三波长K系数分光光度法同时测定痕量磷,砷,硅

１引言以碱性染料光度法同时测定磷、砷、硅已有报道，但需加入掩蔽剂或经还原－萃取等分离。本文用三波长Ｋ系数法原理，由计算机选出最佳波长组合，不经分离、掩蔽，于一份试液中同时测定痕量磷、砷、硅，其线性范围分别为４０．０～２４０．０μｇ／Ｌ、３２．０～１２０．０μｇ／Ｌ、３２．０～３２０．０μｄ／Ｌ。用于合成样品测定，结果令人满意。２实验部分２．１仪器与试剂７２２型光栅分光光度计。硅标准溶液：用高纯ＳｉＯ２（９９．９９％）以常法熔融配成ｐＨ约１．５的溶液，含硅０．１００ｇ／Ｌ；磷标准溶液：用ＫＨ２ＰＯ…     

Uniconazole—P的合成

对氯苯甲醛与α－三唑基频哪酮在ＫＦ／Ａｌ２Ｏ３／ＰＥＧ４０００存在下经Ｋｎｏｅｖｅｎａｇｅｌ反应得８５％烯基三唑酮（Ⅱ）（Ｅ／Ｚ＝０．６５），Ⅱ经光异构化得９２％Ｅ－Ⅱ（Ｅ／Ｚ≥９９／１）；Ｅ－Ⅱ在手性相转移催化剂的存在下进行选择性不对称还原得９２％Ｕｎｉｃｏｎａｚｏｌｅ－Ｐ（Ⅰ），ｅｅ＝３０％，Ｅ／Ｚ≥９９／１．Ⅰ是高效的植物生长延缓剂．     

黄金饰品中金含量的X－荧光能谱分析

应用Ｘ－荧光能谱分析（ＥＤ－ＸＲＦ）和新的定量分析软件测定了２６个黄金标样，研究了饰品形状的影响，不同方法，不同实验室测试结果的比对，表明在所选的工作条件下样品形状无明显影响。方法可靠、快速、简便，非破坏性，适于常规、批量分析。Ａｕ含量≥９９％时，分析误差≤０．１５％，精密度≤０．１％；金含量９０％～９９％时，分析误差和精密度≤０．２％；金含量７５％～９０％和＜７５％时，分析误差分别≤０．４％和０．５％，精密度均≤０．２％；Ａｇ、Ｃｕ和Ｚｎ的分析误差均≤０．５％，精密度≤０．２％。少标样基本参数法和多标样回归法的结果一致，在实用上有重要意义，十分有利于ＥＤ－ＸＲＦ的推广应用。     

核级银铟镉合金中Ag In Cd 的连续滴定

研究了测定核级银铟镉合金中Ａｇ、Ｉｎ、Ｃｄ的连续滴定法。以电位滴定法测定Ａｇ；在ｐＨ２．５以ＥＤＴＡ滴定Ｉｎ；在ｐＨ≥５．５以ＥＤＴＡ滴定Ｃｄ，当ｎ＝１１时，其ＲＳＤ分别为：Ａｇ０．１１％、Ｉｎ０．５２％、Ｃｄ１．１％，合成试样分析回收率分别为：Ａｇ９９．８％～１００．１％、Ｉｎ９９．６％～１００．３％、Ｃｏ９７．６％～１０１．３％，测定９２个合金试样，其Ａｇ，Ｉｎ，Ｃｄ合量范围为：９９．７８％～     

气相色谱法用于樟脑酚液的定量研究

建立了樟脑酚液中的樟脑，苯酚的气相色谱定量法。樟脑的平均回收率为９９．８９％，ＲＳＤ＝０．７１；苯酚的平均回收率为１００．１％，ＲＳＤ＝０．６１％。     

病人血样中痕量锗,锶的石墨炉原子吸收光谱法测定

本文运用石墨炉ＡＡＳ法加基体改进技术，测定了５０岁以上病人血清及环境水样中锗和锶的含量。用０．０１ｍｏｌ／ＬＨＮＯ３－０．１％ＴｒｉｔｏｎＸ－１００稀释血清，测定精度可与火焰法媲美。锗，锶的特征量分别为２８ｐｇ和１８ｐｇ；线性范围为０－２５０ｎｇ／ｍＬ和－３５．０ｎｇ／ｍＬ；相对标准偏差（ｎ＝１０）４．１０％和２．４９％；回收率分别为９２．２％－９９．０％和９２．０％１０２％。方法快速准确，结果满     

ICPMS测定高纯氧化钇中痕量稀土杂质的研究

研究了直接电感耦合等离子质谱（ＩＣＰＭＳ）测定９９．９９９％纯度氧化钇中稀土杂质的方法，详细探讨了仪器工作参数对稀土元素的测定的影响，对各种干扰现象进行了研究，并提出定量校正方法，实验表明，加入内标元素可有效地克服基体效应、接口效应和仪器工作参数漂移的影响。方法的检出限为０．００３～０．０２ｎｇ／ｍｌ，变异系数（ＣＶ％）为０．２％～５．４％，回收率为９０％～１１５％。适合９９．０％～９９．９９９％     

ICP—AES直接测定荧光级氧化铕中5个稀土杂质

本文采用Ｊｏｂｉｎ Ｙｖｏｎ ３８Ⅱ谱仪直接测定高纯氧化铕中Ｃｓ，Ｐｒ，Ｓｍ，Ｇａ，Ｄｙ５个稀土杂质，试验考查了氧化铕基体，共存元素，酸度等因素的影响。利用正交试验Ｌ２５（５）＾６确定了仪器最佳条件。当基体纯度为９９．９９％时；回收率在９４．０～１０８．０％之间。在实际应用中获得满意的结果。     

示波极谱同时测定金属锌中铅和镉

本文提出了在ＨＣｌ－Ｈ＿３ＰＯ＿４－ＫＣｌ底液中示波极谱同时测定金属锌中铅、镉含量的方法，检测下限铅为０．１ｍｇ／Ｌ，镉为０．０１ｍｇ／Ｌ铅、锡波形清晰，重视性好。试样中加标准回收，铅回收率为９９．２％～１００％，镉回收率为９５％～９８％，与标准方法比较，相对误差＜５％。方法准确、简便、快速，适用于金属锌中铅、镉的常规分析。     

示波极谱同时测定金属锌中铜和镉

本文提出了在ＨＣｌ－Ｈ３ＰＯ４－ＫＣｌ底液中示波极谱同时测定金属锌中铅，镉含量的方法，检测下限铅为０．１ｍｇ／Ｌ，镉为０．０１ｍｇ／Ｌ，铅、锡波形清晰，重现性好，试样中回标准回收，铅回收率为９９．２％～１００％，镉回收率为９５％～９８％，与标准方法比较，相对误差〈５％，方法准确，简便，快速，适用于金属锌中铅，镉的常规分析。     

Separation of Biphenyl Nitrile Compounds by Microemulsion Electrokinetic Chromatography with Mixed Surfactants

A mixture of nine biphenyl nitrile compounds with high hydrophobicity and similar structures was successfully separated by microemulsion electrokinetic chromatography (MEEKC) within 30 rain. The buffer system contained 100 mmol/L sodium dodecyl sulfate (SDS), 80 mlnol/L sodium cholate (SC), 0.81% heptane, 7.5% n-butanol, 10% acetonitrile and 10 mmol/L borate. The addition of SC, organic modifiers, sample preparation and temperature all showedremarkable effect on the separation. Meanwhile, the MEEKC method was briefly compared with micellar electrokinetic chromatography (MEKC) method.     

离子色谱法测定“地沟油”中钠离子和氯离子的含量及其比例关系

采用离子色谱法测定“地沟油”样品中钠离子和氯离子的含量,通过计算两者的比例关系确定样品中是否含有“地沟油”。使用去离子水提取“地沟油”样品中钠离子和氯离子。氯离子以20 nmol/L KOH溶液为淋洗液,AS19分离柱(250 mm×4 mm)分离,抑制器电流112 mA;钠离子以20 nmol/L甲基磺酸(MSA)为淋洗液,CS12分离柱(250 mm×4 mm)分离,抑制器电流59 mA;两者分离采用的其他相同色谱条件为: 柱温、检测器温度30 ℃,电导检测器检测,进样量25 μL,流量1 mL/min,峰面积定量。氯离子的检出限为0.005 mg/L,在0～5 mg/L范围内有良好的线性关系（r2=0.999988）;钠离子的检出限为0.001 mg/L,在0～5 mg/L范围内有良好的线性关系（r2=0.999926）。氯离子平均加标回收率为94.2%,相对标准偏差(RSD)为2.4%;钠离子平均加标回收率为92.5%, RSD为2.7%。经测定、计算,正常食用油中钠离子和氯离子的物质的量比约为1,而“地沟油”中钠离子与氯离子的物质的量比高于4。“地沟油”中钠离子和氯离子的含量及其比例关系可作为判断“地沟油”的重要依据。     

Rapid assessment of beta-asarone content of Acorus calamus by micellar electrokinetic capillary chromatography

This report outlines a rapid, reproducible method for the determination of beta-asarone, a known carcinogen, using micellar electrokinetic capillary chromatography (MEKC)-UV-vis absorbance and a simple alcohol extraction. The MEKC method is based on a running buffer comprised of 100 mM sodium dodecyl sulfate (SDS), pH 10. The method is reproducible and provides baseline separation of alpha-asarone and beta-asarone. This protocol was used to determine the beta-asarone content of Acorus calamus rhizome of a diploid variety harvested from the wetlands of the United States and the triploid variety from India obtained commercially. The results indicate raw product that originated from India contained 4.4% w/w beta-asarone, while that from the United States contained 0.2% w/w beta-asarone. Neither sample contained detectable concentrations of alpha-asarone. This is the first report of the use of MEKC to determine asarone in a natural source.     

The Effects of Surfactants on the Estimation of Bacterial Density in Petroleum Samples

The effect of the surfactants polyoxyethylene monostearate (Tween 60), polyoxyethylene monooleate (Tween 80), cetyl trimethyl ammonium bromide (CTAB), and sodium dodecyl sulfate (SDS) on the estimation of bacterial density (sulfate-reducing bacteria [SRB] and general anaerobic bacteria [GAnB]) was examined in petroleum samples. Three different compositions of oil and water were selected to be representative of the real samples. The first one contained a high content of oil, the second one contained a medium content of oil, and the last one contained a low content of oil. The most probable number (MPN) was used to estimate the bacterial density. The results showed that the addition of surfactants did not improve the SRB quantification for the high or medium oil content in the petroleum samples. On other hand, Tween 60 and Tween 80 promoted a significant increase on the GAnB quantification at 0.01% or 0.03% m/v concentrations, respectively. CTAB increased SRB and GAnB estimation for the sample with a low oil content at 0.00005% and 0.0001% m/v, respectively.     

Effect of wet spinning parameters on the properties of novel cellulosic fibres

Novel cellulose fibres (Biocelsol) were spun by traditional wet spinning technique from the alkaline solution prepared by dissolving enzyme treated pulp directly into aqueous sodium zincate (ZnO/NaOH). The spinning dope contained 6 wt.% of cellulose, 7.8 wt.% of sodium hydroxide (NaOH) and 0.84 wt.% of zinc oxide (ZnO). The fibres were spun into 5% and 15% sulphuric acid (H₂SO₄) baths containing 10% sodium sulphate (Na₂SO₄). The highest fibre tenacity obtained was 1.8 cNdtex⁻¹ with elongation of 15% and titre of 1.4 dtex. Average molecular weights and shape of molecular weight distribution curves of the celluloses from the novel wet spun cellulosic fibre and from the commercial viscose fibre were close to each other.     

Sweeteners determination in table top formulations using FT-Raman spectrometry and chemometric analysis

A partial least squares (PLS) Fourier transform Raman spectrometry procedure based on the measurement of solid samples contained inside standard glass vials, has been developed for direct and reagent-free determination of sodium saccharin and sodium cyclamate in table top sweeteners. A classical 2² design for standards was used for calibration, but this system provides accuracy errors higher than 13% w/w for the analysis of samples containing glucose monohydrate. So, an extended model incorporating glucose monohydrate (2³ standards) was assayed for the determination of sodium saccharin and sodium cyclamate in all the samples. Mean centering spectra data pre-treatment has been employed to eliminate common spectral information and root mean square error of calibration (RMSEC) of 0.0064 and 0.0596 was obtained for sodium saccharin and sodium cyclamate, respectively. A mean accuracy error of the order of 1.1 and 1.9% w/w was achieved for sodium saccharin and sodium cyclamate, in the validation of the method using actual table top samples, being lower than those obtained using an external monoparametric calibration. FT-Raman provides a fast alternative to the chromatographic method for the determination of the sweeteners with a three times higher sampling throughput than that obtained in HPLC. On the other hand, FT-Raman offers an environmentally friendly methodology which eliminates the use of solvents. Furthermore, the stability of samples and standards into chromatographic standard glass vials allows their storage for future analysis thus avoiding completely the waste generation.     

Rapid mass-spectrometric determination of boron isotopic distribution in boron carbide

Boron isotopic ratios are measured in boron carbide by thermionic ionization mass spectrometry with no prior chemical separation. A powder blend of boron carbide and sodium hydroxide is prepared, a small portion is transferred to a tantalum filament, the filament is heated to produce sodium borate, and the filament is transferred to the mass spectrometer where the(11)B/(10)B ratio is measured, using the Na(2)BO(2)(+) ion. Variables investigated for their effect on preferential volatilization of (10)B include the sodium hydroxide-boron carbide ratio and the temperature and duration of filament heating. A series of boron carbide pellets containing natural boron, of the type proposed for the control rods of the Fast Flux Test Facility reactor, were analysed with an apparently unbiased result of 4.0560 for the (11)B/(10)B ratio (standard deviation 0.0087). The pellets contained over 3% metal impurities typically found in this material. Time of analysis is 45 min per sample, with one analyst.     

Detection and Analysis of Methyltins in Extracts from Mouse Tissues Following Injection of Trimethyltin

Abstract

An internal standard method is described for the extraction and quantification of methyltins from mouse tissues with picogram sensitivity. Mice of four different inbred strains received single I.P. injections of trimethyltin (2.3 mg/kg in physiological saline). Four days after injection, tissues were taken for extraction and quantification of methyltins. Tissues were extracted with 0.2% tropolone in hexane and HCl, dried over sodium sulfate, adsorbed through florisil and sodium sulfate, derivatized with pentylmagnesium bromide and analyzed on a gas chromatograph with flame photometric detection. Trimethyltin was the only form of tin found in most of the tissue samples analyzed. Approximately one fifth of the tissue samples contained small amounts (up to 6.4% of total tin present) of dimethyltin. None of the tissue samples contained monomethyltin. There were no strain differences in the amounts of trimethyltin or dimethyltin found in the tissues. We conclude that trimethyltin is not metabolized to any significant extent in the mouse strains tested. The method described should be useful for the extraction and analysis of methyltins from a variety of sources such as sediments, excreta, and tissues.     

Separation of rutin nona(H-) and deca(H-) sulfonate sodium by ion-pairing reversed-phase liquid chromatography

Ion-pairing reversed-phase liquid chromatography (RPLC) was used to separate two polysulfonates, rutin nona(H-) sulfonate sodium and rutin deca(H-) sulfonate sodium, which have very similar chemical structures. The final product always contained both of them when one of the compounds was synthesized. Baseline separation was achieved on a C8-bonded silica column at ambient temperature. The eluent was acetonitrile-15 mM phosphate buffer solution containing 20 mM TBA (pH 6.0) (46:54, v/v). The calibration plot was linear in the concentration range 0.5-200 microg ml(-1) for both analytes. The limits of detection (LODs; 254 nm) were 0.03 microg ml(1-) for rutin nona(H-) sulfonate sodium and 0.04 microg ml(-1) for rutin deca(H-) sulfonate sodium. Three batches of rutin deca(H-) sulfonate sodium were analyzed using the assay; the results showed that the analytical performance is really satisfactory.     

Separation and determination of biphenyl nitrile compounds by microemulsion electrokinetic chromatography with mixed surfactants

A mixture of six biphenyl nitrile compounds and three related substances with high hydrophobicity and similar structures was successfully separated by microemulsion electrokinetic chromatography (MEEKC) within 30 min. The microemulsion system contained 100 mM sodium dodecyl sulfate (SDS), 80 mM sodium cholate (SC), 0.81% v/v heptane, 7.5% v/v n-butanol, 10% v/v acetonitrile, and 10 mM borate. The addition of SC, organic modifiers, sample preparation, and temperature all showed remarkable effects on the separation. The capacity factor (k) was calculated by using dodecyl benzene as the marker for microemulsion, and the calculated partition coefficient log P(o/w) of the solutes was in the range of 3.35-7.38. The log k values matched well with the log P(o/w) with a correlation coefficient of 0.96. In addition, the linear correlation coefficients of each compound between peak area and concentration were from 0.996 to 0.998 with the repeatability RSD value < 1.2% for migration time and < 4.8% for peak area, and the highest theoretic plate number was > 586000. MEEKC was compared with micellar electrokinetic chromatography (MEKC) indicating that the former method is more suitable for this separation and can be used for the quality control of biphenyl nitrile compounds in the synthesis of liquid crystals.