饮用水中挥发性卤代烃的顶空气相色谱分析研究

本文研究并拟订了一种饮用水中五种挥发性卤代烃的顶空气相色谱分析法，方法灵敏准确，操作简便快速，实际水样分析结果满意     

用四-(对氨基苯基)-卟啉柱前衍生的高效液相色谱法测定重金属

研究了用固相萃取富集、快速分离柱高效液相色谱法测定环境水样中镍、锡、铅、镉、汞5种重金属的方法。环境水样中的镍、锡、铅、镉、汞用四-(对氨基苯基)-卟啉(T4APP)柱前衍生,然后用ZORBAX RP18固相萃取小柱萃取富集镍、锡、铅、镉、汞的T4APP络合物,经富集后的络合物用甲醇-丙酮(体积比95∶5)为流动相,ZORBAX Stab le Bound(4.6 mm×50 mm,1.8μm)快速分离柱为固定相分离,用二极管矩阵检测器检测。镍、锡、铅、镉、汞的检测限分别为4,5,4,3,3 ng/L,分离5种重金属元素络合物的时间只需2.0 m in,相对标准偏差为2.2%~4.1%,加标回收率为88%~104%。用该法测定环境水样中的痕量镍、锡、铅、镉、汞,结果令人满意。     

Study of the levels of N‐methylcarbamate pesticides in waters of the river Huelva

A study on the levels of N‐methylcarbamate pesticides and some degradation products in waters of the river Huelva was carried out. This river constitutes the main water supply of the city of Seville at the south west of Spain with a population of almost one million inhabitants. N‐methylcarbamates were extracted from the water by using C‐18 solid phase cartridges. High performance liquid chromatography with UV detection was used to carry out the determinations. Residues of carbaryl, methiocarb sulphoxide and α‐naphthol were found in some of the analysed water samples.     

Determination of fumonisins in milk

Abstract

Fumonisin B₁ (FB₁) and fumonisin B₂ (FB₂) were determined in milk by liquid chromatography (LC) following immunoaffinity column cleanup. Recoveries from milk spiked with 5–50 ng each fumonisin/ml averaged 79–109%. The aminopentol hydrolysis product of FB₁ (AP₁) was determined by LC after cleanup on a C₁₈solid phase phase extraction column; mean recoveries were 69–83% at spiking levels of 50–100 ng AP₁/ml milk. Detection limits were of the order 3–7 ng/ml for FB₁ and FB₂, and 20–25 ng/ml for AP₁. A stability study showed no losses of FB₁ and FB₂ in milk under conditions of freezing, refrigeration and boiling. A transmission study using four cows dosed with pure FB₁, either orally (1.0 and 5.0 mg FB₁/kg b.w.) or by i.v. injection (0.05 and 0.20 mg FB₁/kg b.w.) showed no detectable residues of FB, or AP₁ in the milk, with or without hydroiytic treatment with β‐glucuronidase/sulfatase to liberate any conjugates.     

Studies on the distribution op β‐ and γ‐isombrs op hexachlorocyclohexane in rat tissues

Abstract

A study of the comparitlve distribution pattern of β‐ and γ‐isomers of hexachlorocyclohexane (HCH) in albino rat tissues as a function of duration of treatment at two dose levels revealed different accumulation patterns for the two isomers in tissues. In general, the accumulation pattern was found to be in the order: fat > kidney > lungs > liver > muscle > heart > spleen > brain > blood for β‐HCH and fat > brain > kidney > muscle > lungs > heart > spleen > liver > blood for γ‐HCH. The tissue accumulation of β‐isomer was always greater than that of γ‐isomer in any tissue except in brain. Brain β‐HCH residue levels were relatively lower than in many other tissues except blood, whereas brain γ‐HCH concentration was only next to fat. A higher dose or a longer period of treatment generally produced a more marked elevation of tissue residue levels in β‐HCH fed rats, but not in γ‐HCH treated animals.

Food restriction subsequent to a period of exposure to dietary β‐ or γ‐HCH caused a mobilization of depot fat without drastic redistribution of the HCH residues stored in it. During food restriction, the residue levels in fat and muscle increased much. The residue levels in brain and other organs were not adversely affected during partial starvation.     

Influence of humic fractions on retention of isoproturon residues in two Moroccan soils

The influence of different fractions of soil organic matter on the retention of the herbicide isoproturon (IPU) has been evaluated. Water and methanol extractable residues of ¹⁴C labeled isoproturon have been determined in two Moroccan soils by β -counting–liquid chromatography. The quantification of bound residues in soil and in different fractions of soil humic substances has been performed using pyrolysis/scintillation-detected gas-chromatography. Microbial mineralization of the herbicide and soil organic matter has been also monitored. Retention of isoproturon residues after 30-days incubation ranged from 22% to 32% (non-extractable fraction). The radioactivity extracted in an aqueous environment was from 20% to 33% of the amount used for the treatment; meanwhile, methanol was able to extract another 48%. Both soils showed quantities of bound residues into the humin fraction higher than humic and fulvic acids. The total amount of residues retained into the organic matter of the soils was about 65 % of non-extractable fraction, and this percentage did not change with incubation time; on the contrary, the sorption rate of the retention reaction is mostly influenced by the clay fraction and organic content of the soil. Only a little part of the herbicide was mineralized during the experimental time.     

Determination of Alphacypermethrin in the Air by Capillary Gas Chromatography

A new method for sampling and chemical analysis of alphacypermethrin in workplace air has been described. Air samples were taken using a glass tube filled with silica gel with chemically bounded octadecyl phase. Chromatographic determinations were conducted using an HP-5 capillary column (10 m x 0.53 mm) and an electron-capture detector. Alphacypermethrin recovery was 100.15%. The calculated detection limit for a 60-L air sample was 0.0001 mg/m3.     

便携式气相色谱-氢火焰离子化检测器法测定低浓度总烃的氧气干扰特征研究

研究了采用便携式气相色谱-氢火焰离子化检测器法测定气体中的总烃浓度时,氧气浓度对测定结果的影响,并采用多元线性回归模型对总烃的测定结果进行了校准。当总烃的实际浓度不低于9 mg/m³时,氧气的干扰较小(相对标准偏差≤2%)。在试验的所有总烃实际浓度下(1~200 mg/m³),当氧气浓度为1%~7%时,也无需考虑氧气干扰的影响(相对标准偏差≤2%)。当总烃的实际浓度低于9 mg/m³且氧气浓度为9%~21%时,需依据多元线性回归分析原理并采用模型对测得的总烃浓度进行校准。线性回归方程分析结果显示,模型拟合情况良好(R²=0.999),可以用来修正测试结果,从而得到更加准确的总烃实际浓度。     

上海城区PM2.5中有机组分及硝基芳香化合物分布特征

硝基芳香化合物（NACs）是细颗粒物中含氮化合物的重要组成部分,研究其在大气中的污染特征和季节变化,有助于表征大气细颗粒物中含氮有机化合物特性,并为城市氮氧化物削减提供科学支撑.采集并分析了上海城区2018年3月～2019年2月大气PM_2.5样品,采用超高效液相色谱-轨道阱质谱（UPLC-Orbitrap MS）在PM_2.5样品中定性检测到了2 439～3 695个有机物,内标法定量了9种NACs,春季ρ（NACs）范围为3.12～16.8 ng·m^-3,平均值为9.31 ng·m^-3;夏季ρ（NACs）范围为1.05～9.70 ng·m^-3,平均值4.16 ng·m^-3;秋季ρ（NACs）范围为2.87～36.27 ng·m^-3,平均值9.84 ng·m^-3,冬季ρ（NACs）范围为4.83～56.23 ng·m^-3,平均值为22.37 ng·m^-3. 9种硝基芳香化...     

低能离子诱变产表面活性剂的烃降解菌研究

为有效治理石油污染土壤,从长期遭受石油污染的土壤中筛选出一株烃降解菌8-11作为出发菌,利用低能N+注入烃降解菌进行诱变,在能量为20 keV、剂量为90×2.6×1013ions/cm2条件下筛选出一株高效烃降解菌——诱变菌23。原油摇瓶发酵实验表明诱变菌对原油的降解率达到74%;降解后原油的全烃气相色谱图显示,经过7 d的作用,原油中的正构烷烃完全降解。诱变菌23能够产生大量的生物表面活性物质,傅里叶红外光谱分析表明其产生的生物活性物质为糖脂类化合物,该糖脂类生物表面活性剂能使发酵液的表面张力从空白对照的56.1 mN/m降低为29.3 mN/m。研究表明诱变菌23具有较高的烃降解能力,能有效降低表面张力,具有较大的应用潜力。