共查询到9条相似文献,搜索用时 0 毫秒
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Jorge L. Guzmán Mar Leticia López Martínez Pedro L. López de Alba Jesús E. Castrejón Durán Víctor Cerdà Martín 《Mikrochimica acta》2006,153(3-4):139-144
1-Naphthylamine (NPA) is one of the main degradation products of pesticides derived from naphthalene, and a well-known bladder
carcinogen in men. The Griess assay is used for NPA determination because of its high sensitivity and selectivity. The azo
dye 4-(sulphophenylazo)-1-naphthylamine is formed, which shows a peak maximum at 540 nm. After optimizing multisyringe flow
injection analysis (MSFIA) parameters, the analytical characteristics of the method were obtained, with a working linear range
of 0.5 to 14 mg L−1, according to the equation A = 0.0738±0.0019 [NPA] + 0.0028 ± 0.0042, r = 0.9997. Values for RSD (%) and Erel (%) were calculated for the concentration levels of 0.5, 6 and 12 mg L−1; values obtained were 1.1, 0.4 and 0.3% for RSD and 0.8, 0.3 and 0.2% for Erel, respectively. LD was 0.01 mg L−1 and LQ was 0.04 mg L−1 NPA. The MSFIA procedure for the determination of NPA was applied to different water samples (well water, tap water, seawater,
and wastewater from the EDAR-1, Palma de Mallorca water treatment plant), with satisfactory results and a throughput of 90
samples per hour. 相似文献
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《Analytical letters》2012,45(15):2897-2913
Abstract A flow injection system for the enzymatic determination of L-malate is described. It is adapted for the analysis of wines and fruit juices by in-line sample dilution. Malate dehydrogenase (MDH) and aspartate aminotransferase (AST) were coimmobilized on controlled pore glass. The NADH generated in the packed bed bienzyme reactor was detected fluorimetrically. Sufficient L-malate conversion could be achieved using the coupled transferase reaction to transform the reaction product oxaloacetate. The linear range of the unmodified flow injection system, 5 – 100 μ M of L-malate, could be increased up to 50 mM by means of zone sampling so that untreated samples could be analyzed directly. From 12 – 20 samples per hour could be analyzed with a standard deviation of less than 2 % depending on variation in the degree of dilution. The activity of the bienzyme reactor decreased less than 4% over an analysis period of 3 weeks with more than 1200 injections. 相似文献
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本文以气体扩散法测氨为例,比较了三种流动注射扩展线性范围方法的性能;讨论了影响分析精度的因素。把微升进样在线稀释技术同气体扩散光度法结合,测定了农药发酵液中氨态氮的含量。方法的回收率为93—106%,每小时可分析60—80个样。 相似文献
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It is the first time that boron has been used as a chromogenic agent to determine aminomethylbenzoic acid (PAMBA) by the fading spectrophotometric method in this paper. The study indicates that at pH 10.00 the absorbance of PAMBA decreases when boric acid (BA) is added to the solution. A simple, rapid, sensitive and reliable novel method based on the product of PAMBA and BA is obtained. The stoichiometric ratio of the product is 1:2. Beer's law is obeyed in the range of PAMBA concentrations of 0.13 ? 38.40 μg/mL at a wavelength of 242 nm (ε242 is 8.1 × 104 L/mol/cm). The equation of linear regression is A = ‐0.06635 – 0.02914C (× 10?5 M), with a linear correlation coefficient of 0.9974. The detection limit is 0.12 μg/mL and RSD 0.11%. The method is successfully applied to the determination of PAMBA in pharmaceutical samples, and average recoveries from pharmaceutical samples and urine samples were between 98.4 ? 102.5%. The other components in these samples do not interfere with the determination by the proposed method. 相似文献
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The QuEChERS method was applied to the determination of pesticide residues in vine (Vitis vinifera) leaves by LC-MSMS. The method was validated in-house for 33 pesticides representing 17 different chemical groups, that are most commonly used in grape production. Recoveries for the pesticides tested ranged from 75 to 104%, and repeatability and reproducibility relative standard deviations (RSDr% and RSDRw%) were less than 20%. The method was applied to the analysis of pesticide residues in 17 market brands of vine leaves processed according to three different preservation methods and sampled from the Lebanese market. Dried vine leaves were more contaminated with pesticide residues than those preserved in brine or stuffed vine leaves. The systemic fungicides were the most frequently detected among all the phytosanitary compounds usually applied to grape production. Brine-preserved and stuffed vine leaves contained lower concentrations of the residues but still contained a cocktail of different pesticides. 相似文献
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《Analytical letters》2012,45(12):2305-2327
Abstract The automation of the discontinuous (batch) method for kinetic stucfies using flow-injection analysis (FIA) is described. Aliquots of the reaction mixture are automatically injected in an appropriate manifold and the kinetic profile of the reaction is obtained as a series of absorbance peaks. Observed reaction rate constants are calculated using the Guggenheim and non-linear fitting approaches. The new method is evaluated in the kinetic study of the acid hydrolysis of N4-acetylsulfanilamide by colorimetric monitoring of sulfanilamide, the alkaline hydrolysis of acetylsalicylic acid (aspirin) by colorimetric monitoring of salicylate, and the enzymic hydrolysis of phenyl phosphate with alkaline phosphatase by colorimetric monitoring of phosphate. The automated flow-injection batch method can be used in kinetic studies of reactions with t1/2 greater than 200 s. 相似文献
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Clemente Bretti Concetta De Stefano Claudia Foti Silvio Sammartano 《Journal of solution chemistry》2006,35(9):1227-1244
The protonation constants of phthalate were determined in aqueous NaCl (0.1 ≤ I ≤ 5,mol⋅L−1) and in aqueous Me4NCl (0.1 mol⋅L−1 ≤ I ≤ 3,mol⋅L−1) at t = 25,∘C. Experimental data were employed in conjunction with literature data from studies in different ionic media (Et4NI: 0 ≤ I ≤ 1,mol⋅L−1; NaClO4: 0.05 mol⋅L−1 ≤ I ≤ 2,mol⋅L−1)to study the dependence on ionic strength using different models, such as the SIT and Pitzer equations, and an Extended Debye-Hückel type equation. Experimental calorimetric data in NaCl and protonation constants at different temperatures in Et4NI (5 ≤ t ≤ 45∘C) and in NaClO4 (15 ≤ t ≤ 35 ∘C) were also used to study their dependence on temperature. Recommended equilibrium data are reported together with a short discussion of a prospective protocol for drawing these data. 相似文献