Analytical Chemistry Research

In this paper, we describe a simple method for sampling, pre-concentrating, and separating volatile and semi-volatile components from two different cave atmospheres. Sampling is performed by capturing a volume of cave atmosphere in a Tedlar bag or Suma canister for sample storage and transport back to the laboratory. Loading a portion of the sample on a multi-bed sorption trap allows for sample pre-concentration prior to separation and detection of components on a comprehensive two-dimensional gas chromatograph (GC×GC). Comparison of two Texas caves reveals the power of comprehensive two-dimensional gas chromatography (GC×GC) for volatile separation and detection, and to our knowledge marks the first use of GC×GC for the analysis of cave atmospheres. Analysis of the results revealed 138 and 146 chromatographic signals over an S/N threshold of 500 and direct comparison of the two samples revealed 50 identical chromatographic signals. This study is a first step toward demonstrating the ability of GC×GC to separate the complex volatiles and semi-volatiles in the cave atmosphere as a fingerprinting tool.

Ryan C. Blase

Edward L. Patrick

Joseph N. Mitchell

Mark Libardoni

Analysis of cave atmospheres by comprehensive two-dimensional gas chromatography (GC×GC) with flame ionization detection (FID)

综合二维气相色谱-火焰离子化检测法对洞穴大气成分的分析

Heparin is a linear sulfated polysaccharide widely used therapeutically as an anticoagulant. It is also the starting material for manufacturing low-molecular-weight heparins (LMWH). Quality control of heparin and LMWH is critical to ensure the safety and therapeutic activity of the final product. However due to their complex and heterogeneous structure, orthogonal analytical techniques are needed to characterize the building blocks of heparin. One of the state-of-the-art methods for heparin analysis is based on complete enzymatic digestion using a mixture of heparinases I, II, and III, followed by the separation of the resulting oligosaccharides by liquid chromatography. The European Pharmacopoeia strong anion-exchange chromatographic method, used to quantify 1,6-anhydro derivatives in enoxaparin, is here applied to the analysis of the heparin building blocks. Their quantification, namely the determination of their average w/w percentage in the heparin chain, is obtained after identification of all components including glycoserine derivatives and 3-O sulfated di- and tetrasaccharides. This work therefore provides a comprehensive overview of the building blocks of unfractionated heparin, including those chemically modified by the manufacturing process, either within the polysaccharide chain or at its reducing end.

Pierre Mourier

Pascal Anger

Céline Martinez

Fréderic Herman

Christian Viskov

Quantitative compositional analysis of heparin using exhaustive heparinase digestion and strong anion exchange chromatography

利用彻底肝素酶消化和强阴离子交换色谱法对肝素的定量成分分析

A simple, sensitive and rapid liquid chromatographic method was developed and validated for the analysis of flunixin meglumine (flunixin-M) in bulk, pharmaceutical dosage forms, bovine liver and kidney. Analytical separation was performed in less than 4 min using a C18 column with UV detection at 284 nm. A micellar solution composed of 0.15 M sodium dodecyl sulphate, 8% n-butanol and 0.3% triethylamine in 0.02 M phosphoric acid buffered at pH 7.0 was used as the mobile phase. The method was fully validated in accordance with the International Conference on Harmonization (ICH) guidelines. The limit of detection and the limit of quantitation were 0.02 and 0.06 μg mL−1, respectively. The recoveries obtained were in range of 95.58–106.94% for bovine liver and kidney. High extraction efficiency was obtained without matrix interference in the extraction process and in the subsequent chromatographic determination. The method showed good repeatability, linearity and sensitivity according to the evaluation of the validation parameters.

Fathalla F. Belal

Sawsan A. Abd El-Razeq

Manal M. Fouad

Fatma A. Fouad

Micellar high performance liquid chromatographic determination of flunixin meglumine in bulk, pharmaceutical dosage forms, bovine liver and kidney

微乳高效液相色谱法测定原料药、制剂、牛肝和牛肾中的氟尼辛葡甲胺

A cobalt(II) porphyrin was successfully incorporated into polymer membranes for the optical sensing of imidazole and its derivatives. This research has led to a better understanding of the behavior of Co(II) porphyrin in solution and in polymeric membranes. In aprotic dichloromethane (DCM), the Co(II) tetraphenylporphyrin (CoTPP) and Co(II) octaethylporphyrin (CoOEP) show a sensitive response to imidazole due to the strong ligation of the N-3 on the imidazole ring to the Co(II) center, which induces an absorbance change to the Soret band. However, when doped in polymeric films, only the CoTPP exhibits moderate sensitivity towards aqueous imidazole, histamine and histidine. This weakened coordination ability of CoTPP towards imidazole in the polymer films may be due to the coordination of the plasticizer, the impurities from the THF and polymer matrix at the Co(II) center. The selectivity of the polymer films towards imidazole over common anions is high. Lifetime of the cobalt(II) porphyrin incorporated polymer film was relatively short.

Yueyang Tan

Nicole Escorcia

Alison Hyslop

Enju Wang

Investigation of cobalt porphyrin doped polymer membrane films for the optical sensing of imidazole and its derivatives

掺杂钴卟啉聚合物膜薄膜对咪唑及其衍生物的光学传感研究

A simple, ultra sensitive and selective method for the spectrophotometric determination of Ir3+ in various synthetic and environmental samples was reported. The analyte ions were collected on a membrane filter in the form of their red complex with 5-(2-benzothiazolyl-azo)8-hydroxy-quinoline (BTAHQ), and the absorption spectra of the colored membrane filters were acquired. Effects of pH value, sample volume, and amount of BTAHQ were examined in order to optimize sensitivity. The interference by common other ions was eliminated using appropriate masking agents. The absorbance is linearly related to the concentration of Ir3+ in the ranges from 0.1 to 0.8 μg/L, and from 1.0 to 7.0 μg/L, respectively, the correlation coefficients (R2) being 0.9996 and 0.9994. The molar absorptivities were calculated to be 4.81 × 105 and 4.26 × 107 L mol−1 cm−1 at 563 nm, whereas Sandell sensitivity was found as 0.391 and 0.004 ng cm−2, respectively. The novelty and advantages of the proposed method is the highly sensitivity of the proposed method compared with all previously cited methods for iridium determination. Under the optimal conditions, the detection limit is 0.03 μg/L. The recoveries in case of spiked samples are between 98.7% and 101.5%, and the relative standard deviations range from 1.21% to 1.75%.

A.S. Amin

I.A. Zaafarany

Spectrophotometric determination of iridium after complexation and membrane filtration

分光光度法测定铱的络合及膜过滤后测定

A simple, rapid and sensitive method for the determination of atorvastatin calcium in pharmaceutical preparations using two modified carbon paste electrodes was developed. One electrode (sensor A) is based on ion-pair of atorvastatin with 5,6-diaminouracil hydrochloride (ATS-DAUH) and the other (sensor B) is based on atorvastatin with picric acid (ATS-PC). Among three different solvent mediators tested, dioctylphthalate (DOPH) exhibited a proper behavior including Nernstian slopes of the calibration curve at 58.76 ± 0.8 and 57.48±1 mV per decade for sensors A and B. The response times were 10 and 12 s, detection limits 1.3 × 10−6 and 2.2 × 10−6 M; the concentration range 2.5 × 10−6-7.9 × 10−2 M and 3.0 × 10−6 to 7.9 × 10−2 M respectively. The present electrodes show good discrimination of atorvastatin calcium from several inorganic, organic ions, sugars and some common excipients. The sensors were applied for the determination of atorvastatin calcium in pharmaceutical preparations using standard addition and the calibration curve methods. The results obtained were satisfactory with excellent percentage recovery comparable and sometimes better than those obtained by other routine methods for the assay. The proposed potentiometric methods offer the advantages of simplicity, accuracy, automation feasibility and applicability to turbid and colored sample solutions.

Salwa Fares Rassi

Chemically modified carbon paste ion-selective electrodes for determination of atorvastatin calcium in pharmaceutical preparations

化学修饰碳糊离子选择电极用于制药制剂中阿托伐他汀钙的测定

Faiz Bukhari Mohd Suah

Preparation and characterization of a novel Co(II) optode based on polymer inclusion membrane

基于聚合物包埋膜的新型Co(II)光学传感器的制备与表征

In this work, Ni/Ni nanoparticles were immobilized on modified nanoclay then, the resultant nanocomposite was used as a sorbent for separation of dibenzothiophene. The concentration of dibenzothiophene was determined with UV–vis spectrophotometry at 287 nm. Different parameters affecting the separation of dibenzothiophene such as: the ratio of Ni/NiO nanoparticles to nanoclay, amounts of Ni/NiO nanoparticles and nanoclay, stirring time of dibenzothiophene solution on the sorbent, type of eluent, eluent volume, elution time, stirring time for preparing the sorbent were optimized. The obtained results were shown quantitative desorption of dibenzothiophene performed using ethanol as eluent. A linear concentration range of 0.5–15 mg/L was obtained with a detection limit of 0.047 mg/mL. The sorbent capacity was found to be 32 mg/g. Relative standard deviation was ±1.4 for six replicated determination of 5 mg/g of dibenzothiophene. The optimized procedure was successfully used for a crude oil sample.

Amineh Mashkuri

Asma Saljooqi

Zeinab Tohidiyan

Nano clay Ni/NiO nanocomposite new sorbent for separation and preconcentration dibenzothiophene from crude prior to UV–vis spectrophotometery determination

纳米粘土Ni/NiO纳米复合材料：分离和预浓缩二苯并噻吩的新型吸附剂，用于紫外-可见分光光度法测定前的原油处理

Polypyrrole-Sn(IV)arsenotungstate (PPy-SnAT) conductive nanocomposite cation exchange have been synthesized by in-situ chemical oxidative polymerization of polypyrrole with Sn(IV)arsenotungstate (SnAT). PPy-SnAT nanocomposite was characterized by Fourier transform infra-red spectroscopy (FTIR), X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive x-ray (EDX) and thermogravimetric analysis (TGA). The ion exchange capacity (IEC) and DC electrical conductivity of nanocomposite was found to be 2.50 meq/g and 5.05 × 10−1 S/cm respectively. The nanocomposite showed appreciable isothermal stability in terms of DC electrical conductivity retention under ambient condition up to 130 °C. The nanocomposite cation exchange based sensor for detection of formaldehyde and ammonia vapours were fabricated at room temperature. It was revealed that the resistivity of the nanocomposite increases on exposure to higher percent concentration of ammonia and lower concentration of formaldehyde at room temperature (25 °C).

Asif Ali Khan

Rais Ahmad

Mohd. Zeeshan

Comparative sensing of aldehyde and ammonia vapours on synthetic polypyrrole-Sn(IV)arsenotungstate nanocomposite cation exchange material

合成聚吡咯-Sn(IV)砷钨酸盐纳米复合阳离子交换材料对醛和氨蒸气的比较传感

A convenient colorimetric and ratiometric fluorescent probe based on BODIPY derivative for cyanide detection has been synthesized, whose structural contains a dicyanovinyl group used as a sensing unit. Among the tested analytes, such as CN−, F−, Cl−, Br−, I−, ClO4−, AcO−, NO3−, H2PO4− HSO4−, S2− and N3−, only CN− could react with dicyanovinyl moiety by nucleophilic addition, which disrupted the π-conjugation of the probe and hindered the intramolecular charge transfer (ICT), leading a blue shift of absorption and fluorescence spectrum and a concomitant color change from yellow to light pink. The detection limit of this probe was calculated to be 0.98 μM, which is lower than the maximum concentration in drinking water (1.9 μM) permitted by the World Health Organization (WHO). Moreover, the probe showed excellent selectivity and anti-interference ability towards CN− over other anions. The reaction mechanism was fully supported by 1H NMR and MS spectrum.

Yanhua Yu

Tingting Shu

Changzhi Dong

A convenient colorimetric and ratiometric fluorescent probe for detection of cyanide based on BODIPY derivative in aqueous media

基于BODIPY衍生物的水相介质中检测氰化物的便捷比色和比率荧光探针

出版信息	出版商: Elsevier B.V.，出版周期: ，期刊类型: journal，开源期刊: 否
基本数据	创刊年份: 2014，原创研究文献占比: ，自引率:， Gold OA占比:

Analytical Chemistry Research

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