Quantitation of free sulfate and total sulfoesters in human breast milk by ion chromatography

A method for the assay of free sulfate and total sulfoesters in human breast milk by ion chromatography is described. After incubation in 1 M hydrochloric acid at 95 degrees C for 90 min, hydrolytic cleavage of sulfoester standards was essentially complete. The increase in free sulfate after hydrolysis was used as a measure of total acid-labile sulfoesters. We found that this fraction [222 +/- 16 mumol/l (mean +/- standard error), n = 29] comprised 87% of the total sulfate in mature milk. Free sulfate (35 +/- 3 mumol/l) therefore makes only a small contribution to the total sulfate pool available to human infants.     

Indirect atomic absorption spectrometric determination of sulfate in human blood serum.

An indirect method for the determination of sulfate by atomic absorption spectrometry (AAS) is described. Sulfate forms a stable ion-association complex, [Cu(neocuproine)2]2+(SO4(2-)), in neutral medium, which can be extracted into isobutyl methyl ketone in the presence of a polar medium (methanol) with an efficiency higher than 98.0% and the extract can be analysed directly for copper (and hence indirectly for sulfate) by AAS. Measurement of the copper atomic absorption signal from the organic phase allows the indirect determination of 0.14-1.12 micrograms ml-1 of sulfate, giving a 450-fold increase in sensitivity over the conventional method of precipitation with barium. The limit of detection (3 sigma) is 3.2 ng ml-1 which is better than that of ion chromatography (0.15 micrograms ml-1). Indirect AAS allows the accurate assay of inorganic sulfate anion in biological fluids and tissues. The sulfate concentration determined by the proposed method in human blood serum (n = 6 in each instance) was 35.4-43.3 micrograms ml-1 in normal persons, 50.3-62.5 micrograms ml-1 in jaundice patients and 83.3-155.6 micrograms ml-1 in diabetic patients. A good correlation between measured sulfate and the sulfate added to blood serum was obtained.     

DX-300离子色谱测定山地冰川雪冰中的有机酸与无机酸阴离子

 利用AS4A SC分离柱 ,AG4A SC保护柱 ,ASRS Ⅱ抑制器 ,TAC 2阴离子富集柱和ATC 1阴离子捕集柱 ,以四硼酸钠 (Na2 B4O7)为淋洗液试剂 ,2 5mmol/LH2 SO4为化学抑制的再生液 ,采用梯度淋洗方式 ,对中国天山乌鲁木齐河源一号冰川雪冰中的生物有机酸和无机酸阴离子进行了测试分析。 2mL雪冰融水样品可在 16min内通过一次进样检测出氟离子、乙酸根离子、甲酸根离子、丙酮酸根离子、一氯乙酸根离子、氯离子、亚硝酸根离子、溴离子、硝酸根离子、磷酸根离子、硫酸根离子和草酸根离子共 10多种有机酸和无机酸阴离子。     

Fluorimetric determination of the levels of urinary neopterin and serum thiobarbituric acid reactive substances in the nonagenarians

Twelve self-sustaining nonagenarians, 10 women and two men, aged 94+/-3 years, and eight institutionalised nonagenarians, eight women, aged 91+/-1 year as well as 11 control subjects, seven women and four men, aged 84+/-5 years entered the study. Urinary neopterin, an indicator of systemic immune activation, and serum thiobarbituric acid reactive substances (TBARS), a marker of lipoperoxidation, were determined initially, and collection of the blood and urine samples was repeated at 3-month interval. Neopterin was measured in the urine specimens by reversed-phase high performance liquid chromatography. A C(18) reversed-phase column 3.3x150 mm, 5 mum-diameter packing Separon SGX was used. Potassium phosphate buffer (15 mmol l(-1), pH 6.4) at flow rate of 0.8 ml min(-1) was used as mobile phase. After centrifugation (5 min, 1300xg) and diluting 100 mul of urine specimens with 1.0 ml of mobile phase containing 2 g of disodium-EDTA per litre, a 20 mul sample was injected on a column. Neopterin was identified by its native fluorescence (353 nm excitation, 438 nm emission). Creatinine was determined by Jaffé kinetic reaction after dilution of sample 1:50 (v/v). The concentration of neopterin in urine was expressed as neopterin/creatinine ratio (mumol mol(-1) creatinine). TBARS were determined spectrofluorometrically using LS-5 spectrofluorimeter (excitation wavelength 528 nm, emission wavelength 558 nm) after extraction with n-butanol treatment with thiobarbituric acid. The significance of differences between nonagenarians and control group was examined by ANOVA-Kruskal-Wallis tests, using statistical software NCSS 6.0.21 (Kaysville, UT, 1996). The decision on significance was based on P=0.05. Urinary neopterin was significantly higher in institutionalised compared to self-sustaining subjects and controls (625+/-565 vs. 203+/-63 mumol mol(-1) creatinine, and 198+/-128 mumol mol(-1) creatinine, respectively, P=0.006). The serum TBARS were higher in both groups of nonagenarians (3.23+/-1.16 mumol l(-1) and 2.69+/-0.39 vs. 2.12+/-0.83 mumol l(-1) for the self-sustaining, institutionalised and controls, respectively, P=0.023). We conclude that the fluorimetric determinations of urinary neopterin and serum TBARS can be useful for the monitoring health status in the elderly patients.     

Simple method for the determination of inorganic sulfate in human serum and urine using single-column ion chromatography

A single-column ion chromatographic assay with conductivity detection was developed to determine inorganic sulfate concentrations in human plasma and urine samples. Plasma samples were ultrafiltered to remove proteins. Plasma ultrafiltrate and urine samples were diluted prior to injection onto the anion-exchange column. The described method is simple, fast, sensitive and reproducible and was used to study the effect of subchronic administration of acetaminophen on the plasma concentrations and urinary excretion of inorganic sulfate in healthy volunteers.     

Speciation of chromium by coupled column HPLC-ICP-MS – the effects of interfering ions

ICP-MS is used as an element selective detector for chromium species in aquatic samples using a coupled columm system consisting of a cation guard column and an anion column. The effects of large concentrations of disturbing ions, like NO(3)(-), Cl(-), CO(3)(2-) and SO(4)(2-), are discussed and the comparison with the use of different chromium isotopes for data acquisition is given. Quite low concentrations such as 100 mg/l of CO(3)(2-), 10 mg/l Cl(-) and even 5 mg/l SO(4)(2-) can cause an overestimation of chromium if not properly resolved1995 / Accepted: 24 October 1995     

Novel sulfate ion-selective polymeric membrane electrode based on a derivative of pyrilium perchlorate

A sulfate ion-selective PVC membrane sensor based on 4-(4-bromophenyl)-2,6-diphenylpyrilium perchlorate (BDPP) as a novel sensing material is successfully developed. The electrode shows a good selectivity for sulfate ion with respect to common organic and inorganic anions. The sensor exhibits a good linear response with slope of -28.9+/-0.5 mV per decade over the concentration range of 1.0x10(-6)-1.0x10(-2) M, and a detection limit of 8.0x10(-7) M of SO(4)(2-) ions. The electrode response is independent of pH in the range of 4.0-9.0. The proposed sensor was applied as an indicator electrode in potentiometric titration of sulfate and barium ions, and to the determination of zinc in zinc sulfate tablets.     

EXAFS investigation of U(VI), U(IV), and Th(IV) sulfato complexes in aqueous solution

The local structure of U(VI), U(IV), and Th(IV) sulfato complexes in aqueous solution was investigated by U-L(3) and Th-L(3) EXAFS spectroscopy for total sulfate concentrations 0.05 < or = [SO(4)(2-)] < or = 3 M and 1.0 < or = pH < or = 2.6. The sulfate coordination was derived from U-S and Th-S distances and coordination numbers. The spectroscopic results were combined with thermodynamic speciation and density functional theory (DFT) calculations. In equimolar [SO(4)(2-)]/[UO(2)(2+)] solution, a U-S distance of 3.57 +/- 0.02 Angstrom suggests monodentate coordination, in line with UO(2)SO(4)(aq) as the dominant species. With increasing [SO(4)(2-)]/[UO(2)(2+)] ratio, an additional U-S distance of 3.11 +/- 0.02 Angstrom appears, suggesting bidentate coordination in line with the predominance of the UO(2)(SO(4))(2)(2-) species. The sulfate coordination of Th(IV) and U(IV) was investigated at [SO(4)(2-)]/[M(IV)] ratios > or = 8. The Th(IV) sulfato complex comprises both, monodentate and bidentate coordination, with Th-S distances of 3.81 +/- 0.02 and 3.14 +/- 0.02 Angstrom, respectively. A similar coordination is obtained for U(IV) sulfato complexes at pH 1 with monodentate and bidentate U-S distances of 3.67 +/- 0.02 and 3.08 +/- 0.02 Angstrom, respectively. By increasing the pH value to 2, a U(IV) sulfate precipitates. This precipitate shows only a U-S distance of 3.67 +/- 0.02 Angstrom in line with a monodentate linkage between U(IV) and sulfate. Previous controversially discussed observations of either monodentate or bidentate sulfate coordination in aqueous solutions can now be explained by differences of the [SO(4)(2-)]/[M] ratio. At low [SO(4)(2-)]/[M] ratios, the monodentate coordination prevails, and bidentate coordination becomes important only at higher ratios.     

Simultaneous ion-exclusion chromatography and cation-exchange chromatography of anions and cations in environmental water samples on a weakly acidic cation-exchange resin by elution with pyridine-2,6-dicarboxylic acid

A non-suppressed conductivity detection ion chromatographic method using a weakly acidic cation-exchange column (Tosoh TSKgel OApak-A) was developed for the simultaneous separation and determination of common inorganic anions (Cl-, NO3- and SO4(2-)) and cations (Na+, NH4+, K+, Mg2+ and Ca2+). A satisfactory separation of these anions and cations on the weakly acidic cation-exchange column was achieved in 25 min by elution with a mixture of 1.6 mmol L-1 pyridine-2,6-dicarboxylic acid and 8.0 mmol L-1 18-crown-6 at flow rate of 1.0 mL min-1. On this weakly acidic cation-exchange resin, anions were retained by an ion-exclusion mechanism and cations by a cation-exchange mechanism. The linear range of the peak area calibration curves for all analytes were up to two orders of magnitude. The detection limits calculated at S/N = 3 ranged from 0.25 to 1.9 mumol L-1 for anions and cations. The ion-exclusion chromatography-cation-exchange chromatography method developed in this work was successfully applied to the simultaneous determination of major inorganic anions and cations in rainwater, tap water and snow water samples.     

Separation of inorganic anions on a triazole-functionalized ion exchanger in ion chromatography

The retention behavior of inorganic anions on a triazole-based stationary phase was first examined in ion chromatography. It was initially designed for hydrophilic interaction liquid chromatography and was simply prepared by introducing the triazole groups onto the surface of silica gel via click chemistry. Effective separation of common inorganic anions, including iodate, chloride, bromide, nitrate and iodide, was achieved with Na(2)SO(4) eluent. The logarithm of the retention factor of analytes was observed to be linear with the logarithm of the eluent concentration, and the slopes of the plots were almost the same as those of the ideal theoretical value. The eluent pH value in the range of 3.4-7.0 had little effect on the separation. The utility of the column was demonstrated for the determination of UV-absorbing anions in saliva and tap water.     

Theoretical and experimental investigation on the oxidation of gallic acid by sulfate radical anions

By monitoring the decay of SO4*- after flash photolysis of aqueous solutions of S2O82- at different pH values, the kinetics of the reaction of SO4*- radicals with gallic acid and the gallate ion was investigated. The bimolecular rate constants for the reactions of the sulfate radicals with gallic acid and the gallate ion were found to be (6.3 +/- 0.7) x 10(8) and (2.9 +/- 0.2) x 10(9) M(-1) s(-1), respectively. On the basis of the oxygen-independent second-order decay kinetics and on their absorption spectra, the organic radicals formed as intermediates of these reactions were assigned to the corresponding phenoxyl radicals. DFT calculations in the gas phase and aqueous solution support formation of the phenoxyl radicals by H abstraction from the phenols to the sulfate radical anion. The observed recombination of the phenoxyl radicals of gallic acid to yield substituted biphenyls and quinones is also supported by the calculations. HPLC/MS product analysis showed formation of one of the predicted quinones.     

Strong inclusion of inorganic anions into β-cyclodextrin immobilized to gold electrode

The inclusion of inorganic anions such as SO(4)(2-), NO(3)(-), and HPO(4)(2-) into the cavity of β-cyclodextrin monolayers on Au was examined by X-ray photoelectron spectroscopy (XPS), a quartz crystal microbalance (QCM), and chronocoulometric measurements of the competitive inclusion with ferrocene. The inclusion amounts of ferrocence in 0.2 M Na(2)SO(4), NaNO(3), and Na(2)HPO(4) solutions were less than 6% of the adsorption amount of β-cyclodextrin on Au, resulting in the apparent inhibition of the ferrocene redox reaction. The surface association constants of these anions reached about 10 on a logarithmic scale and were much higher than those for the inclusion of common organic guest compounds. A stronger anion inclusion was also demonstrated by the QCM response corresponding to the replacement of a preincluded organic guest with sulfate upon the injection of the sulfate solution. Quantitative analysis of the XPS data suggested a 1:1 association for each of these anions per surface β-cyclodextrin. There was no detectable inclusion for ClO(4)(-), Cl(-), and Br(-).     

单一阴离子交换柱同时分离有机酸和无机阴阳离子

研究了用乙二胺四乙酸（ＥＤＴＡ）作淋洗液时，性质迥异的有机酸、无机阴离子和碱土金属离子（Ｃａ＾２＋、Ｍｇ＾２＋）在同一阴离子交换柱上的同时分离以及保留机理，结果表明，在离子交换机理之外，非离子交换机理对有机酸及钙镁的ＥＤＴＡ络阴郭的保留行为起一定的辅助作用，９种有机酸和无机阴阳离子在１０ｍｉｎ内得到了较好的分离。各离子的电导检测灵敏度在１０＾－９至１０＾－１１ｍｏｌ，能满足环境和食吕分析的要求。     

固相萃取-离子色谱法测定甘蔗糖蜜及糖蜜酒精废液中的非氮有机酸和无机阴离子

建立了固相萃取-离子色谱测定甘蔗糖蜜及糖蜜酒精废液中乙酸、乳酸、琥珀酸、苹果酸、酒石酸、草酸、富马酸、柠檬酸、乌头酸等非氮有机酸和盐酸根、硫酸根、磷酸根等3种无机阴离子的方法。样品稀释液经强阴离子(SAX)固相萃取小柱净化除去糖类和色素等干扰基质,再用稀KOH溶液洗脱,经0.45 μm水膜过滤后,用IonPac AS15阴离子分离柱、KOH溶液梯度淋洗-抑制电导检测分离分析。考察了固相萃取小柱对待测离子的保留和洗脱条件。实验结果表明,除乙酸和乳酸的分离不完全、苹果酸与琥珀酸的组分重叠外,其余组分可达到完全分离,被测组分的浓度与其峰高在一定的范围呈良好的线性关系,检出限均低于0.20 mg/L,相对标准偏差(RSD)小于6.7%。测定了2种甘蔗糖蜜和1种糖蜜酒精废液中有机酸及无机阴离子,结果满足检测的要求,样品中各组分的加标回收率为94%～109%。     

高效液相色谱-间接光度检测法测定体液中西梭霉素

采用高效液相色谱－间接光度检测法（ＨＰＬＣ－ＩＰＤ）,在流动相中加入具有紫外检测响应的检测剂烟酰胺,用紫外检测器直接测定体液中无紫外吸收的西梭霉素含量。固定相为ＳｐｈｅｒｉｓｏｒｂＣ１８,流动相为甲醇－乙腈－水（２０∶１０∶７０）,内含磷酸０．０５ｍｏｌ／Ｌ、烟酰胺０．５ｍｍｏｌ／Ｌ、庚烷磺酸钠５ｍｍｏｌ／Ｌ。血清样品中西梭霉素平均回收率为９６．９２％±４．６３％,日内和日间变异系数分别为４．７５％和５．６５％。     

Quantification of the plant-derived hallucinogen Salvinorin A in conventional and non-conventional biological fluids by gas chromatography/mass spectrometry after Salvia divinorum smoking

A gas chromatography method with mass spectrometric detection is described for the determination of Salvinorin A, the main active ingredient of the hallucinogenic mint Salvia divinorum. The method was validated in plasma, urine, saliva and sweat using 17-alpha-methyltestosterone as internal standard. The analytes were extracted from biological matrices with chloroform/isopropanol (9:1, v/v). Chromatography was performed on a 5% phenyl methyl silicone capillary column and analytes were determined in the selected ion monitoring mode. The method was validated over the concentration range 0.015-5 microg/mL plasma, urine and saliva and 0.01-5 microg/patch in the case of sweat. Mean recoveries ranged between 77.1 and 92.7% for Salvinorin A in different biological matrices, with precision and accuracy always better than 15%. The method was applied to the analysis of urine, saliva and sweat from two consumers after smoking 75 mg plant leaves to verify the presence of the active ingredient of S. divinorum in human biological fluids as a biomarker of plant consumption. Salvinorin A was detected in urine (2.4 and 10.9 ng/mL) and saliva (11.1 and 25.0 ng/mL), but not in sweat patches from consumers.     

离子色谱法分析保险粉工业回收甲酸钠中的阴离子

利用单柱阴离子交换色谱法测定了保险粉工业回收产品中的甲酸,Cl－,SO,NO,羟乙基硫代硫酸盐,SO和S2O。以1．8mmol／L邻苯二甲酸和1．35mmol／L三羟甲基氨基甲烷的混合溶液作淋洗液,流速为1．0mL／min时,分离效果良好。7种离子的加标回收率在96％～102％之间,检测下限在0．2～5mg／L之间,方法准确、简便。     

Crystallization of aqueous inorganic-malonic acid particles: nucleation rates, dependence on size, and dependence on the ammonium-to-sulfate ratio

Using an electrodynamic balance, we determined the relative humidity (RH) at which aqueous inorganic-malonic acid particles crystallized, with ammonium sulfate ((NH(4))(2)SO(4)), letovicite ((NH(4))(3)H(SO(4))(2)), or ammonium bisulfate (NH(4)HSO(4)) as the inorganic component. The results for (NH(4))(2)SO(4)-malonic acid particles and (NH(4))(3)H(SO(4))(2)-malonic acid particles show that malonic acid decreases the crystallization RH of the inorganic particles by less than 7% RH when the dry malonic acid mole fraction is less than 0.25. At a dry malonic acid mole fraction of about 0.5, the presence of malonic acid can decrease the crystallization RH of the inorganic particles by up to 35% RH. For the NH(4)HSO(4)-malonic acid particles, the presence of malonic acid does not significantly modify the crystallization RH of the inorganic particles for the entire range of dry malonic acid mole fractions studied; in all cases, either the particles did not crystallize or the crystallization RH was close to 0% RH. Size dependent measurements show that the crystallization RH of aqueous (NH(4))(2)SO(4) particles is not a strong function of particle volume. However, for aqueous (NH(4))(2)SO(4)-malonic acid particles (with dry malonic acid mole fraction = 0.36), the crystallization RH is a stronger function of particle volume, with the crystallization RH decreasing by 6 +/- 3% RH when the particle volume decreases by an order of magnitude. To our knowledge, these are the first size dependent measurements of the crystallization RH of atmospherically relevant inorganic-organic particles. These results suggest that for certain organic mole fractions the particle size and observation time need to be considered when extrapolating laboratory crystallization results to atmospheric scenarios. For aqueous (NH(4))(2)SO(4) particles, the homogeneous nucleation rate data are a strong function of RH, but for aqueous (NH(4))(2)SO(4)-malonic acid particles (with dry organic mole fraction = 0.36), the rates are not as dependent on RH. The homogeneous nucleation rates for aqueous (NH(4))(2)SO(4) particles were parametrized using classical nucleation theory, and from this analysis we determined that the interfacial surface tension between the crystalline ammonium sulfate critical nucleus and an aqueous ammonium sulfate solution is between 0.053 and 0.070 J m(-2).     

On the kinetics and energetics of one-electron oxidation of 1,3,5-triazines

One-electron oxidation of 1,3,5-triazines is observed with both excited uranyl ion (*UO2(2+)) and sulfate radical anion (SO4.-) in aqueous solution, but not with Tl2+, indicating that the standard reduction potentials E degree of 1,3,5-triazine radical cations are = 2.3 +/- 0.1 V vs. NHE, consistent with theoretical calculations; this suggests that if triazines inhibit electron transfer during photosynthesis, they would need to act on the reductive part of the electron transport chain.     

Automated determination of orotic acid, uracil and pseudouridine in urine by high-performance liquid chromatography with column switching.

A column-switching high-performance liquid chromatographic method, requiring no sample preparation apart from filtration, is described for quantification of urinary orotic acid, uracil and pseudouridine. The analyses were carried out using a reversed-phase octadecylsilane-bonded column for sample clean-up and a cation-exchange column for separation; 5-20 microliters samples of urine were directly analysed, and more than 100 samples could be analysed consecutively. Each sample required only 30 min. Detection limits of these compounds were 5 pmol. Creatinine-related urinary uracil excretion was lowest in the newborn period (17.3 +/- 14.4 mumol/g of creatinine). A patient with partial ornithine transcarbamylase deficiency and his mother usually excreted a high level of uracil during the period of normal orotic acid excretion and normal serum ammonia level.