Porous carbon derived from a metal–organic framework as an efficient adsorbent for the solid‐phase extraction of phthalate esters

A porous carbon designated as MOF‐5‐C was prepared by directly carbonizing a metal–organic framework (MOF‐5). The morphology and microstructure of MOF‐5‐C were characterized by scanning electron microscopy, N₂ adsorption, and powder X‐ray diffraction. The MOF‐5‐C retained the original porous structures of MOF‐5, and showed a high Brunauer–Emmett–Teller surface area (1808 m² g^?1) and large pore volume (3.05 cm³ g^?1). To evaluate its adsorption performance, the MOF‐5‐C was used as an adsorbent for the solid‐phase extraction of four phthalate esters from bottled water, peach juice, and soft drink samples followed by high‐performance liquid chromatographic analysis. Several parameters that could affect the extraction efficiencies were investigated. Under the optimum conditions, a good linearity was achieved in the concentration range of 0.1–50.0 ng mL^?1 for bottled water sample and 0.2–50.0 ng mL^?1 for peach juice and soft drink samples. The limits of detection of the method (S/N = 3) were 0.02 ng mL^?1 for bottled water sample, and 0.04–0.05 ng mL^?1 for peach juice and soft drink samples. The results indicated that the MOF‐5‐C exhibited an excellent adsorption capability for trace levels of phthalate esters, and it could be a promising adsorbent for the preconcentration of other organic compounds.     

Liquid chromatographic determination of St. John's wort components in functional foods

A method was developed for determination of St. John's wort marker compounds hypericin, pseudohypericin, hyperforin, and adhyperforin in functional foods. Solid-phase extraction provided analyte extraction and significant sample cleanup prior to analysis using liquid chromatography (LC) with UV and fluorescence detection. In addition to quantification using LC-UV, confirmation was made with electrospray ionization LC mass spectrometry (LC/MS). Several commercially available tea and drink products claiming to contain St. John's wort were tested. Recoveries ranged from 51 to 98% for the liquid samples. Comparison of the concentrations in 4 St. John's wort teas showed a variation in analyte concentration (1044-10 ng/mL marker compounds in brewed tea) and composition. No marker compounds were found in the beverages, indicating possible decomposition of the marker compounds caused by low pH and/or exposure to light. A solvent extraction procedure was developed for analysis of the marker compounds from solid samples. Analytes were detected at low parts per million, with an average recovery of 75%. No St. John's wort components were found in the 2 solid functional food samples analyzed.     

高效液相色谱快速测定草本植物饮料中28种外源性药物和内源性成分

建立了高效液相色谱快速测定草本植物饮料中28种外源性药物和内源性成分的分析方法。样品经甲醇-水（70：30,v/v）超声提取后,使用Thermo Accucore C18色谱柱（100 mm×4.6 mm,2.6 μm）,以甲醇、乙腈和20 mmol/L乙酸铵溶液（pH 4.2）为流动相进行梯度洗脱,流速为1.2 mL/min,柱温为35℃,采用二极管阵列检测器,检测波长为254和220 nm,外标法定量。结果表明,28种成分在1~100 mg/L范围内线性关系良好,相关系数（r）均不小于0.999。液体样品和固体样品的检出限（LODs）分别为1~10和20~200 mg/kg。28种成分在液体和固体样品中的加标回收率分别为88.8%~118.6%和92.7%~112.3%,相对标准偏差（RSDs）分别为0.1%~6.7%和0.1%~6.4%。按上述方法检测草本植物饮料456批,检出阳性样品55批次,检出率为12.1%。该法简便快速、准确可靠,适用于草本植物饮料中28种成分的测定。     

Screening and identification of unknown contaminants in water destined to human consumption: A case study

As a response to a recent emergency case of suspected deliberate contamination of bottled drinking water addressed to sensitive personalities, samples were submitted to our laboratory for investigation; an analytical framework for wide screening and identification of unknown hazardous chemicals and microbiological agents in water has been developed and experienced for the purpose. The proposed approach combines several physico-chemical (inverse-phase liquid chromatography with spectrophotometric or mass spectrometric detection, suppressed ion chromatography, inductively coupled plasma-optical emission spectrometry, gas chromatography with mass spectrometric detection), microbiological (defined substrate technology) and biological assays (viability and macromolecular synthesis of cultured cells), thus allowing the detection of different classes of contaminants (inorganic and organic compounds, metals, algal toxins, bacterial indicators of faecal contamination, enteric pathogens, staphylococci, actinomycetes) and their effects.The application of the developed strategy to the suspected samples did not highlight the presence of specific and considerable risks for human health although a few organoleptic and microbiological parameters were compromised and water was not suitable for human consumption. Therefore, we were able to classify this episode as a water contamination threat instead of confirming an incident.The proposed screening-confirmatory analytical scheme can be a valuable tool for obtaining conclusive and relatively rapid results in investigations concerning accidental or intentional contamination of drinking water.     

Automatic sample preparation of35S labelled organic compounds for liquid scintillation counting

An automatic sample preparation method for the determination of³⁵S in organic compounds by liquid scintillation counting is described. The sample is burned in a stream of oxygen and the combustion products are led onto a quartz wool column wetted with dilute hydrogen peroxide. Sulfur oxides are retained on the quartz wool as sulfuric acid, while the other acid producing combustion products are eliminated by evaporation. The residual sulfuric acid in rinsed with distilled water, the sulfuric acid solution obtained is added to a liquid scintillation cocktail and the radioactivity is measured with a liquid scintillation counter. The combustion-evaporation process runs automatically according to the operational program carried out by an electronic programmer.     

Identifying Chemical Composition,Safety and Bioactivity of Thai Rice Grass Extract Drink in Cells and Animals

Rice grass has been reported to contain bioactive compounds that possess antioxidant and free-radical scavenging activities. We aimed to assess rice grass extract (RGE) drink by determining catechin content, free-radical scavenging and iron-binding properties, as well as toxicity in cells and animals. Young rice grass (Sukhothai-1 strain) was dried, extracted with hot water and lyophilized in a vacuum chamber. The resulting extract was reconstituted with deionized water (260 mg/40 mL) and served as Sukhothai-1 rice grass extract drink (ST1-RGE). HPLC results revealed at least eight phenolic compounds, for which the major catechins were catechin, epicatechin and epigallocatechin-3-gallate (EGCG) (2.71–3.57, 0.98–1.85 and 25.47–27.55 mg/40 mL serving, respectively). Elements (As, Cu, Pb, Sn and Zn) and aflatoxin (B1, B2, G1 and G2) contents did not exceed the relevant limits when compared with WHO guideline values. Importantly, ST1-RGE drink exerted radical-scavenging, iron-chelating and anti-lipid peroxidation properties in aqueous and biological environments in a concentration-dependent manner. The drink was not toxic to cells and animals. Thus, Sukhothai-1 rice grass product is an edible drink that is rich in catechins, particularly EGCG, and exhibited antioxidant, free radical scavenging and iron-binding/chelating properties. The product represents a functional drink that is capable of alleviating conditions of oxidative stress and iron overload.     

Simultaneous liquid scintillation determination of239Pu and241Am in tissue

A liquid scintillation counting method for the simultaneous determination of Pu and Am, with a two-phase cocktail, has been applied to the analysis of a tissue sample from an accidental exposure incident. The sample contained²³⁹Pu,²⁴¹Pu, and²⁴¹Am. In addition to analysis by two liquid scintillation counting techniques, analysis of the sample was performed by -spectroscopy and ZnS scintillation techniques, and the results were compared. The presence of²⁴¹Pu interfered with the liquid scintillation determination of²⁴¹Am when the two-phase cocktail was used, but the results were in agreement sufficient to be useful in determining what course of treatment, if any, might be necessary for the patient.     

GasBench/isotope ratio mass spectrometry: a carbon isotope approach to detect exogenous CO(2) in sparkling drinks

A new procedure for the determination of carbon dioxide (CO(2)) (13)C/(12)C isotope ratios, using direct injection into a GasBench/isotope ratio mass spectrometry (GasBench/IRMS) system, has been developed to improve isotopic methods devoted to the study of the authenticity of sparkling drinks. Thirty-nine commercial sparkling drink samples from various origins were analyzed. Values of delta(13)C(cava) ranged from -20.30 per thousand to -23.63 per thousand, when C3 sugar addition was performed for a second alcoholic fermentation. Values of delta(13)C(water) ranged from -5.59 per thousand to -6.87 per thousand in the case of naturally carbonated water or water fortified with gas from the spring, and delta(13)C(water) ranged from -29.36 per thousand to -42.09 per thousand when industrial CO(2) was added. It has been demonstrated that the addition of C4 sugar to semi-sparkling wine (aguja) and industrial CO(2) addition to sparkling wine (cava) or water can be detected. The new procedure has advantages over existing methods in terms of analysis time and sample treatment. In addition, it is the first isotopic method developed that allows (13)C/(12)C determination directly from a liquid sample without previous CO(2) extraction. No significant isotopic fractionation was observed nor any influence by secondary compounds present in the liquid phase.     

Quantitative analysis of triphenylboron in environmental water samples by liquid chromatography/mass spectrometry.

Liquid chromatography/mass spectrometry (LC/MS) has been applied to the analysis of triphenylboron, which has been produced as a substitute for organotin compounds, in water. Although commercial triphenylboron compounds are produced as pyridinyl complexes, the chemical form in water is supposed to be mainly triphenylboron after liberating pyridine. The triphenylborons were extracted from water with an Empore C18 extraction disk under acidic condition, and the extracts were introduced directly into a liquid chromatograph-mass spectrometer equipped with a negative ion electrospray ionization interface. Identification of the compounds was performed with specific ions produced from the triphenylboron, and a quantitative analysis was carried out using the peak areas. The average recoveries from distilled water, seawater and river water at 0.30 ng/ml were 92.3, 100 and 85.3%, respectively. A detection limit of 0.023 ng/ml for triphenylboron was achieved.     

Radium isotopes and <Superscript>222</Superscript>Rn in Austrian drinking waters

The activity concentrations of the Ra isotopes, ²²⁶Ra and ²²⁸Ra, as well as of ²²²Rn were measured in Austrian tap waters. Rn was extracted into a mineral oil cocktail not miscible with water and measured by liquid scintillation counting using pulse-shape analysis for α/β-separation. Ra isotopes were co-precipitated with BaSO₄ or concentrated by filtration through an element specific filter. EDTA solution was used to redissolve the precipitate as well as to release the Ra from the filter. After mixing with a cocktail, the EDTA solution was measured by liquid scintillation counting, too. From our results the effective ingestion doses for adults and 3 months old babies were calculated.     

Automated sample treatment with the injection of large sample volumes for the determination of contaminants and metabolites in urine

This work reports the development of a simple and automated method for the quantitative determination of several contaminants (triazine, phenylurea, and phenoxyacid herbicides; carbamate insecticides and industrial chemicals) and their metabolites in human urine with a simplified sample treatment. The method is based on the online coupling of an extraction column with RP LC separation–UV detection; this coupling enabled fast online cleanup of the urine samples, efficiently eliminating matrix components and providing appropriate selectivity for the determination of such compounds. The variables affecting the automated method were optimized: sorbent type, washing solvent and time, and the sample volume injected. The optimized sample treatment reported here allowed the direct injection of large volumes of urine (1500 μL) into the online system as a way to improve the sensitivity of the method; limits of detection in the 1–10 ng/mL range were achieved for an injected volume of 1500 μL of urine, precision being 10% or better at a concentration level of 20 ng/mL. The online configuration proposed has advantages such as automation (all the steps involved in the analysis – injection of the urine, sample cleanup, analyte enrichment, separation and detection – are carried out automatically) with high precision and sensitivity, reducing manual sample manipulation to freezing and sample filtration.     

Fruits Vinegar: Quality Characteristics,Phytochemistry, and Functionality

The popularity of fruits vinegar (FsV) has been increased recently as a healthy drink wealthy in bioactive compounds that provide several beneficial properties. This review was designed in the frame of valorization of fruits vinegar as a by-product with high value added by providing overall information on its biochemical constituents and beneficial potencies. It contains a cocktail of bioactive ingredients including polyphenolic acids, organic acids, tetramethylperazine, and melanoidins. Acetic acid is the most abundant organic acid and chlorogenic acid is the major phenol in apple vinegar. The administration of fruits vinegar could prevent diabetes, hypercholesterolemia, oxidative stress, cancer, and boost immunity as well as provide a remarkable antioxidant ability. The production techniques influence the quality of vinegar, and consequently, its health benefits.     

Quantitative measurement of male steroid hormones using automated on-line solid phase extraction-liquid chromatography-tandem mass spectrometry and comparison with radioimmunoassay

A specific and sensitive method using high-performance liquid chromatography-tandem mass spectrometry (LC-MS-MS) equipped with automatic on-line solid-phase extraction device for the quantitative measurement of anabolic hormone residues, 4-androstene-3,17-dione, testosterone and dihydrotestosterone in cell culture medium was developed. Steroid content in cell culture medium was determined directly without an additional sample preparation step. Separation of analytes from polar endogenous compounds was carried out on an automatic column-switching device coupled with a C4-alkyl-diol silica restricted-access solid-phase extraction column. The lipophilic fraction containing anabolic hormone residues were back-flushed on to a conventional C-18 reversed-phase column for the final chromatography. The analyte was ionized in an ElectroSpray interface under positive ion mode before entering a quadrupole mass analyzer. The lowest points of calibration curves were 0.05 ng ml(-1) for 4-androstene-3,17-dione and testosterone, and 1 ng ml(-1) dihydrotestosterone, respectively. A comparison with results from radioimmunoassay (RIA) is also presented.     

Determination of the herbicide 4-chloro-2-methylphenoxyacetic acid and its main metabolite, 4-chloro-2-methylphenol in water and soil by liquid chromatography-electrospray tandem mass spectrometry

A rapid and sensitive LC-electrospray tandem mass spectrometry method has been developed for the quantitation of 4-chloro-2-methylphenoxyacetic acid (MCPA) and 4-chloro-2-methylphenol in both water and soil samples. Soil samples were extracted in alkaline media and cleaned-up by solid-phase extraction with C18 cartridges before LC-MS analysis. The selectivity and sensitivity offered by the triple quadrupole allowed the direct injection of the water samples rendering a sample throughput of around 100 samples per day, without any sample pretreatment, rendering for MCPA a limit of detection of 40 ng/l. In order to increase the method sensitivity, mainly for metabolite, a previous solid-phase extraction step was also performed. The method was validated by means of recovery experiments using fortified water and soil samples, obtaining satisfactory recoveries for both compounds in water and for MCPA in soil. The validated procedures can be used for the specific monitoring of residues of MCPA and its main metabolite in environmental samples, as ground and surface waters and soils, providing more selectivity and sensitivity than the current UV-based methodology. Besides, sample manipulation is greatly reduced in comparison to other GC-MS based methods which require a previous derivatization.     

Application of ultrasound-assisted extraction to the determination of contaminants in food and soil samples

The application of ultrasound-assisted extraction (UAE) to the sample preparation of environmental and food samples has increased in the last years. This technique has been used in the development of methods for the analysis of numerous contaminants, including organic compounds (pesticides, pharmaceuticals, polycyclic aromatic hydrocarbons, polyhalogenated flame retardants, etc.) and heavy metals. The aim of this work is to review the application of this extraction procedure to the analysis of contaminants in food and soil and the comparison of its use with other well-established extraction procedures. The advantages and disadvantages of this technique together with the possibility of coupling UAE with other analytical techniques will be also discussed.     

液相色谱-串联质谱法快速测定饮用水中6种雌激素

建立了液相色谱-质谱法测定饮用水中17-β-雌二醇、17-α-雌二醇、17-α-乙炔雌二醇、己烷雌酚(HEX)、己烯雌酚(DES)和双烯雌酚(DE)6种雌激素的分析方法.样品经乙腈萃取,Oasis HLB柱富集净化后,采用液相色谱-质谱法测定.方法在5～100 μg/L范围内呈良好线性,相关系数为0.994～1.000...     

Removal of the impurities from environmental water samples for tritium measurement by liquid scintillation counting

Liquid scintillation counting is the most popular method for tritium measurement, however, it takes much time and a lot of doing to distill off the impurities before mixing the sample water and liquid scintillation cocktail. We have investigated the possibility of an alternative method to the distillation. We have found out that the filtration can be an alternative to distillation for the environmental water samples before electrolytic enrichment.     

Phenotyping of CYP450 in human liver microsomes using the cocktail approach

The cocktail approach is an advantageous strategy used to monitor the activities of several cytochromes P450 (CYPs) in a single test to increase the throughput of in vitro phenotyping studies. In this study, a cocktail mixture was developed with eight CYP-specific probe substrates to simultaneously evaluate the activity of the most important CYPs, namely, CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and the CYP3A subfamily. After cocktail incubation in the presence of human liver microsomes (HLMs), the eight selected substrates and their specific metabolites were analyzed by ultra-high-pressure liquid chromatography and electrospray ionization quadrupole time-of-flight mass spectrometry. Qualitative and quantitative data were simultaneously acquired to produce an overview of the extended phase I biotransformation routes for each probe substrate in the HLMs and to generate phenotypic profiles of various HLMs. A comparison of the cocktail strategy with an individual substrate assay for each CYP produced similar results. Moreover, the cocktail was tested on HLMs with different allelic variants and/or in the presence of selective inhibitors. The results were in agreement with the genetic polymorphisms of the CYPs and the expected effect of the alterations. All of these experiments confirmed the reliability of this cocktail assay for phenotyping of the microsomal CYPs.     

Exploratory analysis and inductively coupled plasma optical emission spectrometry (ICP OES) applied in the determination of metals in soft drinks

A 2³ factorial design and a CCD (Central Composite Design) were employed to optimize the operational conditions for determining Al, Ba, Ca, Cd, Cr, Cu, K, Mg, Na, Ni, Pb, Sn and Zn in soft drink samples by inductively coupled plasma optical emission spectrometry (ICP OES). Satisfactory parameters of merit were obtained (Plasma stability, linearity, SBR, BEC, LOD and LOQ). The accuracy was evaluated by means of a recovery study. Thirty five soft drink samples were analyzed. The results obtained were used in an exploratory analysis, in which principal component analysis and cluster analysis were applied in order to differentiate the several soft drink classes. Adequate LOQ values were obtained for all elements (0.34 μg L^− 1 for Ca to 88.7 μg L^− 1 for Mg) and the recovery study results ranged between 80 and 100%. Cluster analysis revealed four sample classes characterized by flavor and other characteristics, such as being light, diet, low calorie or regular beverages. A model with 4 PCs was obtained by means of a principal component analysis, which explained 99.8% of the total variance.     

高效液相色谱-四极杆飞行时间质谱法同时检测豆芽中的3种外源植物激素残留

建立了高效液相色谱-四极杆飞行时间质谱同时测定豆芽中6-苄基腺嘌呤、4-氯苯氧乙酸、赤霉素等3种外源植物激素残留的方法。采用QuEChERS前处理技术,豆芽样品以酸化乙醇-乙腈溶液（1%（v/v,下同）乙酸+50%乙醇+49%乙腈）提取目标化合物,并经乙腈再提取后合并提取液;经硅藻土分散固相净化、正己烷去脂后氮吹至近干;用2.0 mL 50%（v/v）甲醇水溶液定容,过滤膜后上机检测。液相色谱以甲醇-水（含0.1%（v/v）的甲酸）作为流动相梯度洗脱,C₁₈色谱柱分离;质谱采用高分辨质谱、负离子模式,以精确质量数和二级特征离子定性,以准分子离子峰面积定量。结果表明3种目标化合物的定量限为5.0~10.0 μg/kg,线性范围为1~200 μg/L;平均添加回收率为79.1%~96.1%,相对标准偏差为5.7%~10.4%。本方法具有操作简单、快捷、灵敏度高等优点,适用于市场上豆芽质量的快速筛查检测。