高效液相色谱-串联质谱法测定蜂蜜中氯霉素、甲砜霉素、氟甲砜霉素及甲硝唑

目的 建立蜂蜜中氯霉素、甲砜霉素、氟甲砜霉素及甲硝唑残留的高效液相色谱-串联质谱同时测定方法。方法 以乙酸乙酯作为提取剂,经涡旋混匀提取后,氮吹至干,用5%甲醇水溶解,Oasis HLB固相萃取柱净化。经甲醇洗脱,洗脱液经45℃水浴氮吹至干,流动相涡旋溶解,上机测定。高效液相色谱分离、串联质谱检测,采用多离子反应监测（MRM）模式,内标法定量。结果 在优化条件下,4种抗生素浓度在0.1～5.0μg/L范围内,线性关系良好,相关系数（r）≥0.9953,方法检出限≤0.015μg/kg,不同基质中平均加标回收率为78.5%～95.1%,相对标准偏差（RSD）为2.8%～10.7%。结论 该方法快速、灵敏、准确,适用于蜂蜜中氯霉素、甲砜霉素、氟甲砜霉素及甲硝唑的同时测定。     

Influence of chloride on silver uptake by two green algae, Pseudokirchneriella subcapitata and Chlorella pyrenoidosa

Silver bioavailability in the presence of chloride was estimated from short-term (< or = 60 min) uptake experiments with two green algae, Pseudokirchneriella subcapitata and Chlorella pyrenoidosa. In the first experiment, silver uptake was monitored under two concentration regimes in which total dissolved silver ([Ag]tot) and [Cl] were manipulated to maintain [Ag+] at a constant value (10 nM). Comparable uptake rates were measured for both treatments despite the dramatic changes in [Cl] and [Ag]tot. In the second experiment, ambient [Ag]tot was held constant (10 or 115 nM), but [Cl] was varied (0.005-50 mM) to explore the whole range of silver chloro-complexes. Intracellular silver varied markedly along the [Cl] gradient and exhibited a clear, positive correlation with ambient [Ag+] for both algae. We conclude that the biotic ligand model reliably describes silver bioavailability in the presence of chloride for the two test algae and that its applicability depends on the relative magnitudes of silver fluxes through the unstirred diffusion layer and across the cell membrane, with the latter being affected by the presence or absence of a Cu(I) transporter. In the presence of chloride, no evidence was found for the internalization of silver via anion transport or passive diffusion of the neutral mono-chloro-complex, AgCl0.     

Differential sensitivity of two green algae,Scenedesmus obliqnus and Chlorella pyrenoidosa,to 12 pesticides

Growth-inhibiting tests were carried out for 12 pesticides (including 11 fungicides: fosetyl-aluminum, benomyl, metalaxyl, iprodione, dimetachlone, carbendazim, thiophanate-methyl, bismerthiazol, procymidone, zineb, chlorothalonil, and the acaricide abamectin) in the green algae Chlorella pyrenoidosa and Scenedesmus obliqnus and the differential sensitivities of the two green algae to those pesticides were compared. The results indicate that the acute toxicity of benomyl to C. pyrenoidosa and S. obliqnus is the highest among all of the pesticides tested and is close to that of the photosynthesis-inhibiting herbicides atrazine, simazine, and chlorotoluron. Meanwhile, algal species vary widely in their response to the pesticides. The results demonstrated that there was a differential response to various pesticides by the two species of algae and that the sensitivity of various species of algae exposed to chlorothalonil varied by nearly two orders of magnitude; sensitivity to thiophanate-methyl varied by more than one order. Investigations using different algal species as test organisms have demonstrated that algae vary greatly in their response to chemicals. Differential sensitivity of green species to the compounds could induce species shifts within communities.     

Effects of Salinity and Temperature on the Bioavailability of Dispersed Petroleum Hydrocarbons to the Golden-Brown Algae, Isochrysis galbana

Comparative studies were done to determine the influence of a dispersant on the bioavailability of naphthalene from crude oil to the unicellular golden-brown algae, Isochrysis galbana, under changing temperature and salinity conditions. Conditions were selected to represent a range (two temperatures, 12 and 20°C, and two salinities, 22 and 34‰) encountered in Pacific waters, where extensive crude oil transport and refining occurs. Cells were exposed to laboratory preparations of either the water-accommodated fraction (WAF) of Prudhoe Bay crude oil (PBCO) or a dispersed oil (DO) mixture of PBCO and Corexit 9527? spiked with [U-¹⁴C]naphthalene. Uptake increased by as much as 50% in DO, 20°C exposures run at 22‰ (0.24 μmol naphthalene/g algae in WAF, 0.37 μmol naphthalene/g algae in DO) compared with comparable exposures at 34‰ (0.23 μmol naphthalene/g algae in WAF, 0.37 μmol naphthalene/g algae in DO). A 24-h bioaccumulation factor (BAF) calculated in the absence of steady state indicated increasing bioaccumulation with decreasing temperature. No significant variation in relative metabolite composition occurred under the different experimental conditions. Results of these experiments showed that the use of dispersants enhanced the uptake of naphthalene by microalgae under a variety of temperature and salinity conditions, independent of aqueous concentration. Received: 18 September 1997/Accepted: 5 February 1998     

赤霉素对球等鞭金藻3011生物量、细胞形态与不同生长时期群体细胞活性的影响

目的 观察赤霉素(gibberellins,GA)的添加量对球等鞭金藻3011(Isochrysis galbana 3011)生物量、细胞形态与不同生长时期群体细胞活性的影响.方法 取处于指数生长期的球等鞭金藻3011藻液,分别添加终浓度为0(溶剂对照)、0.001、0.003、0.005、0.007、0.01、0....     

蛋白核小球藻对小鼠细胞免疫系统的影响

目的:探讨蛋白核小球藻对健康小鼠细胞免疫系统的影响.方法:选用BalB/c正常小鼠,随机分组,经口给予小鼠不同剂量的小球藻粉水溶液0,0.15,1.50,4.50 g/kg·bw,每日1次,30 d后测量小鼠迟发型变态反应,co.LA诱导的小鼠淋巴细胞转化能力.结果:迟发型变态反应试验中4.50剂量组与对照组比较差异有显著性(P＜0.01);ConA诱导的小鼠淋巴细胞转化能力试验中0.15剂量组与对照组比较差异有显著性(P＜0.05).结论:蛋白核小球藻能增强健康小鼠细胞免疫系统的功能.     

Effects of organic solvents and solvent-atrazine interactions on two algae, Chlorella vulgaris and Selenastrum capricornutum

When assessing pesticides toxicity on test organisms, the use of organic solvents is frequently required to formulate solutions of pesticides having low or moderate water solubility. These solvents may influence the results of toxicity tests. This study examined the effects of ethanol and dimethyl sulfoxide (DMSO) on two species of algae, Chlorella vulgaris and Selenastrum capricornutum. The interactives effects of these organic solvents with various concentrations of atrazine were tested to analyse how these solvents can affect the toxicity of atrazine. Toxicity was measured as the change in chlorophyll (a) content (estimated via fluorescence) in cultures of the test organism that were incubated over a 96-h period at standard conditions of temperature and light. In the absence of atrazine, ethanol was toxic to both algae, yielding significant inhibition of chlorophyll (a) content at concentrations as low as 0.05%. Morever, S. capricornutum was less sensitive to ethanol than was C. vulgaris. DMSO did not show any toxic effects on either chlorophycea. At concentrations up to 0.5%, DMSO interacted additively with atrazine for both chlorophycea. An additive response was also observed with ethanol towards S. capricornutum. For C. vulgaris, ethanol interacted antagonistically at most of atrazine concentrations and gave few additive and synergistic interactions. An additive response of an atrazine-solvent mixture indicate the inherent toxicity of the atrazine. Since DMSO generally gave additive responses for both algae, it can be considered as an adequate organic solvent to use in bioassays.     

Chloride adduct tandem mass spectrometry for the quantification of thiamphenicol and florfenicol in bovine muscle

LC–MS/MS analytical performance characteristics of chloride adduct ions [M + Cl]⁻ of thiamphenicol (TAP) and florfenicol (FFC) as precursor ions for quantification were studied. The calculations were based on a THF/Water solvent system to which dichloromethane was added as an additive at a composition of 2 % to generate chloride (Cl⁻) ions during electrospray ionization (ESI) of the solutions. The selectivity and signal to noise (S/N) ratio when the [M + Cl]⁻ adduct ions were used as precursor ions were excellent compared to deprotonated [M−H]⁻ ions that are traditionally used to determine the two analytes. The S/N ratios in the total ion chromatogram (TIC) of TAP and FFC were 577 and 3062 respectively, compared to 167 and 452 when [M−H]⁻ were used at the same spike levels of 50 and 100 μg/kg respectively. The limits of detection (LODs) for TAP and FFC were 4.0 and 3.7 μg/kg respectively using [M + Cl]⁻ as opposed to 2.1 and 4.3 μg/kg respectively when [M−H]⁻ were used. [M + Cl]⁻ adduct ions proved to be excellent substitutes for [M−H]⁻ especially where identity and selectivity would be the key drivers of the analytical method before quantification of the two analytes.     

酚酸类物质对铜绿微囊藻以及蛋白核小球藻的抑藻作用

目的研究单一以及复合酚酸对混合藻类的抑制作用。方法选用水杨酸、肉桂酸与焦性没食子酸单一或两两结合作用于铜绿微囊藻(Microcystis aeruginosa)与蛋白核小球藻(Chlorella pyrenoidosa)的复合体系,以叶绿素为生物量指标,计算其单一酚酸抑藻的半最大效应浓度(EC_(50)),判断其联合抑藻的复合效应。结果三种酚酸单独对铜绿微囊藻和蛋白核小球藻混合藻类均有一定抑制作用,抑制作用为焦性没食子酸水杨酸肉桂酸,实验第6 d,这三种酚酸单独对铜绿微囊藻和蛋白核小球藻混合体系抑制作用的EC_(50)依次为:7.87、64.90以及89.34 mg/L;复合酚酸对混合藻的抑制作用为焦性没食子酸与水杨酸组合焦性没食子酸与肉桂酸组合水杨酸与肉桂酸组合,前两种组合表现为协同抑藻作用,后一种组合的抑藻效应为相加作用。结论某些酚酸联合应用可协同抑藻,从而能减少其单一酚酸的使用量,具有相对较高的环境安全性。     

Influence of Dispersants on the Bioavailability of Naphthalene from the Water-Accommodated Fraction Crude Oil to the Golden-Brown Algae, Isochrysis galbana

The golden-brown algae Isochrysis galbana, a primary producer, was used to determine the influence of the chemical dispersing agent, Corexit 9527^?, on the bioavailability of naphthalene. Cells were exposed to laboratory preparations of either the water-accommodated fraction (WAF) of Prudhoe Bay crude oil (PBCO) or a dispersed oil (DO) mixture of PBCO and Corexit 9527 spiked with [U-¹⁴C]naphthalene. Uptake was determined by the amount of algae-associated [¹⁴C]. High-pressure liquid chromatography (HPLC) co-chromatography was used to fractionate and identify metabolic products. A 24-h bioaccumulation factor (BAF) was calculated in the absence of steady state. The presence of Corexit 9527, had significant influence (p = 0.001) on the uptake of naphthalene, but no significant effect on the 24-h BAF (BAF: 168 and 180 from WAF and DO, respectively), or metabolic fate of naphthalene in I. galbana. Results of this research indicate that dispersants have the potential to increase organismal exposure to certain petroleum hydrocarbons without increasing their aqueous concentration. Received: 19 September 1997/Accepted: 5 February 1998     

Acute toxicity of oxytetracycline and florfenicol to the microalgae Tetraselmis chuii and to the crustacean Artemia parthenogenetica

Aquaculture systems are a potentially significant source of antibacterial agents to the aquatic environment. The antibacterials oxytetracycline (OTC) and florfenicol (FLO) have been widely used in aquaculture. These pharmaceuticals may cause deleterious effects on wild aquatic organisms accidentally exposed to them. Therefore, the objective of this study was to evaluate the acute toxicity of OTC and FLO to the microalgae Tetraselmis chuii and to the crustacean Artemia parthenogenetica, using culture growth inhibition and death, respectively, as effect criteria. OTC and FLO were found to inhibit the growth of T. chuii cultures, with 96 h IC(50) values of 11.18 and 6.06 mg/L, respectively. OTC 24 and 48 h LC(50) values for A. parthenogenetica were 871 and 806 mg/L, respectively. FLO did not cause mortality of A. parthenogenetica. These results indicate that OTC and FLO are considerably more toxic to T. chui than to A. parthenogenetica. They also indicate that the concentrations required to induce mortality to A. parthenogenetica only in exceptional conditions will occur in the environment.     

Effect of hexachlorobenzene on some growth parameters ofChlorella pyrenoidosa

Summary Chlorella pyrenoidosa was incubated with HCB (0.001–10.0 ppm) in a light-thermostat at 30°C for 46 h with continuous light (4000 Lux) and aeration. HCB decreased growth as deduced from measurements of chlorophyll content, dry matter, carbohydrate content, and total nitrogen. Incubation with HCB for three months in Erlenmeyerflasks resulted in an increase of chlorophyll over control values in cultures receiwing 0.1 and 1.0 ppm HCB. After transfer of the cultures from Erlenmeyer-flasks to growth conditions of a light-thermostat, growth of the algae was greatly enhanced by all HCB concentrations studied; a concentration of 0.1 ppm being most effective.     

Differential sensitivity of two green algae, Scenedesmus quadricauda and Chlorella vulgaris, to 14 pesticide adjuvants

Growth-inhibition tests for 14 pesticide adjuvants which are widely used to manufacture various pesticidal formulations in China, were performed on the green algae Scenedesmus quadricauda, and Chlorella vulgaris to compare differential sensitivity among populations of these algae to the adjuvants. The results showed that the acute toxicities of 700#, 1601#, By-140, and SOPA to S. quadricauda and C. vulgaris were the lowest among all the tested adjuvants. The acute toxicities of Tween 80, O-25, and AEO-13 phosphate to the selected two green algae were intermediate among the tested adjuvants. The acute toxicities of 602#, 500#, OT, NP-10, OP-10, and JFC were the highest. Meanwhile, the algal species vary widely in their response to those adjuvants. The results showed that there was a differential response to various adjuvants among the selected algal species and that the sensitivities of the various algal species exposed to 1601# and OT varied by nearly 1 order and to 700#, and By-140 varied by over 1 order of magnitude. In addition, the NOEC and LOEC values of the selected 14 adjuvants to S. quadricauda and C. vulgaris were tested; the result showed that NOEC < or = EC10相似文献