scholarly journals A Modifiedo-Phthalaldehyde Fluorometric Analytical Method for Ultratrace Ammonium in Natural Waters Using EDTA-NaOH as Buffer

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Hongzhi Hu ◽  
Ying Liang ◽  
Shuo Li ◽  
Qing Guo ◽  
Chancui Wu
Keyword(s):  
Reaction Time ◽  
Detection Limit ◽  
Analytical Method ◽  
Natural Waters ◽  
Reagent Concentration ◽  
Method Detection Limit ◽  
Experimental Parameters ◽  
Ph Range ◽  
Optimal Ph ◽  
Disodium Ethylenediaminetetraacetate

In the existence of appropriate amount of disodium ethylenediaminetetraacetate (EDTA), precipitation would not occur in seawater and other natural waters even if the sample solution was adjusted to strong basicity, and the NH3-OPA-sulfite reaction at the optimal pH range could be used to determine ammonium in natural waters. Based on this, a modifiedo-phthalaldehyde fluorometric analytical method has been established to determine ultratrace ammonium in natural waters. Experimental parameters, including reagent concentration, pH, reaction time, and effect of EDTA, were optimized throughout the experiments based on univariate experimental design. The results showed that the optimal pH range was between 10.80 and 11.70. EDTA did not obviously affect the fluorometric intensity. The linearity range of the proposed method was 0.032–0.500 µmol/L, 0.250–3.00 µmol/L, and 1.00–20.0 µmol/L at the excitation/emission slit of 3 nm/5 nm, 3 nm/3 nm, and 1.5 nm/1.5 nm, respectively. The method detection limit was 0.0099 µmol/L. Compared to the classical OPA method, the proposed method had the advantage of being more sensitive and could quantify ultratrace ammonium without enrichment.

scholarly journals Simple and Fast Methods Based on Solid-Phase Extraction Coupled to Liquid Chromatography with UV Detection for the Monitoring of Caffeine in Natural, and Wastewater as Marker of Anthropogenic Impact

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Sònia Moret ◽  
Manuela Hidalgo ◽  
Juan M. Sanchez
Keyword(s):  
Detection Limit ◽  
Solid Phase Extraction ◽  
Natural Waters ◽  
Wastewater Treatment Plants ◽  
Solid Phase ◽  
Sample Volume ◽  
Uv Detection ◽  
Phase Extraction ◽  
Method Detection Limit ◽  
Spe Method

Two concentration methods for fast and routine determination of caffeine (using HPLC-UV detection) in surface, and wastewater are evaluated. Both methods are based on solid-phase extraction (SPE) concentration with octadecyl silica sorbents. A common “offline” SPE procedure shows that quantitative recovery of caffeine is obtained with 2 mL of an elution mixture solvent methanol-water containing at least 60% methanol. The method detection limit is 0.1 μg L−1 when percolating 1 L samples through the cartridge. The development of an “online” SPE method based on a mini-SPE column, containing 100 mg of the same sorbent, directly connected to the HPLC system allows the method detection limit to be decreased to 10 ng L−1 with a sample volume of 100 mL. The “offline” SPE method is applied to the analysis of caffeine in wastewater samples, whereas the “on-line” method is used for analysis in natural waters from streams receiving significant water intakes from local wastewater treatment plants.

Divalent cations speciation with three phosphonate ligands in the pH-range of natural waters

Talanta ◽  
1997 ◽  
Vol 44 (5) ◽  
pp. 897-907 ◽  
Author(s):  
Véronique Deluchat ◽  
Jean-Claude Bollinger ◽  
Bernard Serpaud ◽  
Claude Caullet
Keyword(s):  
Natural Waters ◽  
Divalent Cations ◽  
Ph Range ◽  
Phosphonate Ligands

scholarly journals RISIKO KESEHATAN PAJANAN BENZENA, TOLUENA DAN XYLENA PETUGAS PINTU TOL

2016 ◽  
Vol 11 (2) ◽  
pp. 188 ◽  
Author(s):  
Bambang Wispriyono ◽  
Eko Handoyo
Keyword(s):  
Detection Limit ◽  
Health Risks ◽  
Risk Groups ◽  
Health Impacts ◽  
Method Detection Limit ◽  
Cross Sectional ◽  
Risk Management System ◽  
Environmental Health Risk ◽  
Benzene Concentration ◽  
Benzene Toluene

<p>Efek negatif dari polusi udara terhadap kesehatan manusia banyak diteliti termasuk polusi akibat sistem transportasi. Emisi kendaraan bermotor menghasilkan Benzena, Toluena dan Xylena (BTX) yang merupakan bahan kimia yang bersifat karsinogenik dan petugas pintu tol merupakan kelompok berisiko terpajan BTX. Penelitian bertujuan mengetahui risiko kesehatan akibat pajanan BTX pada petugas pintu tol. Desain penelitian adalah <em>cross-sectional</em> dengan pendekatan Analisis Risiko Kesehatan Lingkungan (ARKL) dan  faktor-faktor antropometri. Hasil penelitian menunjukkan pada pintu tol rata-rata konsentrasi (mean<span style="text-decoration: underline;">+</span>SD) benzena sebesar 0,00167<span style="text-decoration: underline;">+</span>0,000056 mg/m<sup>3</sup>, toluena sebesar 0,00124<span style="text-decoration: underline;">+</span>0.000049 mg/m<sup>3</sup> dan xylena sebesar 0,00147<span style="text-decoration: underline;">+</span>0,000063 mg/m<sup>3</sup> sedangkan pada kantor administrasi konsentrasi tidak terdeteksi oleh alat (<em>Method Detection Limit</em>). Rata-rata risiko non karsinogenik (RQ) BTX pada petugas pintu tol lebih tinggi secara signifikan dibandingkan dengan rata-rata RQ BTX petugas administrasi. Risiko kesehatan non karsinogenik dan karsinogenik belum menunjukkan adanya risiko kesehatan yang signifikan. Upaya pencegahan berupa pengelolaan manajemen risiko untuk pengendalian risiko bahan berbahaya di lingkungan perlu ditingkatkan.</p><p> </p><p><strong>Kata Kunci:</strong> Pintu Tol, Benzena, Toulena, Xylena</p><p> </p><p>The researches of BTX (Benzene, Toluene and Xylene) related to the health impacts have been done and published in any publications. One of the risk groups is toll gate’s workers who have been exposed every day with BTX. The design of this study is cross-sectional with Environmental Health Risk Analysis to determine the magnitude of health risks of BTX on the toll gate. The results showed at the toll workers’s respondents have  benzene concentration 0.00167+0.000056 mg/m<sup>3</sup>, toluene 0.00124+0.000049 mg/m<sup>3</sup> and xylene 0.00147+0,000063 mg/m<sup>3</sup> respectively, while in the administrative office’s respondents, BTX was undetectable (Minimum Detection Limit). The average RQ of toll gate respondents was significantly higher than administrative office’s respondents. In conclusion, the risk of all workers have the RQ ≤ 1. Non carcinogenic and carcinogenic health risks to all toll gate’s workers recently have not shown any risk yet. Nevertheless, risk management system should be developed and improved.</p><p> </p><p><strong>Keywords</strong>: Toll Gate, Benzene, Toulene, Xylene</p>

scholarly journals Optimal pH in chlorinated swimming pools – balancing formation of by-products

2013 ◽  
Vol 11 (3) ◽  
pp. 465-472 ◽  
Author(s):  
Kamilla M. S. Hansen ◽  
Hans-Jørgen Albrechtsen ◽  
Henrik R. Andersen
Keyword(s):  
Body Fluid ◽  
Product Formation ◽  
Swimming Pools ◽  
Batch Experiments ◽  
Ph Values ◽  
Precursor Ratio ◽  
Decreasing Ph ◽  
Ph Range ◽  
By Products ◽  
Optimal Ph

In order to identify the optimal pH range for chlorinated swimming pools, the formation of trihalomethanes, haloacetonitriles and trichloramine was investigated in the pH-range 6.5–7.5 in batch experiments. An artificial body fluid analogue was used to simulate bather load as the precursor for by-products. The chlorine-to-precursor ratio used in the batch experiments influenced the amounts of by-products formed, but regardless of the ratio the same trends in the effect of pH were observed. Trihalomethane formation was reduced by decreasing pH, but haloacetonitrile and trichloramine formation increased. To evaluate the significance of the increase and decrease of the investigated organic by-products at the different pH values, the genotoxicity was calculated based on literature values. The calculated genotoxicity was approximately at the same level in the pH range 6.8–7.5 and increased when pH was 6.7 or lower. An optimal pH range for by-products formation in swimming pools was identified at pH 7.0–7.2. In the wider pH range (pH 6.8–7.5), the effect on by-product formation was negligible. Swimming pools should never be maintained at lower pH than 6.8 since formation of both haloacetonitriles and trichloramine increase significantly below this value.

Graphite Furnace Atomic Absorption Method for the Determination of Lead in Sugars and Syrups

1994 ◽  
Vol 77 (5) ◽  
pp. 1288-1292 ◽  
Author(s):  
Nancy J Miller-Ihli
Keyword(s):  
Detection Limit ◽  
Atomic Absorption ◽  
Graphite Furnace ◽  
Absorption Spectrometry ◽  
Magnesium Nitrate ◽  
Method Detection Limit ◽  
High Fructose ◽  
Graphite Furnace Atomic Absorption ◽  
Characteristic Mass

Abstract A method was developed for the determination of lead in sugars and syrups. Samples are wet-ashed with a nitric acid–hydrogen peroxide procedure and analyzed by graphite furnace atomic absorption spectrometry. The method involves the use of magnesium nitrate as a matrix modifier, air ashing, platform atomization, and quantitation by peak area measurements with direct calibration against aqueous standards. The instrumental detection limit (based on 3.29σ) was 10 pg, or 0.5 μg/L for a 20 μL injection, corresponding to a method detection limit of 3.3 ng/g sugar. The characteristic mass was approximately 12 pg. This method was validated by analyzing sucrose and high-fructose corn syrup samples spiked with known quantities of lead. The average recovery was 101 ± 6%.

Analysis by Liquid Chromatography of Fusarochromanone (TDP-1) Added to Corn and Wheat

1994 ◽  
Vol 77 (5) ◽  
pp. 1179-1183 ◽  
Author(s):  
Yichun Xu ◽  
C J Mirocha ◽  
W Xie
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Analytical Method ◽  
Ammonium Hydroxide ◽  
Fluorescence Properties ◽  
Layer Chromatography

Abstract An analytical method was developed for the detection of fusarochromanone (TDP-1) in com and wheat by liquid chromatography. Extraction was done with methanol-water-ammonium hydroxide (90 + 10 + 2), and cleanup was by elution through a silica Sep-Pak cartridge. The limit of sensitivity of TDP-1, detected on the basis of its fluorescence properties, is 200 pg, whereas the detection limit of the method for corn and wheat is 5 ng/g. The average recoveries of TDP-1 added at 5,25,100,500, and 1000 ppb were 86% for corn and 83% for wheat. Confirmation was done by thin-layer chromatography.

scholarly journals Development of Substrate Degradation Enzyme Therapy for Mucopolysaccharidosis IVA Murine Model

2019 ◽  
Vol 20 (17) ◽  
pp. 4139 ◽  
Author(s):  
Kazuki Sawamoto ◽  
Shunji Tomatsu
Keyword(s):  
Positive Impact ◽  
Bone Lesion ◽  
Enzyme Therapy ◽  
Bone Pathology ◽  
Mucopolysaccharidosis Iva ◽  
Enzyme Replacement ◽  
Substrate Degradation ◽  
Mps Iva ◽  
Ph Range ◽  
Optimal Ph

Mucopolysaccharidosis IVA (MPS IVA) is caused by a deficiency of the lysosomal enzyme N-acetylgalactosamine-6-sulfate sulfatase (GALNS). Conventional enzyme replacement therapy (ERT) is approved for MPS IVA. However, the fact that the infused enzyme cannot penetrate avascular lesions in cartilage leads to minimal impact on the bone lesion. Moreover, short half-life, high cost, instability, and narrow optimal pH range remain unmet challenges in ERT. Thermostable keratanase, endo-β-N-acetylglucosaminidase, has a unique character of a wide optimal pH range of pH 5.0–7.0. We hypothesized that this endoglycosidase degrades keratan sulfate (KS) polymer in circulating blood and, therefore, ameliorates the accumulation of KS in multiple tissues. We propose a novel approach, Substrate Degradation Enzyme Therapy (SDET), to treat bone lesion of MPS IVA. We assessed the effect of thermostable keratanase on blood KS level and bone pathology using Galns knock-out MPS IVA mice. After a single administration of 2 U/kg (= 0.2 mg/kg) of the enzyme at 8 weeks of age via intravenous injection, the level of serum KS was significantly decreased to normal range level, and this suppression was maintained for at least 4 weeks. We administered 2 U/kg of the enzyme to MPS IVA mice every fourth week for 12 weeks (total of 3 times) at newborns or 8 weeks of age. After a third injection, serum mono-sulfated KS levels were kept low for 4 weeks, similar to that in control mice, and at 12 weeks, bone pathology was markedly improved when SDET started at newborns, compared with untreated MPS IVA mice. Overall, thermostable keratanase reduces the level of KS in blood and provides a positive impact on cartilage lesions, demonstrating that SDET is a novel therapeutic approach to MPS IVA.

A Survey of Benzene in Fruits and Retail Fruit Juices,Fruit Drinks, and Soft Drinks

1992 ◽  
Vol 75 (2) ◽  
pp. 334-340 ◽  
Author(s):  
Denis B Page, ◽  
Henry B.S Conacher, ◽  
Dorcas Weber, ◽  
Gladys Lacroix,
Keyword(s):  
Gas Chromatography ◽  
Detection Limit ◽  
Capillary Gas Chromatography ◽  
Soft Drinks ◽  
Fruit Juices ◽  
Mineral Waters ◽  
Headspace Sampling ◽  
Method Detection Limit ◽  
Selected Ion Monitoring ◽  
Full Scan

Abstract Recent findings of benzene In several fruit-flavored mineral waters at low μg/kg levels, reportedly arising from added benzoate, have prompted a survey of various fruits, juices, and drinks for traces of benzene. Headspace sampling, capillary gas chromatography, and mass spectrometrlc detection enabled detection with confirmation (full-scan spectrum) of benzene as low as 0.03 μg/kg. With selected Ion monitoring, the method detection limit was 0.02 μg/kg, I.e., 3 times the analytical blank, in total, 97 samples were analyzed. Benzene was found at levels ranging from 0.018 to 3.83 μg/kg. Samples labeled to contain added benzoate or believed to contain natural benzoate, such as cranberries, were found to contain benzene at higher levels (n = 41, av. 0.66 μg/kg) than other samples (n = 32, av. 0.082 μg/kg). Average levels of benzene In fruits (as expressed juice), In juices with and without benzoate, In noncarbonated drinks with and without benzoate, and in soft drinks with and without benzoate were 0.042,0.672,0.056,0.395, 0.116,0.793, and 0.062 μg/kg, respectively

The Synthesis of Levulinic Acid Synthesis from Glucose Using ZSM-5 Zeolite Catalyst

2013 ◽  
Vol 291-294 ◽  
pp. 782-785 ◽  
Author(s):  
Jun Ping Zhuang ◽  
Chun Sheng Pang ◽  
Ying Liu
Keyword(s):  
Reaction Time ◽  
Levulinic Acid ◽  
Zeolite Catalyst ◽  
Maximum Yield ◽  
Value Added ◽  
Acid Synthesis ◽  
Temperature Reaction ◽  
Experimental Parameters ◽  
Fuels And Chemicals ◽  
Broad Variety

Levulinic acid （LA）is a highly versatile platform chemical that can be converted into a broad variety of value-added fuels and chemicals. LA can be produced from the botanic biomass by hydrolyzing. The aim of the present study is to investigate the conversion of glucose to LA by ZSM-5 zeolite catalyst for LA production and optimized to obtain the maximum yield of LA. The main experimental parameters are the amount of ZSM-5 zeolite added, reaction temperature, reaction time and concentration of glucose. The results showed that the optimization of the conversion of glucose to LA by ZSM-5 zeolite. An optimized LA yield was obtained at 190 °C for 2.5 h with 3 g ZSM-5 zeolite catalys and the highest LA yield was 69. 32%.

Factors influencing the inorganic speciation of trace metal cations in fresh waters

1999 ◽  
Vol 50 (4) ◽  
pp. 367 ◽  
Author(s):  
Jonathan P. Kim ◽  
Keith A. Hunter ◽  
Malcolm R. Reid
Keyword(s):  
Natural Waters ◽  
Major Ions ◽  
Divalent Cations ◽  
Ion Composition ◽  
High Ph ◽  
River Waters ◽  
Inorganic Complexes ◽  
Effects Of Ph ◽  
Ph Range ◽  
Inorganic Speciation

The effects of pH and major ion composition on the chemical speciation of the divalent cations of Co, Ni, Cu, Zn, Pb and Cd have been examined after consideration of the available thermodynamic database for solution complexes of these ions. Calculations were made for two model river waters representing the 1% and 99% extremes in composition of global river waters. The results show that inorganic speciation behaviour is of two characteristic types: (a) Cu, Zn and Co are dominated by bis-hydroxy- complexes at high pH and show the greatest reduction in the fraction of free aquo ion with increasing pH; (b) Pb, Ni and Cd are dominated by carbonato- complexes at high pH and show a more gradual decrease in the fraction of free aquo ion with increasing pH. For Cu, Pb and Ni significant fractions of the labile forms of these metal ions are present as inorganic complexes in the pH range of most natural waters, whereas for Zn, Co and Cd this is true only at moderately high pH (pH >7.5). Complexing with the major ions SO42– and Cl– is important only at low pH in river waters of high ionic strength.

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