Analytical phosphorus fractionation in sewage sludge and sediment samples

The Standards, Measurements and Testing (SMT) harmonized procedure for phosphorus fractionation in freshwater sediments (SMT protocol), which was developed within the framework of the Standards, Measurements and Testing (SMT) Programme of the European Commission, has been applied to different environmental samples such as sewage sludge, river and marine sediments. The phosphorus contents in the extracts were spectrophotometrically determined; the measurement conditions and the matrix effects were evaluated for each fraction. The partitioning patterns obtained for sewage sludge and sediment samples reveal that the distribution between inorganic and organic phosphorus forms is independent of the matrix composition of the samples. In addition, a higher available phosphorus content was found in sewage sludges due to the higher percentages of labile phosphorus forms, which suggests possible internal phosphorus release. Finally, one simplified pseudototal microwave digestion method was performed for total phosphorus determination which was validated by its application to the reference material BCR-684.     

Harmonized protocol and certified reference material for the determination of extractable contents of phosphorus in freshwater sediments--a synthesis of recent works.

An analytical protocol for the determination of the extractable phosphorus contents in freshwater sediments has been harmonized through interlaboratory studies in the frame of the Standards Measurements and Testing Program of the European Commission. A homogeneous and stable sediment reference material has been prepared and certified on the basis of this protocol named SMT protocol, and will be available in spring of 2001. The SMT protocol, together with the reference material, are useful tools in the field of water management, especially at a time when quality assurance and data comparability are of paramount importance in laboratory analysis. The knowledge of the bioavailable forms of phosphorus is important not only for sediments but also for sludge and soils. Therefore, the SMT protocol could be extended to these materials and new CRMs could be prepared. The SMT protocol was used in a study of a reservoir, which allowed to calculate the P stock, therefore helping to predict the restoration delay of the lake. The paper describes the protocol and the CRM, and gives a brief outline of the case study.     

Harmonized protocol and certified reference material for the determination of extractable contents of phosphorus in freshwater sediments – A synthesis of recent works

An analytical protocol for the determination of the extractable phosphorus contents in freshwater sediments has been harmonized through interlaboratory studies in the frame of the Standards Measurements and Testing Program of the European Commission. A homogeneous and stable sediment reference material has been prepared and certified on the basis of this protocol named SMT protocol, and will be available in spring of 2001. The SMT protocol, together with the reference material, are useful tools in the field of water management, especially at a time when quality assurance and data comparability are of paramount importance in laboratory analysis. The knowledge of the bioavailable forms of phosphorus is important not only for sediments but also for sludge and soils. Therefore, the SMT protocol could be extended to these materials and new CRMs could be prepared. The SMT protocol was used in a study of a reservoir, which allowed to calculate the P stock, therefore helping to predict the restoration delay of the lake. The paper describes the protocol and the CRM, and gives a brief outline of the case study. Received: 14 November 2000 / Revised: 25 January 2001 / Accepted: 31 January 2001     

Determination of phosphorus in hypereutectic aluminium-silicon alloys

A reproducible method is described for determination of small amounts of phosphorus (from 0.0005% to 0.02%) in hypereutectic aluminium-silicon complex alloys. The method permits the separate determination of phosphorus in acid-soluble and acid-insoluble fractions. Phosphomolybdate is extracted with n-butanol-chloroform solvent mixture and back-extracted with a btannous chloride reducing solution. The phosphorus content of a sample cut into small pieces decreases during storage; loss of phosphorus is negligible on acid dissolution under oxidizing conditions.     

A multisyringe flow-through sequential extraction system for on-line monitoring of orthophosphate in soils and sediments

A fully automated flow-through microcolumn fractionation system with on-line post-extraction derivatization is proposed for monitoring of orthophosphate in solid samples of environmental relevance. The system integrates dynamic sequential extraction using 1.0 mol l⁻¹ NH₄Cl, 0.1 mol l⁻¹ NaOH and 0.5 mol l⁻¹ HCl as extractants according to the Hieltjes-Lijklema (HL) scheme for fractionation of phosphorus associated with different geological phases, and on-line processing of the extracts via the Molybdenum Blue (MB) reaction by exploiting multisyringe flow injection as the interface between the solid containing microcolumn and the flow-through detector. The proposed flow assembly, capitalizing on the features of the multicommutation concept, implies several advantages as compared to fractionation analysis in the batch mode in terms of saving of extractants and MB reagents, shortening of the operational times from days to hours, highly temporal resolution of the leaching process and the capability for immediate decision for stopping or proceeding with the ongoing extraction. Very importantly, accurate determination of the various orthophosphate pools is ensured by minimization of the hydrolysis of extracted organic phosphorus and condensed inorganic phosphates within the time frame of the assay. The potential of the novel system for accommodation of the harmonized protocol from the Standards, Measurement and Testing (SMT) Program of the Commission of the European Communities for inorganic phosphorus fractionation was also addressed. Under the optimized conditions, the lowest detectable concentration at the 3σ level was ≤0.02 mg P l⁻¹ for both the HL and SMT schemes regardless of the extracting media. The repeatability of the MB assay was better than 2.5% and the dynamic linear range extended up to 7.0 mg P l⁻¹ in NH₄Cl and NaOH media and 15 mg P l⁻¹ whenever HCl is utilized as extractant for both the HL and SMT protocols.     

Identification and determination of sulphamethazine and N4-acetylsulphamethazine in meat by high-performance liquid chromatography with photodiode-array detection

A simple and selective method for the determination of sulphamethazine (SMT) and its metabolite, N4-acetylsulphamethazine (N4-AcSMT), in meat by high-performance liquid chromatography (HPLC) with photodiode-array detection was developed. The drugs were extracted from meat with 0.2% metaphosphoric acid-methanol (6:4), followed by a Bond-Elut C18 clean-up procedure. The HPLC separation was carried out on a Supersphere RP-18e column (125 X 4.0 mm I.D.) using 0.05 M sodium dihydrogenphosphate (pH 4.5)-acetonitrile (8:2) as the mobile phase at a flow-rate of 0.5 ml/min, and monitored with a photodiode-array detector. The recoveries of SMT and N4-AcSMT from meat fortified at 0.5 micrograms/g were 90.1-93.3 and 93.0-94.4%, respectively, with coefficients of variation of 1.9-3.2 and 1.5-2.7%. The limits of detection were 0.02 micrograms/g for each drug. SMT was found in ten samples of imported meat (12.5%) at levels ranging from 0.05 to 1.05 micrograms/g.     

Comparison of digestion methods for determination of total phosphorus in river sediments

In this study, four digestion methods used to determine total phosphorus in river sediments, including Na₂CO₃ fusion, the H₂SO₄ and H₂SO₄ + H₂O₂ methods and the SMT protocol were investigated. Interference effects of iron, calcium and organic matter in river sediments, and the substances contained in the digestion agents on the photometric determination of the phosphates were analysed. The digestion methods were tested on ten river sediment samples. Statistical analysis of the results showed significant differences between sample treatments relating to the mean total phosphorus concentration.     

Bromatometric assay of simvastatin in pharmaceuticals

Titrimetric and spectrophotometric methods are proposed for the determination of simvastatin (SMT) in bulk drug and in tablets. The methods employ bromate-bromide mixture in acid medium as the brominating agent and iron (III) and thiocyanate as auxiliary regents. In titrimetry, SMT is treated with a measured excess of bromate-bromide mixture in HCl medium, and after a definite time, the unreacted bromine is determined iodometrically. In spectrophotometric method, the residual bromine is reduced by iron (II) and the resulting iron (III) is complexed with thiocyanate, and the absorbance is measured at 470 nm. In both methods, the amount of in situ generated bromine corresponds to the SMT content. The experimental conditions are optimized. Titrimetry is applicable over 1–10 mg range and the calculations are based on the molar ratio of 1: 0.666 (SMT: KBrO3). In spectrophotometric method, Beer’s law is obeyed over the concentration range 1–10 µg/mL. The calculated molar absorptivity is 3.02 × 10⁴ L/mol cm and the corresponding sandel sensitivity being 0.0081 µg/cm². The limit of detection (LOD) and limit of quantification (LOQ) are calculated to be 0.10 and 0.31 µg/mL, respectively. The intra-day and inter-day precision calculated from the analysis of pure SMT were less than 2 and 2.7%, respectively. The methods were satisfactorily applied to the determination of SMT in tablets, and no interferences from common tablet excipients were observed. The validity of the methods was further ascertained by parallel assay by an established technique and by recovery studies.     

Determination of Phosphorus in Chlorosilanes) And High Purity Silica By Atomic Absorption Spectrophotometer

Abstract

Determination of traces of impurities in chloro-silanes and high purity silica are important in the preparation of semiconductor grade silicon. The author have developed an indirect method for the determination of phosphorus in these materials. Phosphorus is extracted as phosphoantimonyl molybdate complex in methyl isobutyl ketone. The concentration of phorphorus is calculated by determining the concentration of antimony by atomic absorption spectrophotometer as antimony and phosphorus are present in 1:1 molar ratio in the complex. The method is selective and enables the determination of 0.1 ppm of phosphorus.     

ICP-MS测定屠宰场废水中总磷的方法研究

屠宰场废水中有机质含量高且颜色深,采用常规污水分析方法-消解分光光度法测定总磷较为繁琐.通过蒸干-灼烧法对样品进行前处理,使用电感耦合等离子体质谱(ICP-MS)方便快速地测定出屠宰场废水中总磷的含量.经实际样品验证,加标回收率为95.2%~102.0%.方法测定结果准确可靠,测定范围宽且效率高,对分析工作者具有一定的借鉴意义和参考价值.     

Analysis of some organochlorine pesticides in seafood samples by solid-phase extraction—Gas chromatography

Summary The use of the solid-phase extraction technique for the rapid sample preparation of organochlorine pesticides is described. Samples were simultaneously extracted, cleaned, and fractionated by the solid-phase extraction method and a further separation and determination of extracted fractions was carried out by gas chromatography with either an electron capture or a Hall electrolytic conductivity detector. The percent recovery of the extracted seven pesticides was compared to that of the conventional liquid-liquid extraction method. The analytical figures of merit., chromatograms, and statistic data are reported. The application of this method was demonstrated by a real fish sample determination with mass spectra for confirmation of Kepone detection.     

Determination of sulfamethazine in swine and cattle feed by reversed-phase liquid chromatography with post-column derivatization: collaborative study

A liquid chromatographic (LC) method for the analysis of sulfamethazine (SMT) in complete swine and cattle feed was collaboratively studied. The method uses post-column derivatization with dimethylaminobenzaldehyde and detection at 450 nm. To 5g finely ground feed, extractant (0.2N HCl + 1.5% diethylamine in 25% methanol), and internal standard solutions are added, and the SMT is extracted by shaking for 1 h. Clarified extract (high-level sample extract diluted to a target concentration of ca 5.5 microg/mL) is chromatographed on a Cla reversed-phase LC column with acetonitrile-2% acetic acid (17 + 83) mobile phase. Sulfamerazine is used as an internal, or surrogate standard to correct for variable recovery of sulfamethazine from a variety of feed matrixes. Six Youden matched-pair samples were sent to 10 collaborators in Korea, Canada, and the United States. Label claims on the commercial feeds ranged from 0.0077 to 0.22% SMT. The SMT mean recovery as determined from the 5 samples with known analyte content was 99.8%. The within-laboratory relative standard deviation (repeatability) ranged from 0.28 to 4.72%. Among-laboratory (including within-laboratory) relative standard deviation (reproducibility) ranged from 1.26 to 4.87%. The authors recommend the method for AOAC INTERNATIONAL Official First Action status.     

Simultaneous solid-phase extraction of acidic, neutral and basic pharmaceuticals from aqueous samples at ambient (neutral) pH and their determination by gas chromatography-mass spectrometry

Seven polymeric solid-phase extraction (SPE) sorbents were evaluated with regard to their ability to extract acidic, neutral and basic pharmaceuticals and estrogens simultaneously from water at neutral pH. Highest recoveries (70-100%) for the majority of the analytes were obtained with styrene-methacrylate and styrene-N-vinylpyrrolidone co-polymers. The latter one (Oasis HLB) was chosen for further refinement of an extraction method for the quantitative determination of acidic and neutral drugs in surface water samples at detection limits below 1 ng/l. A sequential elution protocol was applied for clean-up and separation of the extracted analytes into fractions suitable for further compound specific processing. The neutral analytes as well as the acidic compounds after derivatisation were quantified by GC-MS. Caffeine, ibuprofen, its metabolites and diclofenac were detected in river water samples in the 1-100 ng/l range.     

Migration of pseudoestrogen bisphenol A from various types of paper with thermochromic prints to artificial sweat solutions

Abstract

Thermochromic inks, materials that change color at a certain temperature, are increasingly used on papers and other materials in the areas of design, commercials, and security printing. Pseudo-estrogen bisphenol A (BPA) may be one of their main compounds present in mass fractions of up to several percent. In this work, the mass fractions of BPA in thermochromic prints on seven types of paper were determined. Migration of BPA from the surface of the thermochromic print to artificial sweat solutions was investigated as well. Total amount of BPA in papers with thermochromic prints was determined by an HPLC-UV method with ultrasonic-assisted extraction in methanol developed and validated in this work. Total amount of BPA, which ranged from 0.126 to 0.778?mg/g, was compared with the amounts extracted under the same conditions in two artificial human sweat solutions, which differed in chemical composition, ionic strength, and pH-value. Mass fractions of BPA extracted with artificial sweat solutions were from 0.047 to 0.175?mg/g with respect to the mass of the paper. On average, the mass fraction of BPA was four times less when extracted with artificial sweat solutions than the maximal amount extracted with methanol. The amounts of extracted BPA raise a concern of health risk through dermal exposure to BPA from thermochromic prints on paper.     

Dialkyltin salts as extractants in methods for the determination of arsenic and phosphorus

Dialkyltin salts are suitable as extractants for various oxygen-containing anions. They are particulary powerful for the extraction of arsenate and phosphate ions, but are also useful for liquid-liquid extraction of anions of dibasic acids. It is shown that the high extraction power of these dialkyltin complexes can be explained by formation of innersphere complexes with the extracted anions. A method is proposed for the separation of arsenic, phosphorus and silicon using dialkyltin salts. Applications to the extraction-spectrophotometric determination of phosphorus and arsenic in vanadium and steel, and to extraction/atomic absorption determinations of arsenic and phosphorus in metals and alloys are surveyed. The use of the dialkyltin salts for the neutron activation determination of arsenic and as active components in membranes of ion-selective electrodes for phosphorus(V) and arsenic(V) is demonstrated.     

Determination of (fluoro)quinolone antibiotic residues in pig kidney using liquid chromatography-tandem mass spectrometry. Part II: intercomparison exercise

A recently in-house validated method for the liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination of eleven (fluoro)quinolone antibiotics (FQs) in pig kidney has been fully validated through an intercomparison exercise. This ring trial involved eight European laboratories and was based on the Commission Decision 2002/657/CE for validation of method and on the IUPAC protocol for method-performances studies. The laboratories data were submitted to a one-way analysis of variance. Satisfactory results were obtained for each FQ with regards to within- and between-laboratory reproducibility and accuracy. The method was validated for the simultaneous qualitative and quantitative determination of the eleven FQs in pig kidney around their maximum residue limit (MRL) as defined in the European Council Regulation 2377/90/EEC.     

Determination of pesticide residues in wine by membrane-assisted solvent extraction and high-performance liquid chromatography–tandem mass spectrometry

The determination of pesticides in food products is an essential issue to guarantee food safety and minimise health risks of consumers. A protocol based on membrane-assisted solvent extraction and liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) that allows the determination of 18 pesticides in red wine at minimum labour effort for sample preparation was developed and validated. Ten millilitres of wine were extracted using 100 μL of toluene filled in a non-porous polyethylene membrane bag which is immersed in the wine sample. After 150 min extraction under stirring, an aliquot of the extraction solution is analysed using HPLC-MS/MS. The limits of quantification ranged from 3 ng/L for Pirimicarb to 1.33 μg/L for Imidacloprid. Quantification by matrix-matched calibration provided relative standard deviations ≤16 % for most of the target pesticides. The linearity of calibration was given over three to four orders of magnitude, which enables the reliable measurement of a broad range of pesticide concentrations, and for each target pesticide, the sensitivity of the protocol meets the maximum residue levels set by legislations at least for wine grapes. Good agreement of results was found when the new method was compared with a standard liquid-liquid extraction protocol. In five wine samples analysed, Carbendazim and Metalaxyl were determined at micrograms per litre concentrations, even in some of the organic wines. Tebuconazol and Cyprodinitril were determined at lower abundance and concentration, followed by Spiroxamin and Diuron.     

电感耦合等离子体发射光谱法测定磷石膏中的水溶性五氧化二磷

建立电感耦合等离子发射光谱法(ICP–OES)测定磷石膏中水溶性五氧化二磷含量的方法。用超声波快速提取磷石膏中的磷,在178.284 nm波长下,用CID固体检测器测定样品溶液的光谱强度。五氧化二磷的质量浓度在0.007~200 mg/L范围内与光谱强度线性关系良好,线性相关系数r=0.999 96,检出限为0.006 9 mg/L。样品加标回收率在98%~102%之间,测定结果的相对标准偏差为0.95%~1.11%(n=6),该方法的测定结果与国标法基本一致。该法简便、快速,适合磷石膏中水溶性五氧化二磷的测定。     

A clean‐up technology for the simultaneous determination of lysophosphatidic acid and sphingosine‐1‐phosphate by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry using a phosphate‐capture molecule,Phos‐tag

Lysophosphatidic acid (LPA) and sphingosine‐1‐phosphate (S1P) are growth factor‐like lipids having a phosphate group. The concentrations of these mediator lipids in blood are considered to be potential biomarkers for early detection of cancer or vascular diseases. Here, we report a method for simultaneous determination of LPA and S1P using Phos‐tag, a zinc complex that specifically binds to a phosphate‐monoester group. Although both LPA and S1P are hydrophilic compounds, we found that they acquire hydrophobic properties when they form complexes with Phos‐tag. Based on this finding, we developed a method for the enrichment of LPA and S1P from biological samples. The first partition in a two‐phase solvent system consisting of chloroform/methanol/water (1:1:0.9, v/v/v) is conducted for the removal of lipids. LPA and S1P are specifically extracted as Phos‐tag complexes at the second partition by adding Phos‐tag. The Phos‐tag complexes of LPA and S1P are detectable by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) and quantifiable based on the relative intensities of ions using 17:0 LPA and C17 S1P as internal standards. The protocol was validated by analyses of these mediator lipids in calf serum, a rat brain and a lung. The clean‐up protocol is rapid, requires neither thin‐layer chromatography (TLC) nor liquid chromatography (LC), and is applicable to both blood and solid tissue samples. We believe that our protocol will be useful for a routine analysis of LPA and S1P in many clinical samples. Copyright © 2010 John Wiley & Sons, Ltd.     

CZE with On-line Micellar Sample Stacking for Determination of Protein Concentration of Biopharmaceuticals

A capillary zone electrophoresis total protein assay was developed and validated in polyethylene oxide (PEO) dynamically coated capillaries. On-line large-volume sample stacking was employed. Protein samples were denatured using SDS and then injected into PEO-filled capillaries. Such treatment enabled injection of a sample volume of ??8% of the total capillary volume and stacking of protein-SDS molecules at the interface between the sample plug and the PEO plug. Results showed that SDS enhanced the sensitivity not only by protein denaturation but also by forming micelles, in which protein-SDS partitioned. Sensitivity of the method was further enhanced through using capillaries with (tenfold) extended detection pathlength. Such strategies resulted in a limit of detection of 0.26 ??g mL^?1 (3.64 nM BSA). A linear relationship between protein concentration and integrated peak area was obtained over a wide concentration range (8.49?C135.87 ??g mL^?1??R ² = 0.995). The method is particularly useful for determination of total protein concentration in chromatography fractions. It overcomes low UV absorptivity of proteins, presence of UV absorbing additives and high salt content. Contrary to conventional methods for determination of protein concentration, this method does not involve an interaction with a dye. Thus, variations due to differences in surface properties among proteins or due to differences in posttranslational modifications of the same protein are eliminated. The protocol was successfully applied for the determination of the concentration of a biopharmaceutical protein rhMBP in chromatography fractions. This protein has been previously produced in milk of transgenic cows and several charge isoforms were detected.