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1.
建立了气相色谱-串联质谱(GC-MS/MS)同时测定豆芽和番茄中4-氯苯氧乙酸、2,4-二氯苯氧乙酸、萘乙酸、吲哚乙酸、2,4-二氯苯氧乙酸丁酯、吲哚丁酸6种植物生长调节剂残留量的分析方法。试样经酸性乙腈提取,盐析、离心、浓缩、复溶,经三氟化硼甲醇溶液甲酯化,再加入2,4-二氯苯氧乙酸丁酯的溶解液,经过液液萃取后,通过气相色谱-串联质谱仪进行检测,外标法定量。方法的定量下限(S/N10)均为15μg/kg;在豆芽、番茄中分别添加15,30,60μg/kg 3个浓度水平的植物生长调节剂,其回收率为70.0%~127%,相对标准偏差(n=6)为4.1%~11.4%。该方法的定量下限满足目前国内外有关法规对豆芽和番茄中植物生长调节剂的最大残留限量要求,可为进出口豆芽和番茄中植物生长调节剂残留的监管提供技术支持。  相似文献   
2.
In this study, a new two–step extraction procedure based on the combination of a modified quick, easy, cheap, effective, rugged, and safe extraction method with a deep eutectic solvent based microwave‐assisted dispersive liquid–liquid microextraction has been developed for the extraction of multiclass pesticides in tomato samples before their analysis by gas chromatography with flame ionization detection. In this method, initially, an aliquot of tomato is crushed and diluted with deionized water. The mixture is then passed through a filter paper and its residue and aqueous phase are separated. Afterwards, acetonitrile as an extraction/disperser solvent is passed through the filter paper containing the refuse. The analytes remained in the refuse are extracted into the acetonitrile and then the obtained extract is mixed with a deep eutectic solvent. The obtained mixture is injected into the tomato juice and placed in a microwave oven for 15 s. Consequently, a cloudy state is formed and the extractant containing the analytes are sedimented at the bottom of the tube after centrifugation. Finally, 1 μL of the sedimented phase is removed and injected into the separation system. Under the optimum conditions, limits of detection and quantification were in the ranges of 0.42–0.74 and 1.4–2.5 ng/g, respectively.  相似文献   
3.
In this work, a novel quick, easy, cheap, effective, rugged, and safe technique with hydrophobic natural deep eutectic solvent as both extractant and analyte protectant was developed and combined with gas chromatography–tandem mass spectrometry to analyze pyrethroid residues in tomatoes. Eight hydrophobic natural deep eutectic solvents were first evaluated as analyte protectants and those with decanoic acid or lactic acid as hydrogen bond donor were demonstrated to be effective in compensating for the matrix effects of pyrethroids in the gas chromatography system. Hence, they were added to solvent standards for correcting the quantitation errors instead of matrix‐matched calibration standards. Then the abilities of these acid‐based deep eutectic solvents to extract pyrethriods from tomatoes were evaluated. Results showed the recoveries of all pyrethroids reached to over 80% with only 5 mL menthol:decanoic acid (1:1) used, and good phase separation was easily achieved without the addition of inorganic salt in the extraction step, indicating hydrophobic natural deep eutectic solvent could be a green substitute for acetonitrile in the quick, easy, cheap, effective, rugged, and safe extraction. Compared with the conventional method, the proposed protocol improved the recoveries, reduced the matrix effects, and simplified the extraction step, demonstrating to be an effective, fast, and green method.  相似文献   
4.
A simple and sensitive surface-enhanced Raman spectroscopy (SERS) method for the detection of safranine T (ST) and Hg2+ using silver nanoparticles (AgNPs) as substrate was developed. ST can absorb on the surface of AgNPs through electrostatic interaction, the electromagnetic effect combined with chemical adsorption effect give a notable Raman enhancement for ST. The presence of Hg2+ well decreased the absorbed ST molecules on AgNPs, leading to a significant decrease of SERS signals thus enabling to detect Hg2+. The determination conditions for SERS, including the amount of AgNPs, the concentration of NaCl, the concentration of HCl, the concentration of ST and the reaction time, were optimised. Under the optimised experimental conditions, good linear responses were obtained for ST and Hg2+ in the concentration ranges of 0.01–4.0 μmol L?1 (3.5–1403.4 ng mL?1) and 0.01–2.0 μmol L?1 (2.0–401.2 ng mL?1), the limit of detection were 3.0 nmol L?1 (1.1 ng mL?1) and 2.0 nmol L?1 (0.4 ng mL?1), respectively. The present method was subsequently applied to the determination of ST in tomato sauces and Hg2+ in environmental waters, the recoveries of ST and Hg2+ in spiked samples are 95.5–107.8% and 91.4–110.8 %, respectively.  相似文献   
5.
高效液相色谱法测定转基因番茄果实中的白藜芦醇   总被引:9,自引:0,他引:9  
王明月  吕岱竹  尹桂豪  贺利民 《色谱》2003,21(3):258-259
 采用高效液相色谱梯度洗脱法测定转基因番茄果实中白藜芦醇的含量。使用μ-Bondapak C18柱,以甲醇-水为流动相,采用紫外检测器在306 nm处对样品中的白藜芦醇进行测定,外标法进行定性定量分析。测定结果表明,白藜芦醇在1-50 mg/L时其峰面积与相应的质量浓度有良好的线性关系,其线性相关系数为0.9998,2个样品测定(n=6)的相对标准偏差(RSD)分别为1.51%和2.38%。平均回收率为98.5%。最小检测量为0.01 mg/kg。测定结果显示:该方法灵敏可靠,具有简便 重现性好的特点。  相似文献   
6.
荧光分析法测定维生素C   总被引:17,自引:1,他引:16  
维生素C经Cu2 氧化为脱氢抗坏血酸,与苯甲酸及十六烷基三甲基溴化铵产生荧光协同增敏作用。提出一种新的测定维生素C的高灵敏荧光分析法,建立了测定维生素C的适合条件。该方法的的线性范围为0.02~8.0μg/mL,检出限为0.006 5μg/mL。对3.0μg/mL的维生素C测定6次,测定结果的相对标准偏差为0.12%。将该法用于西红柿、果珍以及维生素C药片中维生素C含量的测定,加标回收率为96.7%~100.5%。  相似文献   
7.
本文提出用2,6-二氯靛酚纳(以下简写DIS)作氧化剂动力学分光光度测定L-抗坏血酸的新方法。DIS与L-抗坏血酸混合.在固定时间间隔于611nm处测得吸光度A值的变化(△A/△t)与抗坏血酸含量成线性关系。线性范围为0~12mg/L。在样品处理时采用偏磷酸作为提取剂,以减缓抗坏血酸被氧化的速度结果表明,该方法有较高灵敏度,且操作简便,试剂易得,容易推广,是测定水果和蔬菜中L-抗坏血酸的好方法。  相似文献   
8.
高效液相色谱法测定西红柿中克线磷残留量   总被引:5,自引:0,他引:5  
包宏  夏民洲  胡兹苓 《色谱》1994,12(3):213-214
高效液相色谱法测定西红柿中克线磷残留量包宏,夏民洲,胡兹苓(南京林业大学南京210037)1前言克线磷(fenamiphos),商品名Nemacur,是防治作物根结、孢囊与自由线虫的杀线虫农药 ̄[1]。对它的残留分析,有气相色谱法和薄层色谱法等 ̄[2...  相似文献   
9.
Xie L  Ying Y  Ying T  Yu H  Fu X 《Analytica chimica acta》2007,584(2):379-384
VIS-NIR spectroscopy combined with multivariate analysis after the appropriate spectral data pre-treatment has been proved to be a very powerful tool for judgment of the relative pattern of the objects that have very similar properties. In this study, seventy transgenic tomatoes with antisense LeETR2 and 94 of their parents, non-transgenic ones were measured in VIS-NIR diffuse reflectance mode. Principal component analysis (PCA), discriminant analysis (DA) and partial least-squares discriminant analysis (PLSDA) were applied to classify tomatoes with different genes into two groups. Calibrations were developed using PLS regression with the leave-one-out cross-validation technique. The results show that differences between transgenic and non-transgenic tomatoes do exist and excellent classification can be obtained after optimizing spectral pre-treatment. The correct classifications for transgenic and non-transgenic tomatoes were both 100% using PLSDA after derivative spectral pre-treatment. The raw spectra with PLSDA model after the second derivative pre-treatment had the best satisfactory calibration and prediction abilities, with rc = 0.97964, root mean square error of calibration (RMSEC) = 0.099, rcv = 0.97963, root mean square error of cross-validation (RMSECV) = 0.0993 and a factor. The results in the present study show VIS-NIR spectroscopy together with chemometrics techniques could be used to differentiate transgenic tomato, which offers the benefit of avoiding time-consuming, costly and laborious chemical and sensory analysis.  相似文献   
10.
Tomato mosaic virus (ToMV) is one of the economically damageable Tobamovirus infecting the tomato in Egypt that has caused significant losses. It is therefore of great interest to trigger systemic resistance to ToMV. In this endeavor, we aimed to explore the capacity of ZnO-NPs (zinc oxide nanoparticles) to trigger tomato plant resistance against ToMV. Effects of ZnO-NPs on tomato (Solanum lycopersicum L.) growth indices and antioxidant defense system activity under ToMV stress were investigated. Noticeably that treatment with ZnO-NPs showed remarkably increased growth indices, photosynthetic attributes, and enzymatic and non-enzymatic antioxidants compared to the challenge control. Interestingly, oxidative damage caused by ToMV was reduced by reducing malondialdehyde, H2O2, and O2 levels. Overall, ZnO-NPs offer a safe and economic antiviral agent against ToMV.  相似文献   
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