High performance liquid chromatographic determination of clocapramine in feed and plasma

A high performance liquid chromatographic method is described for the determination of clocapramine in animal feed and plasma. Samples are made alkaline and then extracted with chloroform containing opipramol as internal standard. For plasma samples, the organic phase is evaporated to dryness under a stream of nitrogen, and the residue is dissolved in dichloromethane-methanol. Extracts are chromatographed on silica gel with dichloromethane-methanol-ammonia (100 + 10 + 0.25) as eluant, and quantitated using an internal standard. Within-day precision for plasma extracts (n = 15) was 3.39, 5.7, and 4.13% at 5, 10, and 15 mg clocapramine/L plasma, respectively, and day-to-day precision was 4.6, 6.8, and 4.4% at the same levels. The detection limit was 0,5 mg/L. Recovery from feed over the concentration range 2-6 g/kg was greater than 96%.     

Potentiometric flow injection determination of glycerol in distilled spirits.

A single-line flow injection system including a tubular periodate-selective electrode without inner reference solution is proposed for glycerol determination in distilled spirits, based on oxidation of this polyol by periodate. Interferences due to 5.0 mg L(-1) Cu, 5000 mg L(-1) sucrose, and 3000 mg L(-1) fructose plus glucose were investigated. The procedure is characterized by a linear response for 20-500 mg L(-1) glycerol (r > 0.9999, n = 7), a relative standard deviation of results of <0.03, and an analytical throughput of 30 determinations per hour. Accuracy was assessed by applying the procedure to distilled spirits of sugarcane and grape already analyzed by HPLC; in addition, recoveries within 96 and 120% were obtained.     

Kinetic enzymatic determination of glycerol in wine and beer using a sequential injection system with spectrophotometric detection

A sequential injection system for the automatic determination of glycerol in wine and beer was developed. The method is based on the rate of formation of NADH from the reaction of glycerol and NAD+ catalyzed by the enzyme glycerol dehydrogenase in solution. The determination of glycerol was performed between 0.3 and 3.0 mmol L(-1) (0.028 and 0.276 g L(-1)), and good repeatability was attained (rsd < 3.6%, n = 5) for all samples tested. The determination rate was 54 h(-1), the reagent consumption was only 0.75 micromol of NAD+ and 5.4 ng of enzyme per assay, and the waste production was 2.12 mL per assay. Results obtained for samples were in agreement with those obtained with the batch enzymatic method.     

Direct and selective flow-injection method for the simultaneous spectrophotometric determination of calcium and magnesium in red and white wines using online dilution based on "Zone Sampling".

The present work reports a selective and simple flow injection method for the direct and simultaneous determination of calcium and magnesium ions in red, rose, and white wines. Both ions react with methylthymol blue (MTB) at a strongly basic medium to form colored complexes that are monitored spectrophotometrically (lambda(max) = 610 nm). The simultaneous determination is achieved by online masking of magnesium by 8-hydroxyquinoline (8-HQ). Incorporating an online dilution mode based on the "zone sampling" technique in the FI system, the determination of both analytes was achieved without any pretreatment of the samples, in the range 0-350 mg L(-1) and 0-200 mg L(-1) for Ca(II) and Mg(II), respectively. The 3 sigma detection limits were quite satisfactory (2.1 and 1.8 mg L(-1) for Ca(II) and Mg(II) respectively), and the precision was 1.2% (at a mixture of 100.0 mg L(-1) Ca(II) + 100.0 mg L(-1) Mg(II), n = 12). A detailed study of interferences proved that the proposed method is highly selective. The application of the method to the direct analysis of red, rose, and white wines yielded excellent results compared with those obtained by using FAAS as a reference method (e(r) < 2.8%).     

Phosphite determination in fertilizers after online sequential sample preparation in a flow injection system

A flow injection spectrophotometric system is proposed for phosphite determination in fertilizers by the molybdenum blue method after the processing of each sample two times on-line without and with an oxidizing step. The flow system was designed to add sulfuric acid or permanganate solutions alternately into the system by simply displacing the injector-commutator from one resting position to another, allowing the determination of phosphate and total phosphate, respectively. The concentration of phosphite is obtained then by difference between the two measurents. The influence of flow rates, sample volume, and dimension of flow line connecting the injector-commutator to the main analytical channel was evaluated. The proposed method was applied to phosphite determination in commercial liquid fertilizers. Results obtained with the proposed FIA system were not statistically different from those obtained by titrimetry at the 95% confidence level. In addition, recoveries within 94 and 100% of spiked fertilizers were found. The relative standard deviation (n = 12) related to the phosphite-converted-phosphate peak alone was 相似文献   

不同施肥对双季稻田径流氮磷流失特征的影响

通过定位试验,研究了不施氮肥(WN)、单施化肥(HF)、猪粪替代20%氮肥(ZF)、沼渣沼液替代20%氮肥(ZYF)、堆肥替代20%氮肥(DF)、早稻绿肥、晚稻稻草代替20%氮肥(LDF)6种不同施肥处理下双季稻径流氮磷含量和累积流失负荷的影响。结果表明,水稻基肥和追肥后,径流水中全氮、硝态氮、铵态氮、全磷和水溶性磷含量逐渐下降。HF处理双季稻季径流水中全氮、铵态氮、硝态氮平均含量最高,分别为5.91,3.65,0.82mg/L。相比HF处理,有机物料替代20%氮肥处理能够降低径流水中全氮、铵态氮、硝态氮的平均含量,其中以DF处理下降幅度最大,分别下降1.18,0.71,0.14mg/L;除DF处理外,有机物料替代20%氮肥能够增加径流水中全磷和水溶性磷的平均含量。相比HF处理,有机物料替代20%氮肥能够减少氮素径流流失负荷,以DF处理总氮、铵态氮和硝态氮累积流失负荷最小,分别为10.25,6.17,1.71kg/hm2;DF处理磷素流失负荷与单施化肥处理持平。综上,DF处理能够降低径流水中氮磷流失负荷,对于保护环境和控制面源污染具有重要意义。     

Enriched accumulation and biotransformation of selenium in the edible seaweed Laminaria japonica

Accumulations of selenium in kelp Laminaria japonica cultured in seawater was achieved by adding selenite (Na2SeO3) with or without N-P (NaNO3 + NaH2PO4) nutrients at different concentrations. Biotransformation of selenium in the kelp was investigated through measuring the selenium of biological samples and different biochemical fractionations. The results showed that the optimal selenite-enrichment concentration is 200 mg L(-1), which can allow the kelp to accumulate a total selenium content from 0.51 +/- 0.15 to 26.23 +/- 3.12 microg g(-1) of fresh weight (fw). Selenium composition analysis of kelp (control group) showed that selenium is present as organic selenium, which is up to 86.22% of the total selenium, whereas inorganic selenium is barely 4.85%. When L. japonica was exposed for 56 h in seawater containing 200 mg L(-1) Na2SeO3, the organic selenium was 16.70 microg g(-1) of fw (68.23%) and inorganic selenium was 4.71 microg g(-1) of fw (19.26%). The capability of accumulation of selenium was further enhanced by adding N-P nutrients to the selenite-enriched medium. Total selenium is increased to be 33.65 microg g(-1) of fw at optimal concentration of N-P nutrient (150 mg L(-1) NaNO3 and 25 mg L(-1) NaH2PO4), whereas the inorganic selenium was not increased and remained at 4.597 microg g(-1) of fw (13.36%), and the increased part of selenium was organic selenium. This implied that kelp L. japonica could effectively transform inorganic selenium into organic selenium through metabolism.     

A commercial extract of fruits and vegetables, Oxxynea, acts as a powerful antiatherosclerotic supplement in an animal model by reducing cholesterolemia, oxidative stress, and NADPH oxidase expression

The effects of fruit and vegetable extract (Oxxynea) on plasma cholesterol, early atherosclerosis, cardiac production of superoxide anion, and NAD(P)H oxidase expression were studied in an animal model of atherosclerosis. Thirty six hamsters were divided into two groups of 18 and fed an atherogenic diet for 12 weeks. They received by gavage either water or Oxxynea in water at a human dose equivalent of 10 fruits and vegetables per day. Oxxynea lowered plasma cholesterol and non-HDL cholesterol, but not HDL-cholesterol, and increased plasma antioxidant capacity. It also strongly reduced the area of aortic fatty streak deposition by 77%, cardiac production of superoxide anion by 45%, and p22phox subunit of NAD(P)H oxidase expression by 59%. These findings support the view that chronic consumption of antioxidants supplied by fruits and vegetables has potential beneficial effects with respect to the development of atherosclerosis. The underlying mechanism is related mainly to inhibiting pro-oxidant factors and improving the serum lipid profile.     

Determination of residual cephalexin in chick tissues by Bacillus stearothermophilus paper disc assay

A paper disc method is described for determination of residual cephalexin (CEX) in chick tissues. A trichloroacetic acid extract of plasma and tissues is chromatographed on a macroreticular resin (Diaion HP-20) column to remove endogenous antibacterial substances interfering with the assay. The eluate is evaporated to dryness and the residue, dissolved in methanol-water (1 + 2), is subjected to a paper disc assay using Bacillus stearothermophilus var. calido-lactis C953 NIZO as a test organism. The detection limit was 0.0375 ppm in tissue; the average recovery of CEX ranged from 72.4% in skin to 90.4% in plasma. Water containing 200 or 500 mg/L of CEX was given ad libitum to 2-week-old chicks for 10 days; the highest levels of CEX were found in the kidney, and the lowest were found in muscle at 0 h of withdrawal. CEX disappeared from most tissues at 24 h after withdrawal except from skin of chicks given 500 mg/L. However, the drug was not detected in the skin at 48 h after withdrawal.     

荔枝皮原花青素对模拟食品体系中糖基化终产物的抑制效果

为控制美拉德反应过程中生成的晚期糖基化终末产物(advanced glycation end products,AGEs),该文研究了荔枝皮原花青素(litchi pericarp procyanidins,LPPC)对模拟食品体系中AGEs的抑制作用。采用α-乳糖/L-赖氨酸模拟食品体系,考察了不同反应时间、温度时LPPC对AGEs的抑制效果,并探讨了多种金属离子对抑制作用的干预。结果表明:在80℃加热2.5 h时,1 mg/m L LPPC对模拟食品体系中AGEs的抑制率达到最大,为79.92%±5.21%;而100℃加热30 min时,LPPC的最大抑制率为63.37%±4.12%。当向模拟体系中加入金属离子(Al~(3+)、Ca~(2+)、Cu~(2+)、Fe~(2+)、Mg~(2+)、Zn~(2+))时,低浓度金属离子表现出抑制AGEs生成的作用,高浓度下反而促进其生成。与仅添加LPPC相比,金属离子在低浓度时减弱了LPPC对AGEs的抑制能力,在高浓度时则无显著影响(P0.05)。研究结果为天然AGEs抑制剂LPPC的研发提供了理论参考。     

Simple and inexpensive flow L-glutamate determination using pumpkin tissue

This work refers to a very easy to implementate flow injection system with potentiometric detection for l-glutamate determination in food samples. The proposed procedure is based on measurement of carbon dioxide produced by decarboxylation of l-glutamate catalyzed by l-glutamate decarboxylase (E.C. 4.1.1.1.5) from Cucurbita maxima (pumpkin). The FI potentiometric system includes an enzymatic reactor with a length of 8 cm and thickness of 5 mm packed with 200 mg of a C. maxima outer layer cut in to small pieces. The proposed procedure allowed l-glutamate determinations in the concentration interval of 10-100 mmol L(-1) for an injected sample volume of 50 microL. A phosphate buffer (0.1 mol L(-1), pH 5.5) solution flowing at 1.4 mL min(-1) was used as the carrier solution in the system. The results obtained in the analysis of food samples revealed a relative error lower than 5% when compared with those provided by the spectrophometric reference procedure. The immobilized reactor retained its initial activity for 21 days. It was possible to measure 40 samples/h with the flow system proposed.     

Phycobiliprotein C-phycocyanin from Spirulina platensis is powerfully responsible for reducing oxidative stress and NADPH oxidase expression induced by an atherogenic diet in hamsters

The effects of spirulina and its chromophore phycocyanin, both without bound Se or selenium-enriched, were studied on plasma cholesterol, early atherosclerosis, cardiac production of superoxide anions, and NAD(P)H oxidase expression in hamsters. Forty hamsters were divided into 5 groups of 8 and fed an atherogenic diet for 12 weeks. They received by gavage either 7.14 mL/(kg day) phycocyanin (PC), Se-rich phycocyanin (SePC), spirulina (SP) or Se-rich spirulina (SeSP) in water, or water as control. SeSP and SePC supplied 0.4 microg of Se per 100 g body weight. Plasma cholesterol and non-HDL cholesterol concentrations were lower in group consuming SePC. HDL-cholesterol was never affected. SePC significantly increased plasma antioxidant capacity by 42% compared with controls. A sparing effect in liver glutathione peroxidase (87% on average) and superoxide dismutase (56% on average) activity was observed for all the groups compared to controls. Aortic fatty streak area was significantly reduced in the experimental groups, especially by PC (82%) and SePC (85%). Cardiac production of superoxide anion significantly decreased by approximately 46-76% in the four experimental groups and especially in SePC group (76%). The expression of p22phox subunit of NAD(P)H oxidase decreased by 34% after consumption of SePC. The results indicate that chronic consumption of Se-rich spirulina phycocyanin powerfully prevents the development of atherosclerosis. The underlying mechanism is related mainly to inhibiting pro-oxidant factors and at a lesser extent improving the serum lipid profile.     

Orally administered delphinidin 3-rutinoside and cyanidin 3-rutinoside are directly absorbed in rats and humans and appear in the blood as the intact forms

Four components of black currant anthocyanins (BCA), delphinidin 3-O-beta-rutinoside (D3R), cyanidin 3-O-beta-rutinoside (C3R), delphinidin 3-O-beta-glucoside (D3G), and cyanidin 3-O-beta-glucoside (C3G), were found to be directly absorbed and distributed to the blood and excreted into urine as the glycosylated forms. In a rat study, following oral administration of purified D3R, C3R, and C3G (800 micromol/kg of body weight), the anthocyanins were detected in the plasma and the C(max) values were 580 +/- 410, 850 +/- 120, and 840 +/- 190 nmol/L, respectively, 0.5-2.0 h after administration. In a human study, when a mixture of BCA [6.24 micromol (3.58 mg) consisting of 2.75 micromol (1.68 mg) of D3R, 2.08 micromol (1.24 mg) of C3R, 1.04 micromol (0.488 mg) of D3G, and 0.37 micromol (0.165 mg) of C3G/kg of body weight)] was orally ingested by eight volunteers, D3R, C3R, D3G, and C3G were detected in the plasma and urine. The plasma C(max) values were 73.4 +/- 35.0, 46.3 +/- 22.5, 22.7 +/- 12.4, and 5.0 +/- 3.7 nmol/L, respectively, 1.25-1.75 h after intake, and the cumulative excretion of the four compounds in urine in the period 0-8 h after intake was 0.11 +/- 0.05% of the dose ingested. These results indicate that 3-O-beta-rutinosyl anthocyanins were directly absorbed and distributed to the blood.     

Atomic absorption spectrophotometric determination of chromium in foods

A method is reported for determination of chromium in foodstuffs. Organic matter is digested with nitric acid, followed by oxidation to Cr(VI) and extraction with methyl isobutyl ketone (MIBK) after HCl addition. Chromium determinations are performed by flame absorption spectroscopy. Absence of interferences is verified and recovery tests are performed on food samples. Quantitation limit (3.8 ng/mL), accuracy (NBS Standard Reference Material 1,573 Tomato Leaves, 4,500 +/- 500 ng/g, found 3,860 +/- 409 ng/g), and precision (CV for vegetable matrix = 9.05%, CV for animal matrix = 14.95%) of the procedure are evaluated.     

Determination of total sulfur in agricultural samples by high-resolution continuum source flame molecular absorption spectrometry

The usefulness of molecular absorption was investigated for the determination of total sulfur (S) in agricultural samples by high-resolution continuum source flame molecular absorption spectrometry. The lines for CS at 257.595, 257.958, and 258.056 nm and for SH at 323.658, 324.064, and 327.990 nm were evaluated. Figures of merit, such as linear dynamic range, sensitivity, linear correlation, characteristic concentration, limit of detection, and precision, were established. For selected CS lines, wavelength-integrated absorbance equivalent to 3 pixels, analytical curves in the 100-2500 mg L(-1) (257.595 nm), 250-2000 mg L(-1) (257.958 nm), and 250-5000 mg L(-1) (258.056 nm) ranges with a linear correlation coefficient better than 0.9980 were obtained. Results were in agreement at a 95% confidence level (paired t test) with those obtained by gravimetry. Recoveries of S in fungicide and fertilizer samples were within the 84-109% range, and the relative standard deviation (n=12) was typically <5%.     

Lutein and zeaxanthin in leafy greens and their bioavailability: olive oil influences the absorption of dietary lutein and its accumulation in adult rats

This study determined the lutein level in various green leafy vegetables (GLVs) and the influence of olive and sunflower oils on the postprandial plasma and eye response of dietary lutein in adult rats, previously induced with lutein depletion (LD). Fresh GLVs (n = 35) were assessed for lutein (L) and its isomer zeaxanthin (Z) levels by high-performance liquid chromatography and liquid chromatography-mass spectrometry. Among GLVs analyzed, Commelina benghalensis L. contained a higher level of L + Z (183 mg/100 g dry wt) and was used as a lutein source for feeding studies. Rats with LD were fed a diet containing powdered C. benghalensis (2.69 mg lutein/kg diet) with either olive oil (OO group), sunflower oil (SFO group), or groundnut oil (GNO group) for 16 days. The L + Z levels of the OO group were markedly (p > 0.05) higher than those of SFO and GNO groups, in plasma (37.6 and 40.9%) and eyes (22.7 and 30.8%), respectively. These results suggest that oleic acid or OO can be used as a suitable fat source to modulate the absorption of dietary lutein to manage age-related macular degeneration.     

锌胁迫对菖蒲抗氧化酶活性和富集特性的影响

试验研究了不同Zn~(2+)浓度(0,100,200,500,1000 mg kg~(-1))对菖蒲的外部形态和体内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)3种抗氧化酶随土壤中Zn~(2+)浓度的变化以及菖蒲对土壤中Zn~(2+)富集效果。结果表明:(1)在处理浓度Zn~(2+)200 mg kg~(-1)时,三种酶的活性与对照值相比有明显的提高,植株未出现明显的外伤症状,叶片中叶绿素含量上升,未对菖蒲表现出明显的负面影响;(2)当Zn~(2+)200 mg kg~(-1)时三种酶的活性开始出现下降,下降程度与受污染的程度正相关,菖蒲出现明显外伤症状并加剧,叶片叶绿素含量不断下降,叶片中丙二醛(MDA)和脯氨酸的含量不断上升,细胞质膜透性逐渐增加。(3)菖蒲体内Zn~(2+)含量的分布规律均为根(地下部分)茎、叶(地上部分),菖蒲各器官Zn~(2+)浓度随着处土壤浓度增加而升高。(4)四种土壤酶活性都随着Zn~(2+)浓度的增加而不断下降。菖蒲可用于轻度锌污染土壤修复。     

Quantitative liquid chromatographic method using fluorescence detection for determining zearalenone and its metabolites in blood plasma and urine

The liquid chromatographic (LC) method described, suitable for use with both blood plasma and urine, is applicable for determination of zearalenone and alpha-zearalenol at levels as low as 0.5 ng/mL plasma and 5 ng/mL urine. The sample is incubated overnight with beta-glucuronidase to analyze for both conjugated and unconjugated forms of zearalenone. The next day, the sample is acidified with H3PO4, extracted with chloroform, and evaporated to dryness. The residue is dissolved in toluene and loaded onto a silica gel cartridge which is washed with toluene and eluted with toluene-acetone (88 + 12). The eluate is evaporated, and the residue is dissolved in chloroform, extracted with 0.18M NaOH, neutralized with H3PO4, and re-extracted with chloroform. The chloroform extract is evaporated, dissolved in mobile phase for LC, and injected onto a normal phase column under the following chromatographic conditions: mobile phase of water-saturated dichloromethane containing 2% 1-propanol, and fluorescence detector, excitation wave-length 236 nm, and 418 nm cut-off emission filter. Recoveries of zearalenone and its metabolites from blood plasma and urine are 80-89% in the range 2.0-10 ng standard/mL plasma, and 81-90% in the range 10-30 ng standard/mL urine. This method was used to analyze blood and urine samples from a pig fed zearalenone-contaminated feed (5 mg/kg), corresponding to 80 micrograms/kg body weight. Zearalenone was rapidly metabolized to alpha-zearalenol, which appeared in the blood only 30 min after feeding. Almost all zearalenone and alpha-zearalenol was found conjugated with glucuronic acid in both blood plasma and urine.     

Fe3+和Na+共存对缺氧污泥脱氮除磷效率和胞内外聚合物的影响

为了提高多种金属离子共存的含盐废水脱氮除磷效率和生物絮凝性,考察Fe^3+和Na^+共存对A2O工艺缺氧区污染物去除率的影响,研究缺氧区胞内聚合物(Intracellular Polymeric Substances,IPS)和胞外聚合物(Extracellular Polymeric Substances,EPS)的变化,采用气相色谱法与蒽酮比色法分析IPS中聚-β-羟丁酸(Poly-β-hydroxybutyrate,PHB)和糖原含量的变化,结合三维荧光光谱(Three-dimensional Excitation Emission Matrix Fluorescence Spectroscopy,3D-EEM)与傅里叶变换红外光谱(Fourier Transform Infrared Spectroscopy,FTIR)探索EPS组成结构的变化,以期揭示共存的Fe^3+和Na^+、IPS及EPS与污泥絮凝性的关系。结果表明:1)单一Fe^3+的加入有助于提高COD、TN和TP的去除率,增加碱性磷酸酶与酸性磷酸酶活性,IPS和EPS总量增多。2)在Fe^3+和Na^+共存的条件下,当Fe^3+浓度为10 mg/L、Na^+浓度为0.5 g/L时,低浓度的Na^+提高了COD、TN和TP去除率,增强了碱性磷酸酶与酸性磷酸酶活性,增加了IPS总量,但是抑制了微生物EPS的分泌,EPS总量下降;当Fe^3+为10 mg/L,Na^+浓度(>1 g/L)继续升高时,高浓度的Na^+导致COD、TN和TP去除率下降,IPS总量降低,但是促进了微生物EPS的分泌,EPS总量增加。3)由FTIR分析可知,Fe^3+和Na^+浓度的变化并未导致松散结合型胞外聚合物(Loosely Bound Extracellular Polymeric Substances,LB-EPS)和紧密结合型胞外聚合物(Tightly Bound Extracellular Polymeric Substances,TB-EPS)的官能团发生明显变化,主要成分始终为蛋白质(Protein,PN)和多糖(Polysaccharide,PS);由3D-EEM分析可知,Fe^3+的加入使三维荧光光谱中出现了可见区类色氨酸峰,Na^+的加入使色氨酸、腐殖酸类物质降解,EPS的成分改变。4)IPS和EPS之间存在竞争生长,IPS/EPS比值较高时,IPS占主导作用,污泥絮凝性能好。     

甲氰胺混配乳油对柑桔全爪螨的药效试验及联合毒力测定

由甲氰菊酯（灭扫利）和水胺硫磷复配而成的22％甲氰胺混配乳油，其稀释3000～4000倍液，对柑桔全爪螨（Panonychuscitri）有良好的防治效果，室内药效达99．38％～100％。田间药效为94．70％～100％。室内毒力测定结果，甲氰胺混配乳油的LC50为21．02mg／L，灭扫利的为28.75mg／L，水胺硫磷的为153.62mg／L，甲氰胺的毒力显著高于两种单体；共毒系数达205.79，表现出显著的增效作用。