LC-MS-MS测定河口及近岸海水中的氟喹诺酮类药物

建立了河口及近岸海水中氟喹诺酮类药物残留的固相萃取富集-高效液相色谱-串级质谱测定方法.以Waters HLB固相萃取（SPE）小柱富集水样中的氟喹诺酮类药物,用XDB-C18柱、乙腈、甲酸（体积分数为0.2%）水流动相进行分离,ESI正离子源、三重串级质谱及多反应监测模式（MRM）进行目标物的定性、定量测定.优化实验条件下,方法的检出限（3σ）为0.002～0.010μg/L,定量限（10σ）为0.010～0.050μg/L,样品加标回收率为73.3%（奥比沙星）～119.7%（氧氟沙星）,相对标准偏差（RSD）为1.3%～5.8%（2.5μg/L,n=6）.     

云南野生黄牡丹花色素成分的鉴定

以云南野生黄牡丹为材料,通过特征显色反应、紫外—可见光谱扫描及高效液相色谱—质谱技术(HPLC-MS)对其花瓣中的色素成分进行了初步分析和鉴定.结果表明,黄牡丹花色素的组成包括类黄酮和叶绿素两大类,其中类黄酮类色素主要为查耳酮和黄酮、黄酮醇的混合物,包括2’,4’,6’,4-四羟基查耳酮(2’,4’,6’,4-tetr...     

RP-HPLC法测定细叶杜香叶中4种活性成分的质量分数

为了建立测定细叶杜香叶中秦皮乙素、秦皮素、金丝桃苷和槲皮素质量分数的方法,采用反相高效液相色谱法(色谱条件:色谱柱为Inertsil ODS-SP(5 μm,4.6mm×250 mm,柱号:9K192609)、流动相为V甲醇)∶V(0.2%醋酸)=43∶57、流速1.0 mL·min-1、检测波长350 nm),测得秦...     

毛细管气相色谱法测定唑草酮在甘蔗及其土壤中的残留量

为建立唑草酮在甘蔗及其土壤中残留的分析方法,用甲醇∶水=4∶1(v/v)溶液提取甘蔗及其土壤中的唑草酮,然后用石油醚∶二氯甲烷=4∶1 (v/v)萃取.石油醚和二氯甲烷相经浓缩后过弗罗里硅土桂净化,毛细管柱分离,用微池电子捕获检测器(μECD)测定.结果表明:唑草酮在0.005～1.00μg/mL范围内线性良好,线性相关系数(r)为0.9990.该方法对唑草酮的最小检出量为1.0×10-12 g,唑草酮在甘蔗植株和土样的最低检测浓度均为0.001 mg/kg,对甘蔗及其土壤空白样本的平均添加回收率为88.59％～ 102.74％,相对标准偏差为1.77％～5.39％.该方法符合农药残留分析的要求,具有操作简单、净化分离效果好、检测灵敏度高特点.     

径向流色谱分离技术原理及应用分析

径向流色谱法是一种新型色谱分离纯化技术,采用径向流动特殊设计,在生物、食品领域应用逐渐广泛,与传统的轴向色谱相比,该方法具有流速高、操作压力低、线性放大容易及样品处理量大等突出优势。文中针对径向流色谱分离技术原理和特点作了详细论述,并简介了该技术的应用及发展前景。     

Rapid quantification of Bacillus subtilis antibiotics in the rhizosphere

Biological control agents like Bacillus subtilis offer an alternative and supplement to synthetic pesticides. Antibiotic production by biocontrol strains of B. subtilis can play a major role in plant disease suppression. Our current understanding of B. subtilis antibiosis comes from culture media measurements of antibiotic production and in vitro suppression of pathogens. Quantifying the antibiotic metabolite chemistry of B. subtilis biofilms growing on root surfaces provides a more accurate understanding of in vivo antibiotic production. An analytical method based on solid-phase extraction (SPE) with high-performance liquid chromatography (HPLC) and mass spectroscopy (MS) has been developed to quantify antibiotics produced by B. subtilis growing on plant roots. Cucumber (Cucumis sativus) was grown in composted soil and potting media inoculated with B. subtilis strain QST 713 (AgraQuest, USA). Two important B. subtilis antibiotics, surfactin and iturin A, were extracted from root and rhizosphere soil using acidified organic solvents followed by cleaning and concentration using SPE. HPLC and HPLC-MS were used to measure surfactin and iturin A. Rhizosphere concentrations of both antibiotics increased with plant age. For plants grown in peat-based potting media, surfactin concentrations increased from 9 μg g⁻¹ root fresh weight (RFW) at 15 d to 30 μg g⁻¹ RFW at 43 d. Iturin concentrations were 7 μg g⁻¹ RFW at 15 d and 180 μg g⁻¹ RFW at 43 d. In an initial field trial in a composted fine sandy loam, we demonstrated rhizosphere production of surfactin and iturin under competition and predation by the myriad macro- and microfauna existing in a fertile high-organic soil, with mature B. subtilis-inoculated cucumber roots yielding 33 μg g⁻¹ RFW surfactin and 630 μg g⁻¹ RFW iturin at 78 d.     

Spectroscopic properties of humic acids isolated from the rhizosphere and bulk soil compartments and fractionated by size-exclusion chromatography

The humic acids (HAs) isolated by conventional procedure from rhizosphere (r) and bulk (c) soils were analyzed by means of chemical and physico-chemical techniques. Two different crops were selected, tomato (T) and artichoke (A), and each HA was fractionated by size-exclusion chromatography (SEC) into three fractions with increasing molecular size, respectively, Fraction I (FrI) < Fraction II (FrII) < Fraction III (FrIII). Elemental analysis data indicated greater N and S contents in the rhizosphere T-HAs, with respect to rhizosphere A-HA, which suggests the occurrence in the former ones of a large amount of organic nitrogen- and sulfur-containing compounds that are released by the rhizodeposition processes. Further, the three HA fractions from the bulk soils of the two series showed a gradual increase of C, H, and N contents, and a decrease of O and S contents and C/N and C/H ratios. These results suggested that the lowest molecular size fractions are richer in oxygenated functional groups, whereas the higher molecular size fractions are richer in N-containing groups and structural C- and H-containing units. The three HA fractions from the rhizosphere soils of the two series showed a gradual decrease in C content, and an increase of H, N, and O contents, which suggests the possible incorporation into soil HAs of a multitude of C-containing compounds of low molecular size released by plant roots. The FT-IR data, in general, suggested that the contents of carboxylic, phenolic and N-containing groups and polysaccharide-like components in HAs from rhizosphere soils are larger than those of HAs from the corresponding bulk soils. Further, the FrI fraction consisted mainly of simple structural units, likely quinonic and phenolic units with a prevalent aromatic character, whereas the FrII and, especially, FrIII fractions featured a mixed aliphatic/aromatic nature and a greater molecular complexity. The extent of these differences appeared to depend on the plant species and age, and is mainly due to the partial incorporation into rhizosphere HAs of typical root exudate components, such as amino acids, amides, aliphatic and aromatic acids of low molecular size, polysaccharides and sugars, fatty acids and sterols, and enzymes.     

Metabolite profiling of spinach (Spinacia oleracea L.) leaves by altering the ratio of in the culture solution

To observe the effect of different forms of N, we have applied metabolic profiling using gas chromatography mass spectrometry to evaluate the metabolite composition of spinach. The aim of the present study was to find an appropriate indicator of overall metabolic response to N source. The effect of the     ratio on spinach tissue was investigated, comparing two cultivars that differed in their ability to use N. There was wide variation in     absorption without any distinct growth inhibition in either cultivar. Statistical analysis revealed that the metabolites could be broadly divided into two types, correlating either positively or negatively with     uptake in the culture solution. Principal component analysis (PCA) was an effective tool that extracted the indexes of the effect of the ratio of N forms as PCA scores. Close relationships between metabolite profiles and     uptake were observed, indicating that metabolic profiling is able to distinguish the invisible metabolic change in mature leaves of spinach and may provide a new tool for the investigation of quality features or rhizosphere nutritional condition.     

Fractionation of metal complexes with dissolved organic matter in a rhizosphere soil solution of a humus-rich Andosol using size exclusion chromatography with inductively coupled plasma-mass spectrometry

To better understand the behavior of metals in soil–plant systems, their physicochemical forms in rhizosphere soil should be elucidated. The dissolved organic matter (DOM) in a soil solution influences the mobility and bioavailability of metals in soil. The present study examined the effects of plant growth on DOM–metal complexes in a rhizosphere soil solution using size exclusion chromatography combined with an inductively coupled plasma-mass spectrometer system (SEC–ICP-MS) and an ultrafiltration technique. Humus-rich volcanic ash soil from the surface of an agricultural field was used in a pot cultivation experiment. Brassica rapa nothovar. was cultivated in a pot in which rhizosphere soil (R) was separated by a nylon net screen from non-rhizosphere soil (NR). Soil solutions were collected using a high-speed centrifugation method 3 weeks after sowing and analyzed using SEC–ICP-MS. Some peaks of DOM with a high molecular size were detected in the ultraviolet-absorbing chromatograph (280 nm) of the soil solution samples. Their concentrations were much higher in the R solution than in the NR solution. Metals including Al, Fe, Cu, Zn, Pb, Y, La and U were detected at the ultraviolet peak positions of the DOM. The ultrafiltration experiment showed that the size distributions of the organic materials to which the metals were combined differed between the R and NR soil solutions. These results suggest that plant growth enhanced the dissolution of metals adsorbed with organic matter from the solid phase in rhizosphere soil.     

不同种源鱼腥草中槲皮素变异规律

为了揭示鱼腥草Houttuynia cordata种质资源中槲皮素量变异规律,为鱼腥草优良品种选育奠定基础,用高效液相色谱法测定22个种源鱼腥草中槲皮素的质量分数,并分析植物形态特征、地理位置和生长性状与槲皮素质量分数的关系。结果表明,不同种源鱼腥草中槲皮素的质量分数存在显著差异,与植物形态存在一定的关系,与植株高度显著相关,与地理位置和植株地径没有显著的相关性。鱼腥草种质资源槲皮素的质量分数存在一定的变异规律。针对鱼腥草中槲皮素选择新品种时,应重点考虑鱼腥草植株的形态特征和植株高度。