用离子色谱法同时测定茶叶中的F-、Cl-、SO24- No3-

利用美国戴安公司免试剂离子色谱系统(ICS-2000系统),采用KOH梯度离子色谱法和抑制电导检测器,建立了同时测定茶叶中F-、Cl-、SO24-、NO3等四种重要的阴离子的分析方法.研究了茶叶中F-、Cl-、SO24-、NO3四种阴离子的色谱分析条件,建立了8-44-52-8mmol/L的KOH梯度淋洗程序,流速为1.0ml/min.结果表明:该方法回归方程的线性相关系数达到0.9999以上,各组分的检出限在0.01～0.05mg/L之间,回收率在88.6%～107.5%之间.用本方法用于实际茶叶样品中F-、Cl-、SO24-、NO3等无机酸阴离子的分析,简便、实用,并且快速、准确,所得结果令人满意.     

离子色谱法测定碳酸盐及磷酸盐中四种无机阴离子

建立离子色谱等度分离测定碳酸盐及磷酸盐中F－、Cl－、SO42－、NO3－ 4 种无机阴离子的方法,碳酸盐试样用20 mmol/L氢氧化钠溶液溶解,加磷酸中和至pH 4.5～5.5;磷酸盐试样直接用20 mmol/L氢氧化钠溶液溶解。色谱柱采用AS11-HC分离柱,流动相20 mmol/L氢氧化钠溶液,流速1.0 mL/min。结果表明：F－、Cl－、SO42－、NO3－4 种阴离子质量浓度与峰面积呈良好线性关系（r = 0.999 2～0.999 9）,检出限分别为2.0、2.0、2.5、2.5 mg/kg,在低、中、高3 个加标水平下的平均回收率为80%～109.88%,相对标准偏差为0.85%～4.67%（n=6）。该方法准确、简便、灵敏、通用、重复性好,可用于碳酸盐及磷酸盐中4 种阴离子的实际检测。     

离子色谱法测定中草药成分的研究

建立并优化了高效、简便的阴离子交换色谱分析中草药中的无机阴离子、有机酸和糖类化合物的方法.采用METROSEP A Supp 4-250分离柱,1.8mmol/L Na2CO3+1.7mmol/L NaHCO3+2%丙酮淋洗液,电导抑制检测,分离测定F-、C1-、Br-、NO2-、NO3-、PO34-、SO24-和草酸、苹果酸和富马酸等无机阴离子和有机酸.采用METROSEP CARB 1(150×4.0mm)分离柱,10.0mmoL/L NaOH淋洗液,脉冲安培检测,分离测定阿拉伯糖、半乳糖、葡萄糖、甘露糖和果糖等糖类化合物.方法快速、有效地分析了中草药的成分,结果令人满意.     

离子色谱法测定饮用水中的8种阴离子

利用MIC型离子色谱仪,对饮用水中F^-、Cl^-、NO2^-、NO3^-、P04^3-和SO4^2-阴离子进行检测。采用Supp5-4．0mm＊150mm离子色谱柱,3．2mol/L碳酸钠和1．0mol／L碳酸氢钠淋洗液,抑制型电导检测。结果表明,利用这个离子色谱的最佳条件可以对饮用水中的8种阴离子同时准确快速地定性定量检测。F^-、HCOO^-、Cl^-、NO2^-、Br^-、NO3^-、PO4^3-和SO4^2-的相对标准偏差为：1．588％-3．270％,检出限为：0．012mg／L-5．076mg／L,回收率为：94．0％～105．2％。实验结果发现有水样中的F含量超出国家标准。     

紫外检测离子色谱法测定酱腌菜中的亚硝酸盐与硝酸盐

建立了紫外检测离子色谱法测定酱腌菜中的亚硝酸盐与硝酸盐的分析方法。样品经超声提取后,以1.8 mmol/L Na2CO3+1.7 mmol/L NaHCO3为流动相,经Metrosep A Supp 4-250阴离子交换色谱柱分离,于210nm处紫外检测。结果表明:此法NO2-、NO3-的检出限分别为1.0 mg/kg和2.0 mg/kg,实际样品的加标回收率分别为80.4%~82.1%和93.1%~96.5%,相对标准偏差≤10%。     

离子色谱法测定高纯氯化锂中的五种微量阴离子

研究了氧化银沉淀法排除Cl-的干扰,离子色谱法测定氯化锂中NO-3、SO2-4、F-、NO-2、PO3-4的方法.采用美国Dionex公司产ICS-90型离子色谱仪,分离柱为IonPac AS14阴离子分离柱,以3.5×10-3mol/L Na2CO3和1.0×10-3mol/L NaHCO3作为淋洗液,流速为1.2mL/min,测定了氯化锂中杂质阴离子的含量.相对标准偏差(RSD)为0.2440%～1.3253%,样品回收率为94.56%～103.05%.该方法简便、快速、准确可靠.     

离子色谱法测定食品添加剂磷酸二氢钙中的阴离子

目的 建立一种同时测定磷酸二氢钙中的F-、Cl-、SO42-、NO3-4种阴离子的分析方法.方法 以碳酸钠和氢氧化钠溶液为淋洗液,通过对淋洗液等色谱分析条件的优化,选择离子色谱法测定食品添加剂CaH2PO4中的阴离子,以标准物质保留时间定性,以外标法定量.结果 在优化的色谱条件下,4种离子的分离度好,检测灵敏度高;被测离子的浓度在一定范围内与色谱峰面积呈良好的线性关系,相关系数r＞0.999.4种离子测定结果相对标准偏差均＜3％(n=9),平均加标回收率为80％～105％.结论 离子色谱法简便、灵敏、快速,能够满足同时测定CaH2PO4中4种阴离子含量的要求.     

用离子色谱法同时测定茶叶中的F^-、Cl^-、SO4^2-、NO3^-

利用美国戴安公司免试剂离子色谱系统（ICS-2000系统）,采用KOH梯度离子色谱法和抑制电导检测器,建立了同时测定茶叶中F^-、Cl^-、SO4^2-、NO3等四种重要的阴离子的分析方法。研究了茶叶中F^-、Cl^-、SO4^2-、NO3四种阴离子的色谱分析条件,建立了8-44-52-8mmol／L的KOH梯度淋洗程序,流速为1．0ml／min。结果表明：该方法回归方程的线性相关系数达到0．9999以上,各组分的检出限在0．01～0．05mg／L之间,回收率在88．6％～107．5％之间。用本方法用于实际茶叶样品中F^-、Cl^-、SO4^2-、NO3等无机酸阴离子的分析,简便、实用,并且快速、准确,所得结果令人满意。     

离子色谱法测定五大连池矿泉水中无机阴离子

为了研究五大连池矿泉水中无机阴离子含量和组成,采用离子色谱法测定五大连池矿泉水中的F~-、Cl~-、NO_2~-、NO_3~-和SO_4~(2-)五种阴离子的含量。建立能同时测量重碳酸矿泉水和偏硅酸矿泉水中5种阴离子的测试方法。该方法色谱峰分离效果好,标准曲线相关系数在0.999以上,方法检出限在0.011～0.025 mg/L之间,标准偏差在1.03%～3.92%之间(N=15),加标质量浓度在1～3 mg/L之间,加标回收率在97.70%～103.68%之间(N=15)。结果表明,五大连池矿泉水阴离子含量适中,测定的5种阴离子均符合GB 8537—2008的相关规定。     

离子色谱法梯度淋洗测定降水中无机阴离子

采用离子色谱法梯度淋洗技术对降水中的F-,Cl-,NO3-,SO42-4种阴离子分析测定,实验步骤、各参数测试及评价参照《水质无机阴离子的测定离子色谱法》HJ/T84-2001及《离子色谱仪》JJG823-2014。实验结果显示,在离子色谱法梯度淋洗技术模式下,色谱峰间分离效果良好,线性相关系数、检出限、稳定性、准确度等指标都满足相关标准规范分析要求,适用于降水中阴离子的测定。     

海南省水产品中铅镉的污染状况分析

目的 测定海南省东西南北不同城市水产品中铅镉含量,了解水产品中铅镉污染状况并进行分析与评价.方法 用随机抽样的方法,采集鱼类、软体类、甲壳类和双壳类4类238份样品,用石墨妒原子吸收法测定水产品中铅镉含量,根据无公害食品水产品有毒有害物质限量标准等对金属含量进行分析.结果 海南省水产品中铅污染的范围在0.005 ～ 0.717 mg/kg,镉污染范围在0.100×10-3 ～ 0.648 mg/kg,含量低于国内各相关标准的限值,水产品中铅镉污染最高值均为双壳类.结论 海南省水产品铅镉的污染以中国、美国、澳大利亚和韩国的标准判断均处于安全范围内,按照欧盟的标准鱼类中的铅有超标现象,其余均为合格.     

北京市农田回用再生水中无机阴离子的 分布规律研究

目的建立离子色谱法测定北京市农田回用再生水水体中F~-、NO_3~-、NO_2~-、Cl~-、SO_4~(2-)和PO_4~(3-)6种无机阴离子的分析方法。方法分别采集北京某再生水厂出水口、再生水灌溉渠、农田灌溉点的36份水样,经Dionex OnGuard Ⅱ Ag/H银离子交换柱处理后,采用离子色谱法测定,色谱柱为Dionex IonPac~(TM)AS11-HC,检测器为电导检测器。结果该方法能有效分离6种无机阴离子,且在0.016~10 mg/L浓度范围内线性关系良好(r~20.99),相对标准偏差在0.54%~3.65%之间。北京市农田回用再生水中检出了不同浓度水平的6种无机阴离子,其中Cl~-检出浓度最高,浓度范围为121~211 mg/L,不同位点的再生水中的浓度存在空间分布差异,NO_3~-和PO_4~(3-)在再生水出水口的浓度要高于再生水灌溉渠和农田灌溉点。结论本方法稳定性和分离效果好,准确率高,可适用于再生水中6种阴离子的监测。建议加强农田回用再生水的长期监测,并根据作物种类和土壤类型等制定更加严格的农田回用再生水水质标准。     

Effect of Various lons on the Kinetics of Retrogradation of Concentrated Wheat Starch Gels

The effect of various ions on the mode and kinetics of concentrated wheat starch gels retrogradation was investigated. The anions SCN^-, I^-, NO, Br⁻, F⁻ and SO, and the cations K⁺, Li⁺ and Na⁺ were tested at 0,4-M concentration. Teh results, based on the Avrami theory, indicated that the mechanism of starch crystallization is instantaneous nucleation followed by rod-like growth of crystals regardless the ion present. The retrogradation rate for the halogens anions increased in the following order: I⁻, Br⁻, CI⁻ and F⁻. The retrogradation rate for the cations increased in the following order: K⁺, Li⁺ and Na⁺. The results obtained were dependent of the charge distribution of the anions studied.     

The Correlation of Inorganic Anion Contents in Rice and Its Soils Based on Four Geographical Origin

The determination of the geographical origin of foodstuffs is becoming of increasing interest to consumers and producers since it may be used as a criterion to certify quality and typicality. The correlation of inorganic anion contents in rice and its origin soils was studied in this paper, and the inorganic anion contents were used to identification the rice geographical origin. The contents of F^?, Cl^?, NO₂ ^?, NO₃ ^?, and SO₄ ^2? in rice samples and soil samples from four provinces of China were analyzed by ion chromatography. The result of variance analysis and correlation analysis demonstrated that there is significant difference in the contents for F^?, Cl^?, NO₂ ^?, NO₃ ^?, and SO₄ ^2? in the rice samples from four provinces, and the anions in rice are closely connected with the anions in soil. The predictions of geographic origin made by linear discriminant analysis (LDA) based on anions gave an overall correct classification rate of 100 % and cross-validation rate of 96.9 %. The correct rate of Q-type hierarchical cluster analysis (Q-type CA) was 81.3 %. These results demonstrate the usefulness of multi-anion fingerprints as indicators for authenticating the geographical origin of the four famous brand rices.     

Aluminium and Its Complexes in Teas and Fruity Brew Samples,Speciation and Ions Determination by Ion Chromatography and High-Performance Liquid Chromatography–Fluorescence Analytical Methods

The paper presents results of aluminium determination in samples of black and fruit teas. Total aluminium concentration was determined along with the concentration of aluminium in a cup of tea in tea samples in two price groups (>1€ and <1€). Based on the conducted study, no differences were found in aluminium concentration in black and fruit teas depending on the price group. Developed ion chromatography method was applied to determine inorganic and organic ions in tea samples, especially those which may form complexes with aluminium: fluoride, sulphate, oxalate and citrate ions. Analysis by this method using ion chromatography allowed for the determination of 12 anions: F^?, HCOO^?, CH₃COO^?, NO₂ ^?, Br^?, NO₃ ^?; Cl^?, CH₂(COO)₂ ^2?, SO₄ ^2?, C₂O₄ ^2?, PO₄ ^3? and C₃H₅O(COO)₃ ^3? in the time of 40 min. Speciation analysis of aluminium was performed in optimised HPLC-fluorescence analytical system (with Lumogallion as a post-column reagent). It was observed that organic aluminium complexes are quickly degraded to form Al³⁺ which is the reason why speciation analysis in tea samples does not provide the full image of speciation distribution. Nevertheless, this developed method was successfully used in the determination of aluminium complexes with fluorides in tea samples.     

水产品中二氧化硫残留量的调查分析

目的了解我国市售水产品中二氧化硫(sulfur dioxide,SO_2)的残留状况,为制定和完善水产品中SO_2限量标准提供科学依据。方法根据GB/T5009.34-2016《食品安全国家标准食品中二氧化硫的测定》中的检测方法,对山东、浙江、天津2014~2016年市售的虾蟹类及其制品101例、鱼类及其制品95例、贝类及其制品42例和头足类及其制品29例共267例样品进行SO_2残留检测。结果水产品及其制品中SO_2的残留量范围为ND~3994.38 mg/kg,平均残留量达到57.10 mg/kg,多数处于较低水平。不同种类的水产品及其制品中SO_2的残留量差异有统计学意义(P0.05),其中虾蟹类及其制品中的SO_2的残留量明显高于其他水产品,其残留量平均值达到130.93 mg/kg,其中最大值为3994.38 mg/kg。结论 SO_2在不同种类的水产品中均有不同程度的存在,水产品中SO_2残留问题亟需关注。     

Solution chemistry effects on orthophosphate adsorption by cationized solid wood residues

Adsorption of orthophosphate anions in aqueous solution by cationized milled solid wood residues was characterized as a function of sorbate-to-sorbent ratio (approximately equal to 0.001-2.58 mmol of P/g substrate), pH (3-9), ionic strength, I (no I control; 0.001 and 0.01 M NaCl), reaction time (4 min to 24 h), and in the presence of other competing anions (0.08-50 mM SO4(2-); 0.08-250 mM NO3-). Sorption isotherms revealed the presence of two kinds of adsorption sites corresponding to high and low binding affinities for orthophosphate anions. Consequently, a two-site Langmuir equation was needed to adequately describe the data over a range of solution conditions. In addition to higher sorption capacity, cationized bark possessed a higher binding energy for orthophosphate anions compared to cationized wood. The sorption capacity and binding energy for bark were 0.47 mmol of P g(-1) and 295.7 L mmol(-1), respectively, and for wood, the corresponding values were 0.27 mmol g(-1) and 61.4 L mmol(-1). Both the sorption capacity and binding energy decreased with increasing I, due to competition from Cl- ions for the available anion-exchange sites. The surface charge characteristics of cationized bark (pHzpc = 7.9) acted in concert with orthophosphate speciation to create a pH-dependent sorption behavior. Orthophosphate uptake was quite rapid and attained equilibrium levels after 3 h. Both SO4(2-) and NO3- influenced percent removal but required high relative competing anion to H2PO4- molar ratios, i.e., 2.5-3 for SO4(2-) and 25 for NO3-, to cause appreciable reduction. These results support our hypothesis that adsorption of orthophosphate anions on cationized bark involves ion exchange and other specific Lewis acid-base interactions.     

Ion-exchange chromatographic analysis of soluble cations,anions and sugars in milk whey

Three ion-exchange chromatography methods for the separation and quantification of soluble compounds, including cations, anions and carbohydrates in liquid whey were developed. While cations and anions were successfully separated by ion chromatography coupled with electrochemical suppressed conductivity detection, carbohydrate analysis was accomplished by high-pH anion exchange chromatography in conjunction with pulsed amperometric detection. All separations were performed under isocratic elution conditions. With a simple sample preparation, these methods enabled interference-free identification and sensitive quantification of whey soluble ions and compounds: Na⁺, NH₄⁺, K⁺, Mg²⁺ and Ca²⁺, Cl^-, SO₄^2-, PO₄^3-, citrate, isocitrate, and lactose along with some minor sugars, such as galactose, glucose, and N-acetylgalactosamine. Whereas no significant differences were observed between the mean concentrations of Na⁺, K⁺ and Mg²⁺ in wheys deriving from bovine milk of different cheesemaking technologies, the free Ca²⁺ content in hard cheeses was less than a half of that found in whey from soft cheeses (560ᆞ mg/l, n=4) as a result of a more favoured solubilization of calcium from the colloidal phase. In spite of an elevated amount of lactose, separation and quantification of minor whey sugars was possible.     

ION LEVELS OF FRESH AND PROCESSED SPINACH USING ION CHROMATOGRAPHY

The anion (Cl^?, NO^?₃, So^2-₄, PO^3-₄, OX^2-) and cation (Na⁺, K⁺, NH4⁺) composition of raw, frozen and canned spinach samples was determined by Ion Chromatography (IC). In general, the levels of these ions were determined after typical food processing operations. Important for its health-related and nutritional point of view is the observation that nitrate levels decreased by about 50% with losses of 15% in total organic nitrogen after typical commercial processing methods.