Chlorpyrifos residue levels on field crops (rice,maize and soybean) in China and their dietary risks to consumers

In this study, chlorpyrifos residue levels in field crops of rice, maize and soybean were investigated according to the “Guideline on Pesticide Residue Trials” of China. On the basis of the residual results, human dietary risks were further evaluated. Chlorpyrifos residues of harvest grains were firstly prepared by QuEChERS method and analyzed using Gas Chromatography Tandem Mass Spectrometry (GC–MS/MS). Dietary risks were assessed by a deterministic approach. The median residues in field trials of rice, maize and soybean were 0.617, 0.0227 and 0.0136 mg kg⁻¹, respectively. The highest residues in field trials of rice, maize and soybean were 3.23, 0.114 and 0.102 mg kg⁻¹, respectively. Chronic intake assessment indicated that only 39.0% of acceptable daily intake (ADI, 0–0.01 mg kg bw⁻¹ day⁻¹) was consumed through rice, maize and soybean. The acute hazard indexes (aHI) of adults was 26.1% of acute reference dose (ARfD, 0–0.1 mg kg bw⁻¹) and aHI of children was 63.5% of ARfD in dietary exposure assessment through rice, maize and soybean consumption. Single pathway risk assessment indicated that chlorpyrifos application on field crops in manner of the good agricultural practices didn't pose public health risks.     

β-葡聚糖生物强化大米28天经口毒性研究

目的 通过28 d经口毒性试验研究,对β-葡聚糖生物强化大米的安全性进行评价。方法 将断乳SD大鼠随机分为对照组和低、中、高剂量组(2.5、5.0和10.0 g/kg BW),每组22只,雌雄各半。按照10 mL/kg BW经口灌胃,连续给予28 d,实验前后对大鼠进行眼部检查,处死动物后进行尿常规、血液学、血生化、脏器系数测定及组织病理学检查。结果 与对照组相比,给药组动物外观、体质量、食物利用率、脏器系数、血生化和尿常规检测均没有明显差异;雄性中、高剂量组和雌性高剂量组在第4周的进食量与对照组相比具有统计学差异(P<0.05或P<0.01),但均无时间上的延续性,认为无毒理学意义;雄性中、高剂量组的血小板含量与对照组相比具有统计学差异(P<0.05),但无剂量-反应关系,仅限单个指标异常,且均在实验室参考值范围之内,认为不具有毒理学意义;高剂量组病理学检查未见与受试物有关的病理性改变。结论 在本试验条件下,SD大鼠短期经口摄入β-葡聚糖生物强化大米未见毒性作用,但长期食用的安全性尚需进一步研究。     

固相萃取和同位素内标法检测白酒中氨基甲酸乙酯

建立白酒中氨基甲酸乙酯的气相色谱-质谱快速测定方法。样品添加同位素内标后,经氨基甲酸乙酯专用萃取柱净化,随后浓缩并定容检测。用气相色谱-质谱选择氨基甲酸乙酯监测离子：62,74,89,其中定量离子为62。D5-氨基甲酸乙酯监测离子：64,76,89,其中定量离子为64。结果表明氨基甲酸乙酯定量分析在0.02～0.5 μg/mL时呈良好的线性关系,相关系数在0.999以上,检出限1.0 μg/kg,在添加了三个浓度梯度的情况下平均回收率为94.9%～95.5%,RSD≤10%。结果表明,该方法迅速可靠,适合白酒中氨基甲酸乙酯的检测。     

成都市售肉制品中硝酸盐和亚硝酸盐残留量调查

本文通过离子色谱法测定熟肉制品中硝酸盐和亚硝酸盐含量,经多次实验,该方法测定硝酸盐和亚硝酸盐含量时的相对标准偏差(RSD)分别为1.51和2.23,均小于3%,精确度高,加样回收率分别为98.97%和96.54%,准确性好。利用该方法,对成都餐饮市场所售熟肉制品中硝酸盐和亚硝酸盐的含量进行了初步检测,可为熟肉制品市场的监管提供一定的数据支持。     

1874株金黄色葡萄球菌临床分布及耐药性结果分析

目的了解四川省某医院甲氧西林敏感金黄色葡萄球菌(methicillin sensitive Staphylococcus aureus,MSSA)与耐甲氧西林金黄色葡萄球菌(methicillin resistant Staphylococcus aureus,MRSA)的临床科室分布和耐药性情况。方法回顾性分析2014年12月-2017年12月四川省某医院门诊及住院患者,包括8名因金黄色葡萄球菌引起的食物中毒患者,送检各类标本分离出SA(Staphylococcus aureus)可疑菌落1874株,对其进行鉴定和药敏检测。结果 MSSA和MRSA标本主要来源于痰液(51.31%,74.33%)、伤口分泌物(21.52%,8.96%)和脓液(10.07%,7.92%)。725株MSSA临床分离率依次为门诊(27.17%)、呼吸科(15.45%)、ICU(10.21%)、神经科(8.55%)和口腔科(5.52%),1149株MRSA依次为ICU(33.16%)、神经科(11.66%)、呼吸科(9.75%)、儿科(7.57%)和妇产科(6.27%)。耐药性结果表明,MSSA对苯唑西林、万古霉素、利奈唑胺、替考拉林敏感,对青霉素G、红霉素和阿莫西林/克拉维酸耐药率依次为89.38%、56.69%、21.51%外,对其他抗菌药耐药率均18.00%; MRSA对万古霉素利、奈唑胺、替考拉林敏感,对苯唑西林、莫西沙星、克林霉素、红霉素、青霉素G、四环素、环丙沙星、阿莫西林/克拉维酸和氨苄西林/舒巴坦的耐药率均显著高于MSSA。结论四川省某医院2014年12月-2017年12月期间临床分离的SA以MRSA为主, MSSA和MRSA在标本来源、科室分布等方面存在较大差异, MRSA耐药情况更为严重,明显高于MSSA。若要评估金黄色葡萄球菌感染风险以及病人的治疗方案,应分别考虑MRSA和MSSA的感染来源和耐药性。     

Review of the structural characterization,quality evaluation,and industrial application of Lycium barbarum polysaccharides

BackgroundLycium barbarum polysaccharides (LBPs) are considered to be the major bioactive components in L. barbarum. Due to the considerable health benefits of LBPs, and the significant research interest in LBPs, quality evaluation of LBPs and their related products is imperative for ensuring their efficacy and safety. The bioactivities of polysaccharides are closely associated with their physicochemical properties, which can be easily monitored via chemical techniques. Therefore, analysis of physicochemical properties is a more straightforward and viable approach for the quality control of polysaccharides.Scope and approachIn this review, special techniques for the structural characterization of LBPs are summarized and discussed. In addition, quality evaluation approaches of LBPs that have never been emphasized are highlighted herein. Furthermore, industrial applications of LBPs are reviewed and discussed.Key findings and conclusionsHigh-performance anion-exchange chromatography coupled with pulsed amperometric detection is one of the most effective techniques for analysis of both acidic and neutral LBPs. Size-exclusion chromatography coupled with multi-angle laser light scattering and refractive index detection is able to determine absolute molecular weights, chain conformations, and contents of LBPs. Fingerprinting analysis and saccharide mapping analysis are effective approaches for quality evaluation of LBPs. However, the lack of appropriate quality evaluation approaches indicates an unreliable regulation of LBPs and their related products. This reveals the deficiency in the quality control of commercial products. Thus, the development of reliable approaches for pharmacological activity-based quality control of LBPs and their related products must be extensively investigated.     

Modelling the disruption of essential oils glandular trichomes with compressed CO2

A theoretical model is proposed for the evaluation of the disruption efficiency of essential oils glandular trichomes (glands) with compressed CO₂. The disruption of glands occurs during the fast decompression of the bed of herbaceous material. The glands are described as closed structures slightly permeable to CO₂. When exposed to compressed CO₂, the gas slowly penetrates the glands and dissolves in the intraglandular oil until the solubility limit is reached. During the fast decompression of the bed, the dissolved gas is desorbed from the oil phase and discharged to the bulk solvent. The inability of the glands to discharge the gas, at a rate dictated by the loss of solubility in the oil with the decompression of the bed, generates a pressure gradient across the glands that may lead to its rupture. In the present model, the excess pressure is described by an equation similar to Hagen–Poiseuilles formula for viscous flow due to a pressure gradient. The maximum pressure gradient across the glands during the fast decompression of the bed is then used to calculate the percentage of glands disrupted (efficiency of disruption) assuming a normal distribution of the bursting pressures of the glands. The model was applied to experimental results where the effects of pre- and post-expansion pressure, exposure time to pre-expansion pressure and the rate of decompression were investigated. Predictions of the model are also presented.     

西藏雪莲花挥发油的GC/MS分析

The essential oils from Saussurea tridactyla were extracted by steam distillation. The chemical components of the essential oils were analyzed by GC/MS, and 23 compounds were identified, which account for 90% of the total essential oils.     

毛细管气相色谱法测定市售食用油中残留溶剂的研究

浸出法制油的过程中主要使用六号溶剂作为浸出溶剂,该方法难免造成六号溶剂在食用油中的残留,六号溶剂对食用油的品质以及人体健康都有诸多害处,而压榨油因为生产工艺不同,其中不应该含有六号溶剂的残留。顾可根据检测压榨油中是否含有六号溶剂判断压榨油中是否添加浸出油。本文建立了毛细管气相检测食用油中六号溶剂残留量的方法,并对成都和广元市场市售的压榨食用油进行了初步的检测,为两地食用油市场的监管提供初步的数据支持。