大蒜超氧化物歧化酶的分离纯化及其性质的研究

以壳聚糖为基质的金属螯合亲和层析法纯化大蒜SOD ,得到比活为 1191U/mg的酶蛋白 ,回收率为 71% ,纯化倍数为7.2 9。实验表明 ,经 8mol/L的尿素处理后大蒜SOD活性不发生变化 ,并且可耐 6 0℃高温 1h而活性不下降     

昆虫驱避剂Deet的气相色谱分析

本文采用气相色谱法，选用３％ＳＥ－３０填充柱，以正十八烷为内株，在适当的色谱条件下的Ｄｅｅｔ进行分析，出峰速度快，分离效果好，准确度和精密度均得到满意结果。     

Identification of dimethylarsinic acid as the major arsenic compound in fish sauce by liquid chromatography/electrospray ionization-mass spectrometry

ABSTRACT:   Arsenobetaine, the major arsenic compound in marine animals, is substantially non-toxic. It is, however, possible that arsenobetaine undergoes bacterial transformation during manufacturing of fermented fishery products. In the present study, therefore, three types of fish sauce were examined for arsenic concentrations and species compared with those in the raw materials (sardine, Japanese sandfish and Japanese common squid). Arsenic concentrations of the three types of fish sauce were almost equivalent to those in their raw materials, suggesting no accumulation of arsenic during fermentation. Arsenic speciation was performed by a combination of cation-exchange liquid chromatography (LC) and electrospray ionization (ESI)-single quadrupole mass spectrometry (MS). Optimal conditions of LC/ESI-MS were established to analyze seven arsenic compounds (arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine, trimethylarsine oxide, arsenocholine and tetramethylarsonium ion) found in biological samples. When analyzed by LC/ESI-MS, the major arsenic compound in the raw materials was arsenobetaine as expected, while not arsenobetaine but dimethylarsinic acid was identified as the major arsenic compound in the three types of fish sauce. These results suggest that arsenobetaine in the raw materials is converted to dimethylarsinic acid but not to arsenate with high toxicity by bacterial actions during manufacturing of fish sauce.     

Chemical Characterization of Bovine Urine with Special Reference to Oestrus

Cows' urine was analysed by gas chromatography–mass spectrometry (GC-MS). The profiles from preovulatory, ovulatory and postovulatory samples were compared to establish any qualitative and quantitative differences that might have potential value in olfactory communication. Dichloromethane was used as the solvent for extraction of the compounds. Seven different compounds were detected, of which only two were common to all the chromatograms. The chemical profile of oestrous urine was distinguished by the presence of two specific compounds, viz. di-n-propyl phthalate and 1-iodoundecane, that were not found in the other samples. As oestrous urine has been shown to elicit sexual behaviour in cattle, these two characteristic peaks may represent important chemical compounds that elicit signals that allow the bull to detect `oestrous odours'.     

Hydrocortisone Concentrations in Post-Race Urine from Horses

As hydrocortisone is an endogenous substance, it is first necessary to establish its normal concentrations so as to be able to control its use in racing animals. This study was designed to establish the hydrocortisone concentrations in post-race urine samples of horses racing in Brazil and also to evaluate the results in relation to the international threshold set for this drug. Urine samples were analysed by HPLC-UV. The results were evaluated according to the concentration range as well as sex and time of sample collection (afternoon or evening races). The results showed a high degree of variation in the concentrations of hydrocortisone in the urine (93±69 ng/ml). The maximum concentration observed was 646 ng/ml, although only a few horses (around 1%) showed levels within the range 500–650 ng/ml, 91% being in the range 0–150 ng/ml. The data suggested a normal distribution curve. Statistical analysis showed no significant influence of sex or time of sample collection.     

高效益立柱式无土栽培技术

简述了北京蔬菜研究中心研究开发的立柱式无土栽培的设施结构、适栽蔬菜种类、高效优质高产配套栽培技术、推广应用状况及注意事项。     

气相色谱法测定新鲜荔枝中“六六六”农药残留

用大品径毛细管柱气相色谱／电子捕获器（ＧＣ／ＥＣＤ）方法测定新鲜荔枝中“六六六”４种异构体的农药残留。１０ｍｉｎ即可把４种异构体有效分离检测。α－ＢＨＣ,β－ＢＨＣ,γ－ＢＨＣ,δ－ＢＨＣ平均质量比为４７．５～１２４μｇ／ｋｇ时,标准偏差为５．２２～１１．８μｇ／ｋｇ。标样的添加回收率为９２．０％～１０９％,标准曲线相关系数为０．９９４～０．９９９,方法的最低检出限为０．１４４～０．３７３μｇ／ｋ     

固定化金属螯合亲和膜制备及其性能研究

将纤维素滤纸经碱处理、环氧活化、配基偶联、固定化Ｃｕ＾２＋后制得了大孔纤维素亲和膜。检验了亲和膜的流速与负压、等温吸附、保存方法及使用次数等亲和膜性能指标。结果表明：普通纤维素滤纸可以制成性能优良的亲和膜色谱介质。     

棉田中丙硫克百威及其代谢物残留量的气相色谱分析

采用气相色谱法研究了丙硫克百威及其代谢物克百威和３－羟基克百威在棉田中的残留分析方法。结果表明：样品中的丙硫克百威和克百威用丙酮提取（３－羟在克百威经稀盐酸水解后,二氯甲烷提取,提取液在浓缩脱水后与无水乙醇反应）,再用二氯甲烷萃取,浓缩,经活性炭－弗罗里硅土柱净化,用气相色谱仪检测,当添加量在０．０５、０．５,２．０ｍｇ／ｋｇ时,各类样品的平均回收率为７６．１％￣１０６．５％,变异系数在３．３％￣