桑色素荧光分光光度法测定水和保健饮料中痕量锗

本文提出了测定水和保健饮料中痕量锗的桑色素荧光分光光度法。检出限分别为0.2μg/L和0.7μg/L,线性范围分别为1.0～25μg/L和5.0～30μg/L,平均回收率分别为97.2％～104.5％和98.8％～104.8％,相对标准偏差分别为3.66％。2.87％方法简便,准确高度,精密度好,共存离子干扰小。     

Optimization of the composition and pH of the mobile phase used for separation and determination of a series of quinolone antibacterials regulated by the European Union

Summary To ensure the safety of human food the European Union (EU) has set tolerance levels for quinolone compounds in animal products, so screening and confirmatory analytical methods are required for monitoring of these drugs. In this work, the proportion of organic modifier and the pH of acetonitrile-water mixtures used as mobile phases were optimized for separation of a group of quinolones. Linear solvation energy relationship (LSER) formalism based on the single solvent polarity parameterE _T ^N was used to predict the chromatographic behaviour of the compounds as a function of the amount of acetonitrile in the mobile phase. Correlation between retention and the pH of aqueous-organic mobile phases has also been used to optimize mobile-phase pH. The optimized mobile phase was a linear gradient starting from 18∶82 (v/v) acetonitrileacetate + formate buffer, pH 2.5. Quality data were determined and were satisfactory. The method detection limit was approximately 10 ng mL⁻¹ for most of the quinolones studied. The proposed mobile phase is compatible with mass spectrometric detection of the substances.     

Capillary gas chromatography of metal chelates of diethyl dithiocarbamates

Summary Capillary GC of metal chelates of diethyl dithiocarbamate (DDTC) was examined on a methylsilicone DB-1 column, (25 meter, 0.2 mm. i.d) with a film thickness of 0.25 μm. Elution was carried out at the initial column temperature of 180°C and programmed at 5°C min⁻¹ to 260°C. Detection was by FID or ECD. Symmetrical peaks with base line separation were obtained with the metal chelates of copper(II), nickel(II), cobalt(III), manganese(II) and chromium(III). The ECD gave better sensitivity than the FID with a linear calibration range of 5–50 μg mL⁻¹ and detection limits 2.0–6.0 μg mL⁻¹, corresponding to 111–333 pg of metal ion reaching the detector. The method was applied to the determination of metal ions in water and pharmaceutical preparations with a coefficient of variation (CV) within 4.0%. When compared with a standard flame AAS method the results revealed no significant difference.     

Simultaneous determination of quinolone antibacterials in bovine milk by liquid chromatography-mass spectrometry

A new liquid chromatography-mass spectrometry (LC-MS) method has been developed and validated for the simultaneous determination of eight quinolone antibacterials for veterinary use in processed bovine milk samples. The quinolones studied included marbofloxacin, ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid and flumequine. Also, a new sample-treatment procedure was used for extraction and preconcentration of these compounds. It involved defatting by centrifugation, protein precipitation by adding a mixture of glacial acetic acid-acetonitrile and removing acetonitrile with dichloromethane; finally, the acidified aqueous layer was evaporated to dryness in a speed vac system, resuspended in the mobile phase and filtered prior to LC injection. The mobile phase was composed of a formic acid aqueous solution 0.1% (v/v) and acetonitrile, with an initial composition of water-acetonitrile 95: 5 (v/v) and using linear gradient elution. Norfloxacin was used as internal standard. The limits of quantification found (2-7 ng g(-1)) were in all cases lower than the maximum residue limits tolerated by the European Union for these compounds in milk.     

2，3－二氨基萘荧光分光光度法测定环境水样中的痕量亚硝酸盐

本文描述了用２，３－二氨基萘荧光分光光度法测定水样中亚硝酸盐的最佳测定条件，并测定了井水和湖水中的亚硝酸盐。测定样品的检出限为０．４μｇ／Ｌ，线性范围是１．０～１５００μｇ／Ｌ，相对标准偏差为１．６％，加标回收率为９５％～１０６％。本法简便、快速，准确度高，共存离子干扰小，样品无须萃取步骤。     

Potential of ethylenediaminedi(o-hydroxyphenylacetic acid) and N,N'-bis(hydroxybenzyl)ethylenediamine-N,N'-diacetic acid for the determination of metal ions by capillary electrophoresis

Two aromatic polyaminocarboxylate ligands, ethylenediaminedi(o-hydroxyphenylacetic acid) (EDDHA) and N,N′-bis(hydroxybenzyl)ethylenediamine-N,N′-diacetic acid (HBED), were applied for the separation of transition and heavy metal ions by the ion-exchange variant of electrokinetic chromatography. EDDHA structure contains two chiral carbon centers. It makes it impossible to use the commercially available ligand. All the studied metal ions showed two peaks, which correspond to meso and rac forms of the ligand. The separation of metal–HBED chelates was performed using poly(diallyldimethylammonium) polycations in mixed acetate–hydroxide form. Simultaneous separation of nine single- and nine double-charged HBED chelates, including In(III), Ga(III), Co(II)–(III) and Mn(II)–(III) pairs demonstrated the efficiency of 40 000–400 000 theoretical plates. The separation of Co(III), Fe(III) complexes with different arrangements of donor groups and oxidation of Co(II), Mn(II), Fe(II) ions in reaction with HBED have been discussed.     

表面活性剂胶束增敏亚水杨基-邻-氨基苯酚荧光光度法测定镓

本文研究了亚水杨基-邻-氨基苯酚镓配合物在不同pH及各种表面活性剂胶束介质中的荧光性质。结果表明,在pH 4.25的盐酸/乙酸钠缓冲液中,十二烷基硫酸钠可使配合物的荧光强度增加两倍,线性范围为0.1～5μm镓。本法用于人工合成样中镓的测定,结果满意。     

Separation selectivity of some ethylenediaminetetraacetic acid and cyclohexane-1,2-diaminetetraacetic acid complexes in column and ion electrokinetic chromatography

The complexes of Mn²⁺, Cd²⁺, Fe³⁺, Pb²⁺, Ni²⁺, Co²⁺, Zn²⁺ and Cu²⁺ with EDTA and cyclohexane-1,2-diaminetetraacetic acid (CDTA) were separated and detected in column and ion electrokinetic chromatography with suppressed conductivity and direct UV detection, respectively. In column ion chromatography (IC) these complexes were separated on an IonPac AS4A anion-exchange column (Dionex, USA). Parameters of carrier electrolyte, which were examined in the ion electrokinetic chromatography (IEKC) mode, include polymer and sulfate concentrations. In IEKC separation selectivity of complexes with poly(diallyldimethylammonium) cation as modifier is similar as for an IonPac AS4A column both for EDTA and CDTA chelates. It was shown that the ion-exchange capacity of the electrokinetic system is more than 100-times lower than the capacity of the IC column for the same peak resolution. In comparison with column main advantages of electrokinetic version are high separation efficiency (220 000–390 000 theoretical plates) and the absence of the analyte interaction with the sorbent matrix.     

Detection of metal ions by glass capillary gas-chromatographic separation of their volatile chelates

The utility of several glass capillary columns to separate some trifluoroacetonates, diethyldithiocarbamates, di(trifluoroethyl) dilithiocarbamates and diisopropyldithiophosphates metal chelates was investigated. The increased sensitivity offered by selective detectors was also explored. Most favorable results were obtained with a short highly inert fused silica column, coated with a non-retentive liquid phase.     

TBP萃淋树脂色谱分离荧光分析法测定岩矿中痕量铟

本文研究了８—羟基喹啉—５—磺酸荧光法测定铟，在增效试剂ＣＴＭＡＢ存在下，提高了反应的灵敏度，铟在４—１２０ｎｇ／ｍＬ范围内与△Ｆ值呈良好的线性关系，检出下限为４ｎｇ／ｍＬ，其相对标准偏差为０．９４％，本法采用ＴＢＰ萃淋树脂色谱法分离和富集干扰后，可用于地质试样中铟的测定。     

Review: recent advances in the chemistry of metal chelate monomers

This review summarizes recent advances in the chemistry of metal chelate monomers. Depending on the character of bonding of the metal to the chelating fragment, metal chelate monomers are divided into four main types: molecular metal chelates, intracomplex compounds, macrocyclic complexes, and polynuclear metal chelates. The synthetic methodologies for preparing metal chelate monomers are systematized. Special attention is paid to the effect of a metal on both the polymerization transformations of the metal chelate monomers and properties of the products formed. The bibliography includes papers published after 2010.     

高效液相色谱法同时检测8种喹诺酮类兽药残留量

建立了吡哌酸、氧氟沙星、环丙沙星、单诺沙星、恩诺沙星、沙拉沙星、(噁)喹酸和氟甲喹8种喹诺酮类兽药残留量的高效液相色谱-荧光检测方法. 方法的线性范围: 30～2000 μg/kg, 定量限为30 μg/kg, 检出限为5 μg/kg (吡哌酸为20 μg/kg). 该方法采用基质分散和微波萃取技术进行样品的前处理, 回收率为70.0%～99.5%, 相对标准偏差1.0%～8.5%. 并同固相萃取方法进行了比较, 分别使用了RPS、HLB、MAX 3种固相萃取柱, 其回收率均低于本法. 确立了以Aglient XDB-C18 (5 μm, 150 mm×4.6mm i.d.)色谱柱, H3PO4-纯水-三乙胺-乙腈(pH 3.0)为流动相的最佳色谱条件, 吡哌酸、氧氟沙星、环丙沙星、单诺沙星、恩诺沙星、沙拉沙星的检测波长为: 激发波长285 nm, 发射波长460 nm;(噁)喹酸和氟甲喹为: 激发波长325 nm, 发射波长365 nm. 方法可满足兽药残留检测要求.     

Synthesis of chiral amino acids with metal ion chelating side chains from l-serine using Negishi cross-coupling reaction

The scope of the Negishi cross-coupling reaction of organozinc compounds derived from chiral amino acids was extended to electron rich iodoanilines and iodobenzylamines as coupling reagents. The protocol allows the direct modification of serine into phenylalanine derivatives bearing metal ion chelating ligands in their side chain, such as amino esters 6 and 7. The preparation of metal complex labeled peptides, the construction of synthetic receptors and hybrid materials are potential applications of the modified chiral amino acids.     

A novel intumescent flame-retardant system containing metal chelates for polyvinyl alcohol

A novel flame retardant containing phosphorous-nitrogen structure, the ammonium salt of 2-hydroxyl-5,5-dimethyl-2,2-oxo-1,3,2-dioxapho sphorinane (PNOH), was synthesized and its structure was characterized by ¹H NMR and FTIR spectra. PNOH was used together with ammonium polyphosphate (APP) to prepare a novel intumescent flame retardant (IFR) for polyvinyl alcohol (PVA). When a few amounts (0.5%) of metal chelates were added, the flame retardancy of the IFR-PVA systems was significantly improved, having a high LOI value of 34.2 in a total IFR loading of 15 wt.%. In order to have an understanding of the resulting flame retardant effects, the thermal degradation behaviors of IFR-PVA systems were investigated by thermogravimetric analysis (TGA), and the morphology and structures of residues generated in different conditions were investigated by scanning electronic microscopy (SEM) and FTIR spectra. The results show that NiSAO can promote the thermal stability of the IFR-PVA; the residual char containing polyphosphoric or phosphoric acid is formed during the combustion; the formation of a continuous and dense char layer could inhibit the transmission of heat during contacting with flame and shows good flame retardancy.     

Trace enrichment of (fluoro)quinolone antibiotics in surface waters by solid-phase extraction and their determination by liquid chromatography-ultraviolet detection

A new and simple analytical methodology for the simultaneous analysis of acidic and zwitterionic (fluoro)quinolones in surface waters at trace concentration level is presented. The method is based on the preconcentration of these analytes by a solid-phase extraction procedure and their subsequent quantification by liquid chromatography using ultraviolet detection. The breakthrough volumes of the selected (fluoro)quinolones in four different sorbents--C18, styrenedivinylbenzene (SDB), C18-cation-exchange and SDB-cation-exchange--have been evaluated and varied between 25 and 150 ml depending on the antibiotic and the sorbent used. An exhaustive study of the influence of sample pH on the preconcentration step has been carried out in order to find a suitable procedure for extraction of acidic and zwitterionic FQs in one single step. Under optimum conditions, it was possible to percolate up to 250 ml of water solution onto both C18 and SDB-cation-exchange cartridges with quantitative recoveries for all the analytes tested. However, matrix components of the surface water samples analysed negatively affected the recoveries of the analytes in the SDB-cation-exchange cartridge and thus, C18 cartridges were finally selected for the analysis of the (fluoro)quinolones in lake and river water. The limits of detection achieved with this procedure varied between 8 and 20 ng l(-1) proving its suitability for the determination of the (fluoro)quinolones in water samples at a realistic environmental concentration level.