrooxidation response of oxalic acid were studied by voltammetry. The surface concentration and diffusion coefficient (D_R) of oxalic acid at the MWNTs/GC electrode were determined by chronocoulometry. This MWNTs/GC electrode presented a wide linear response ranging from 5.0 × 10⁻⁵ to 1.5 × 10⁻² M for oxalic acid. The detection limit (S/N = 3) was estimated to be 1.20 × 10⁻⁵ M. Based on this MWNTs/GC electrode, the content of oxalic acid in spinach was successfully determined.     

经壳聚糖季铵盐整理的羊毛织物酸性染料染色性能

将壳聚糖季铵盐（HTCC,DQ（季铵化度）= 93%）用于羊毛整理,探讨了整理工艺和整理后羊毛的染色性能。结果表明HTCC能很好地吸附在羊毛上,吸附量随着整理液pH值的增大而减小,随整理液中HTCC浓度的增大而增大;优化的整理条件是：HTCC浓度为10g/L,pH值3.0,温度50℃。经HTCC整理后羊毛的上染速率加快,平衡上染百分率有所提高。并且HTCC的整理能改善染色羊毛的耐洗色牢度和保持好的耐摩擦色牢度。