LC-QTOF-MS as a superior strategy to immunoassay for the comprehensive analysis of synthetic cannabinoids in urine

The objective of this study was to compare the performance of an immunoassay screening for synthetic cannabinoids with a newly developed confirmation method using liquid chromatography quadrupole time-of-flight mass spectrometry. The screening included metabolites from JWH-018, JWH-073, and AM-2201. The confirmation included metabolites from AM-2201, JWH-018, JWH-019, JWH-073, JWH-081, JWH-122, JWH-210, JWH-250, JWH-398, MAM-2201, RCS-4, and UR-144. The immunoassay was tested and found to have no cross-reactivity with UR-144 metabolites but considerable cross-reactivity with MAM-2201 and JWH-122 metabolites. Sensitivity and specificity for the immunoassay were evaluated with 87 authentic urine samples and found to be 87 % and 82 %, respectively. With a cutoff at 2 ng/ml, the confirmation showed 80 positive findings in 38 cases. The most common finding was JWH-122 5-OH-pentyl, followed by JWH-018 5-OH-pentyl. There were 9 findings of UR-144 metabolites and 3 of JWH-073 metabolites. In summary, the immunoassay performed well, presenting both high sensitivity and specificity for the synthetic cannabinoids present in the urine samples tested. The rapid exchange of one cannabinoid for another may pose problems for immunoassays as well as for confirmation methods. However, we consider time-of-flight mass spectrometry to be superior since new metabolites can be quickly included and identified.

Chromatographic separation and identification of human urine components

Summary Ultraviolet-absorbing components of human urine were separated by HPLC with a large scale column (250 × 28 mm I.D. stainless-steel) containing a macroreticular type strongly basic anion-exchange resin. The sample was eluted with a linear gradient of 0.006 M to 6.0 M ammonium acetate buffer (pH 4.40) and different fractions were collected. The identification of one compound using ultraviolet, infrared and mass spectral data is illustrated; it was found to be uric acid.     

A new method for the isolation and estimation of Furan-2,5-dicarboxylic acid in human urine

Summary A new, concise and efficient method of isolation and estimation of F. D. A. avoiding heating with acids, has been devised.Inositol and calcium gluconate when added to urine and subjected to the old method of isolation of F. D. A. result in no increase in the amount of F. D. A. This indicates that the increase in the output of this acid obtained before⁴ was a process within the body itself.Metabolic experiments with inositol and calcium gluconate adopting the new method gave a 3–4 fold increase in the F. D. A. output confirming that this increase is anin vivo process.

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Zusammenfassung Eine neue, genaue Methode zur Isolierung und Bestimmung von Furandicarbonsäure (F. D. C.) ohne Erhitzen des angesäuerten Untersuchungs-materials wurde ausgearbeitet. Werden Inosit und Calciumgluconat dem Harn vor Aufarbeitung nach der alten Methode zugesetzt, so führt dies zu keiner Erhöhung der F. D. C.-Menge. Die früher beobachtete Vermehrung der F. D. C.-Menge ist also die Folge von Vorgängen innerhalb des Organismus. Stoffwechselexperimente mit Inosit und Calciumgluconat mit der neuen Methode zeigen eine drei bis vierfach gesteigerte F. D. C.-Ausscheidung und bestätigen damit deren vermehrte Bildung in vivo.

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Résumé On a imaginé une nouvelle méthode rapide et efficace pour isoler et doser le F. D. A. en évitant le chauffage avec les acides. L'inositol et le gluconate de calcium, ajoutés à l'urine et soumis à la vieille méthode d'isolement du F. D. A. ne produisent pas de surcharge sur la quantité de F. D. A. Ce fait indique que l'augmentation du rendement de cet acide, obtenue auparavant, était un processus dans le corps humain lui-même.Des expériences sur le métabolisme avec l'inositol et le gluconate de calcium, en adoptant la nouvelle méthode, ont donné une augmentation de trois à quatre fois le rendement en F. D. A., ce qui confirme que cette augmentation se produitin vivo.

     

Amperometric biosensor for oxalate determination in urine using sequential injection analysis

An amperometric flow biosensor for oxalate determination in urine samples after enzymatic reaction with oxalate oxidase immobilized on a modified magnetic solid is described. The solid was magnetically retained on the electrode surface of an electrode modified with Fe (III)-tris-(2-thiopyridone) borate placed into a sequential injection system preceding the amperometric detector. The variables involved in the system such as flow rate, aspired volumes (modified magnetic suspension and sample) and reaction coil length were evaluated using a Taguchi parameter design. Under optimal conditions, the calibration curve of oxalate was linear between 3.0-50.0 mg·L^-1, with a limit of detection of 1.0 mg·L^-1. The repeatability for a 30.0 mg·L^-1 oxalate solution was 0.7%. The method was validated by comparing the obtained results to those provided by the spectrophotometric method; no significant differences were observed.     

Determination of phosphate in urine by sequential injection analysis

Two simple turbidimetric methods for the determination of phosphate in urine are presented and compared. One method is based on the calcium phosphate crystallisation, and the other one on the inhibitory action of phosphate on the calcium carbonate crystallisation. The analytical features of both methods were: linear range = 0.2-1.5 g L-1, LOD = 14 mg L-1 and RSD 1.1-2.0% for the calcium phosphate method, linear range = 0.1-1.8 mg L-1, LOD = 0.01 mg L-1 and RSD 0.97-1.90% for the inhibitory method. Urines with high calcium content (> or = 400 mg L-1) can interfere the method based on the crystallisation of calcium phosphate. This interference was solved using a cation exchange resin as a part of the manifold. Considering the low toxicity of used reagents, these methods can be considered as a contribution to Green Analytical Chemistry.     

A new strategy for exploiting ion exchange in sequential injection analysis: in-line phytic acid separation/determination in foods as an example.

A novel strategy for exploiting ion exchange in sequential injection systems is proposed. The procedure is based on the selection of a defined volume of a resin suspension, which is introduced and packed in the analytical path, establishing a resin mini-column in the system. The passage of a selected sample volume through the resin mini-column leads to the retention of the analyte, while the sample matrix is discarded. The analyte is eluted during the passage of the eluant/reagent by the packed beads, being the analytical signal monitored (absorbance) in the liquid phase. The beads are then aspirated back to the holding coil and directed to a recovery flask, linked at the selection valve; then the system is ready to begin a new cycle. With the proposed strategy, the main characteristics of the sequential injection system are kept as any new artifact is added to the manifold and system reconfiguration is not required. The feasibility of the approach is demonstrated by the phytic acid determination in food samples. For this specific application, AG1-X8 was selected as ion exchanger, and a solution containing Cl- and Fe(III)-salicylate complex was used as eluant and spectrophotometric reagent.     

A flow sampling strategy for the analysis of oil samples without pre-treatment in a sequential injection analysis system

The present work describes a sequential injection analysis (SIA) system adapted to direct analysis of oil samples. In this way, the flow system was designed by incorporation, in the SIA system, of an injection valve that was responsible for the sample insertion. With the developed sampling strategy the sample pre-treatment outside the flow system is avoided and also the problems associated with viscous samples in flow systems.The developed SIA system was applied to the determination of iron (Fe(III)) in edible oil samples and was based on the formation of a red complex (λ = 510 nm) between Fe(III) and thiocyanate in organic medium. A mixture of methanol:chloroform (85:15) was used as carrier solution and possible refractive index associated with the spectrophotometric detection was avoided by introduction of a mixing chamber in the flow system. The presented methodology produced 4.2 ml of effluent and consumed 150 μl of sample and 0.95 mg of thiocyanate per determination.Linear calibration plots were obtained for Fe(III) concentrations up to 25 mg l⁻¹ and the detection limit of the determination was 0.31 mg l⁻¹. The developed methodology exhibited a good precision, with an R.S.D. < 3.5% (n = 15) and a determination frequency of 20 determinations h⁻¹. The results of the analysis were evaluated by recovery studies (96.5-104.5%) and by the analysis of two AOCS reference samples.     

A general strategy for the facile synthesis of 2,7-dibromo-9-heterofluorenes

[reaction: see text] A facile, highly efficient, and economical procedure for the preparation of 6,6'-diiodo-4,4'-dibromo-3,3'-dimethoxylbiphenyl has been found. From this compound, a general synthetic strategy for the preparation of 2,7-dibromo-9-heterofluorenes has been developed. Five 2,7-dibromo-9-heterofluorenes have been easily synthesized for the first time according to the procedure presented, opening the door to new classes of inorganic and organometallic conjugated polymeric materials of polyheterofluorenes.     

A sequential multielement separation scheme for determination of As,Mn, Mo,Cu and Zn in human milk by neutron activation analysis

A simple separation scheme for the analysis of As, Mn, Mo, Cu and Zn using neutron activation is described. It has been checked using three standard reference materials, A-11 milk powder (IAEA) and bovine liver and orchard leaves (USNBS) and found to give acceptable results. This scheme was applied for determination of these trace elements in mature human milk samples. The concentrations of As, Mn, Mo, Cu in samples obtained from two socio-economic groups—low and middle incomes—were not significantly different. However, Zn levels in samples obtained from the poor income group were significantly lower than in those obtained from the other group. Work carried out under Research Contract No. 2598/RB of International Atomic Energy, Vienna. Health Physics Division. Analytical Chemistry Division.     

Novel tandem column method for the rapid isolation of radiostrontium from human urine

A method has been developed for the isolation of strontium from human urine for subsequent determination in sample volumes as low as 5–20 mL. This method involves the acidification of the sample using methanesulfonic acid and its decolorization using charcoal, treatment of the filtrate with Diphonix^® resin, and subsequent concentration of strontium on Sr resin. Data from retention model simulations provided the initial conditions which were then optimized by actual column separations. Diphonix^® resin was shown to be effective at removing alkali metal ions from the urine matrix under conditions that retain higher valence ions. The suggested processing method provides 99% recovery of Sr²⁺, a concentration factor of 50, and an expected per sample processing time of less than 1 h.     

A facile strategy to prevent trifluoroacetylation of N-terminal proline peptides

Unwanted trifluoroacetylation occurred at the N-terminus of prolinyl peptides during detachment from the solid phase. This was observed when the N-α-Fmoc protecting group had been removed prior to the final TFA treatment. Subtly changing the SPPS protocol and incorporating Boc- in place of the Fmoc-protected proline as the N-terminal building block efficiently suppressed this side reaction.     

A facile synthetic strategy for hyperbranched polymer via combining free radical telomerization and polycondensation

A facile strategy combining free radical telomerization and polycondensation to prepare hyperbranched polymers was developed. By selecting a suitable telogen and a vinyl monomer, the product obtained by telomerization could be regarded as an AB_n type monomer for preparing a hyperbranched polymer via conventional polycondensation. The principles for selecting vinyl monomers and telogens were proposed. The feed ratio of vinyl monomer to telogen was discussed in the theory. For demonstrating the strategy, methyl (meth)acrylate (MA or MMA) and 2‐mercaptoethanol were used as a vinyl monomer and a telogen, respectively. The two‐unit adduct of MA or MMA obtained after purifying was regarded as a model ABB′ monomer. The sequential transesterification demonstrated that the carboxylate group at the terminal unit has higher reactivity than that at penultimate unit because of the different substituents at the respective α‐positions, resulting in lower degree of branching (DB) of obtained polymer. As substitutes, 2‐hydroxyethyl (meth)acrylate and thioglycolic acid were used as a vinyl monomer and a telogen, respectively. The results showed that the hyperbranched polymer obtained by using pseudo one‐pot approach had moderate DB. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7543–7555, 2008     

A simple and low-energy strategy for the separation of water and acetonitrile

As acetonitrile is a widely used solvent for the chemical industry, the recovery of acetonitrile from acetonitrile wastewater is significant for both industrial cost reduction and environmental protection. In this article, a simple, low-energy, and low-cost strategy is proposed for the effective separation of acetonitrile from high-concentration acetonitrile wastewater. The approach is based on a sequential combination of two steps: salt-induced phase separation and hydrophobic filtration. The acetonitrile wastewater was first induced to split into two phases by salt, that is, the acetonitrile-rich phase and the water-rich phase, then the above two phases were poured into the hydrophobic filter paper funnel for the separation. It was shown that NaCl is a suitable salting-out reagent, and that hydrophobic filter papers—obtained from modification by butyltrichlorosilane and octyltrichlorosilane were the optimal choice for hydrophobic filtration. The salt-induced phase separation process is able to increase the volume fraction of acetonitrile in the acetonitrile-rich phase up to 92%. The acetonitrile-rich phase can pass through the hydrophobic filter paper, whereas the water-rich phase was intercepted. The hydrophobic filter paper retained strong hydrophobicity and high acetonitrile-separating capacity after 3 months storage, or upon immersion in acetonitrile-water mixtures for 12 h, or applied for 25 consecutive separations.     

无溶剂路线制备分子筛封装的钴基催化剂及其在费托合成制汽油反应中的应用（英文）

自2012年浙江大学肖丰收教授(J.Am.Chem.Soc.,2012,134,15173-15176)首次提出无溶剂法合成分子筛以来,该路线已备受关注.无溶剂合成分子筛方法具有废液少、产率高、安全系数高等优点.本文针对合成气经费托路线(FTS)一步法制备富含异构烷烃汽油馏分的研究,通过无溶剂研磨法制备了分子筛封装金属催化剂.一般来说,烷烃异构化催化剂的性能主要取决于分子筛的孔道结构及其酸性,其次是分子筛晶粒大小、结晶度和表面性质等因素.本文对比了三种具有相同拓扑结构的MFI分子筛(Silicalite-1,HZSM-5和NaZSM-5)对汽油和异构烷烃选择性的影响规律.结果显示,在CO转化率(～30%)近似相同的情况下,具有最弱酸性的Silicalite-1封装的Co颗粒表现出最高的汽油选择性(～70%)和异构烷烃选择性(～30.7%).这意味着正构烷烃异构化反应只需要弱酸即可实现,较强的酸性则会使其发生过度裂解反应.Py-IR谱图显示,Silicalite-1在1445 cm^-1附近的L酸是区别于NaZSM-5和HZSM-5的一个重要酸性位,可作为FTS路线制...     

Sensitive determination of indomethacin in pharmaceuticals and urine by sequential injection analysis and optosensing

A selective and sensitive method based on coupling of sequential injection analysis (SIA) and optosensing was developed and applied to the determination of indomethacin in pharmaceutical and urinary samples. After alkaline hydrolysis, the fluorescent product generated from indomethacin is inserted in the flow system, transitorily retained on an active solid support (Sephadex QAE A-25) filling the flowcell, and monitored at 283/371 nm (lamda ex / lamda em). The system was calibrated for two sample volumes, 100 and 1000 microL. It showed a linear dynamic range of 0.5-6.5 ng/mL, with an LOD of 0.15 ng/mL and an RSD of 3.9% (n=10) when the highest sample volume was used. The proposed fluorometric SIA optosensor was applied to the determination of indomethacin in both pharmaceuticals and urine samples, and satisfactory results were obtained.     

A facile and efficient strategy for one-step in situ preparation of hydrophobic organic monolithic stationary phases by click chemistry and its application on protein separation

A simple one-step in situ “click” modification strategy was developed for the preparation of hydrophobic organic monolithic columns for the first time. The column morphology and surface chemistry of the fabricated monolithic columns were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, respectively. The chromatographic performances of the C8/C18 “click” monoliths were evaluated through the separation of a mixture of five proteins such as ribonuclease A, soybean trypsin inhibitor, cytochrome c, bovine haemoglobin and bovine serum albumin. Compared with the blank column, the higher hydrophobicity stationary phases obtained from the “clicked” modification have longer retention times and higher resolution for the five proteins. The separation of five proteins mixture on click C18 monolith with gradient elution at different flow rates was also investigated, the baseline separation of five proteins could be achieved at three different flow rates.     

A strategy for high-throughput analysis of levosimendan and its metabolites in human plasma samples using sequential negative and positive ionization liquid chromatography/tandem mass spectrometric detection

Levosimendan (Simdax) is an approved drug in approximately 40 countries and currently in phase III clinical studies in the USA and Europe. An accurate, high-throughput and rugged assay is critical to support these clinical trials. Due to the mechanism of drug metabolism, the drug and its active metabolites often have significant differences in their chemical properties. In order to achieve high assay throughput and low sample volumes, a single bioanalytical assay for the drug and its metabolites is preferred. However, this need may prevent the optimization of both high-performance liquid chromatography (HPLC) and mass spectrometric ionization conditions. The chemical properties of levosimendan are significantly different from those of its two active metabolites, OR-1855 and OR-1896. Here, we present a novel strategy for high-throughput analysis of levosimendan and its metabolites. A 96-well liquid/liquid extraction procedure was developed for sample preparation. A single liquid chromatography/tandem mass spectrometry (LC/MS/MS) system with two separate mobile phases, shared backwash solvent and conditioning solvent, was developed to perform sequential LC separation for levosimendan and the metabolites. Levosimendan was eluted by 5 mM ammonium acetate in 33.3% acetonitrile and detected using negative ionization mode MS/MS monitoring. The metabolites were eluted by 5 mM ammonium acetate and 0.2% acetic acid in 20% acetonitrile and detected with positive ionization mode MS/MS monitoring. The method has been demonstrated to have excellent precision and accuracy, with high assay ruggedness during method validation and clinical sample analysis. The linear dynamic ranges were approximately 200-50,000 pg/mL for levosimendan and approximately 500-130,000 pg/mL for both metabolites. The coefficient of determination (r2) for all analytes was greater than 0.9985. The intra-assay %CVs for QC samples were from 0.9% to 2.0% for levosimendan, 0.9% to 3.2% for OR-1855, and 0.4% to 4.9% for OR-1896. The inter-assay %CVs for QC samples were from 1.2% to 1.8% for levosimendan, 1.3% to 2.7% for OR-1855, and 1.4% to 3.4% for OR-1896. The mean % biases for QC samples were from 1.5% to 5.5% for levosimendan, -1.4% to 2.6% for OR-1855, and -0.3% to 4.5% for OR-1896. By using a single extraction approach coupled with sequential LC/MS/MS analysis for levosimendan and its metabolites, the assay maintained high throughput and low sample volume usage.     

A facile strategy to fabricate intumescent fire-retardant and smoke suppression protective coatings for natural rubber

As flammable natural rubber (NR) becomes more ubiquitous in industrial fields, there is a growing need for safe and effective flame retardant treatments through efficient techniques. Remarkably, our developed highly efficient natural tannic acid (TA)-based intumescent flame-retardant system (AGT) has the unique function in the rubber flame retardant aspect. Meanwhile, the developed coating method through polyurethane elastomer (PU) both as adhesive medium and a carbonforming agent can not only minimize the influence of flame retardant on the desirable intrinsic properties of base polymer and also maximize the efficiency of flame retardant. The flame-retardant coating (AGT/PU) exhibits highly efficient flame retardant performances reflected by a 31.9% reduction in peak heat release rate and a 27.3% reduction in total heat release and a 26.2% reduction in total smoke production with 50 wt% loading in 1 mm thick coating due to synergistic flame retardant effects. More importantly, the excellent flame retardancy performance are obtained by the PU@AGT10, as reflected in flame retardancy index (FRI) value of 11.88 makes it as excellent flame retardancy performance. While many physically mixed flame retardants are usually seriously detrimental to mechanical properties of NR, the influence of AGT/PU coating on mechanical properties of NR decreases obviously because fire retardant just directly impacts on PU adhesive layer rather than NR matrix, and the reinforcement function of graphene is also much significant. Moreover, the coating method requires just less flame retardant to achieve high flame retardant effect for NR. These findings suggest that significant opportunities for flame retardant polymer materials in industry.