Enantioselective determination of acaricide etoxazole in orange pulp,peel, and whole orange by chiral liquid chromatography with tandem mass spectrometry

An efficient enantioselective method for the determination of etoxazole in orange pulp, peel, and whole orange was developed using liquid chromatography with tandem mass spectrometry. The enantioseparation was performed on a Chiralpak AD‐3R column at 30ºC using acetonitrile with 0.1% formic acid solution (80:20, v/v) as the mobile phase in less than 5 min. Quantification was achieved using matrix‐matched standard calibration curves. The overall mean recoveries for two enantiomers from orange pulp and whole orange were 91.0–99.6% and the orange peel was 92.6–103.1%, with relative standard deviations of 0.8–5.4% intraday and 2.0–4.8% interday at 1, 10, and 100 μg/kg levels, and 1.3–5.2% intraday and 3.5–4.3% interday at 5, 50, and 500 μg/kg levels, respectively. The limits of quantification for all enantiomers in three matrices did not exceed 5 μg/kg. Moreover, the absolute configuration of etoxazole enantiomers had been determined by the combination of experimental and predicted electronic circular dichroism spectra, and the first eluted enantiomer was confirmed as (S)‐etoxazole on a Chiralpak AD‐3R column while (R)‐etoxazole was first on three cellulose chiral columns. The application of the proposed method to real sample analysis suggests its potential use in enantioselective determination of etoxazole enantiomers in citrus.     

Numerical study of laser-induced inelastic collisions in Cs-Sr

Two LICET transitions in Cs-Sr systems are suggested and the results of numerical calculations of the transition probability and collisional crosssection are obtained respectively from our four-level model and the conventional three-level model. Comparisons of these results prove the theoretical prediction that if the frequency difference |ω21| is comparable to |ω43|, the three-level theory has great error in describing the LICET transition, while the four-level theory can describe all cases of LICET process perfectly.     

新型五甲川吡喃鎓盐染料的合成及锁模性能

合成了６ 种五甲川吡喃鎓盐染料，通过红外光谱、核磁共振氢谱及元素分析确证了其结构． 研究了其电子吸收光谱及其在Ｎｄ３ ＋ ：ＹＡＧ激光器上的锁模性能． 结果表明，染料在１ ，２二氯乙烷溶液里最大吸收波长在１０５２ ～１０９５ ｎｍ 之间，６ 个染料全部锁模成功，脉宽为２８ ～３５ ｐｓ，锁模情况比镍络硫代双烯型染料ＢＤＮ 好．     

钾双原子分子21∑＋u─x1∑＋g跃迁连续谱带研究

理论计算了钾双原子分子２１∑＋ｕ─ｘ１∑＋ｇ跃迁所得到的扩散带荧光谱，并与Ｇｏｎｄａｌ等［４］和Ｌｕｈ等［５］以及Ｍｉｌｏｓｅｖｉｃ等［６］的实验结果进行了比较。计算结果与Ｌｕｈ等和Ｍｉｌｏｓｅｖｉｃ等的实验结果符合很好，排除了６００ｎｍ附近扩散带来自Ｋ２２１∑＋ｕ─ｘ１∑＋ｇ跃迁的可能性。     

XeCl激光泵浦S2分子获得紫外激光振荡

本文报道利用ＸｅＣｌ准分子激光（３０８．１ｎｍ）横向泵浦硫双原子分子激光器，在近紫外谱区（３３０．９～３９０．０ｎｍ）的六条谱带上获得激光振荡。计算并测量了Ｓ２分子的吸收系数及小信号增益系数，从而确定了最佳泵浦波长。     

Emission spectra and stimulated emission characteristics of [N<Subscript>2</Subscript>]<Subscript>2</Subscript>−N<Subscript>2</Subscript> molecular dimer

It has been proved byab initio calculation and theoretical analysis that there exist [N₂]₂−N₂ molecular dimers with D_2h symmetry group, and there also exists an electric dipole excimer-like transition a¹B_2g→a¹B_3u. The theoretical spectra accord with the experimental results for transition a¹B_2g→a¹B_3u. The stimulated emission characteristic of N₂ molecular dimer was researched through the microwave excited highly pure nitrogen and the method of amplified spontaneous emission. The experimental results show that N₂ molecular dimer has stimulated emission characteristics when the microwave power is more than 100 W and the N₂ pressure is in the range from 260 Pa to 2200 Pa.     

UR90环形非稳腔输出模式特性的数值分析

将ＵＲ９０环形非稳腔引入氧碘化学激光器，对其输出模式进行了数值模拟计算，模拟包括了化学动力学，介质横向流动和物理光学等因素，得到与放大率Ｍ和光轴离截取镜距离ａ等参数相关的近场光强，位相及远场光强分布曲线。     

HCl＋Xe掺杂CO矩阵晶体中Xe＋2Cl－电子态跃迁

报道ＨＣｌ＋Ｘｅ掺杂ＣＯ矩阵晶体中，在３０８ｎｍ激光的激发下，首次观测到准分子Ｘｅ＋２Ｃｌ－的特征辐射荧光谱。双光子诱导电荷转移合作吸收反应：Ｘｅ＋ＨＣｌ＋２ｈν→αＸｅ＋（ＨＣｌ）－中，双光子吸收截面大于５×１０－４２ｃｍ４ｓ［６］。     

双（1,2—二芳基—1,2—二硫代乙烯）镍配合物合成及光稳定作用

合成了通式为Ｎｉ（ＲＣＳＣＳＲ’）２的６个配合物，这些配合物可由对称或不对称安息香中间体制得。讨论了它们对多甲川菁染料ＨＩＴＣＩ的光稳定作用，发现含镍配合物的染料溶液光退色速度低于不含镍梧合物浓工。     

Tablet‐effervescence‐assisted dissolved carbon flotation for the extraction of four triazole fungicides in water by gas chromatography with mass spectrometry

A pretreatment method named tablet‐effervescence‐assisted dissolved carbon flotation was introduced for the determination of four triazole fungicides in environmental water. In this method, the use of effervescent tablet composed of nontoxic sodium carbonate and sodium dihydrogen phosphate could generate CO₂ in situ to assist the dispersion of extraction solvent and to accelerate mass transfer of target analytes. In addition, the simple phase separation simply based on the rising of low‐density organic solvent from the aqueous phase was applied rather than the application of apparatus, which demonstrated the potential for on‐site extraction in the field. The experimental variables, including the composition of effervescent tablets, amount of effervescent tablets, types and volume of extraction solvent, were investigated. Under the optimized conditions, the method showed good linearity for myclobutanil, tebuconazole, epoxiconazole, and difenoconazole in the range of 1–100 μg/L. The limits of detection and the limits of quantification were within the range of 0.15–0.26 and 0.49–0.86 μg/L, respectively. The obtained correlation coefficients varied from 0.997 to 0.999, and suitable enrichment factors were 422–589. The recoveries were 82.5–112.9% with relative standard deviations of 4.7–13.5%.