糖腈乙酰酯衍生气相色谱法测定土壤水解性单糖

通过对糖腈乙酰酯衍生条件的优化,建立了一种测定土壤水解性单糖的糖腈乙酰酯衍生气相色谱分析方法。8种单糖线性范围为10～640!g,检出限(3S/N)在1.4～4.2ng之间,样品加标平均回收率为100.1%,相对标准偏差(RSD)为1.5～6.3%。试验结果表明该方法操作简便快速、灵敏度高,可准确可靠地应用于土壤单糖含量的测定。     

气相色谱法测定土壤及水中三氯苯残留量

三氯苯是化学工业和合成农药的重要原料。在国外,三氯苯被列为必须监测的土壤污染物之一。     

振荡萃取气相色谱法测定土壤中的苯系物

振荡萃取气相色谱法测定土壤中的苯系物适用范围广,操作简便易行,且本方法精密度和准确度好,苯系物回收率在８２％￣１０５％,苯的最低检出限为０．０１ｍｇ／ｋｇ。     

气相色谱法测定食品中的三氯杀螨醇残留量

本文介绍了食品中三氯杀螨醇残留量的气相色谱测定法，榈中的三氯杀螨醇经提取净化后，用气相色谱法（电子捕获检测器）测定，有较好的分离效果和重现性，最低检出浓度为１００ｎｇ／Ｌ。允许差：相对偏差≤５０％     

气相色谱法测定水稻中嘧啶氧磷的残留量及其在稻田水和土壤中的消…

用丙酮提取，经水－二氯甲烷液－液分配净化，气相色谱ＦＰＤ检测器的Ｐ滤光片测定嘧啶氧磷的水稻土壤，水中的残留量，其回收率为：糙米９５．０－９７．０％，稻杆８６．４－９６．７％，稻壳８３．２－９１．７％，土壤８９．５－９６．５％，水８０．０－８０．７％。土壤中半衰期为６．２３－７．９３天，稻田水中０．８５－３．９３天。测得终点残留量糙米≤０．０８ｍｇ／ｋｇ，稻壳≤０．５ｍｇ／ｋｇ，稻杆≤０．２４ｍｇ／     

气相色谱法同时测定土壤中13种三嗪类除草剂残留量的方法研究

采用气相色谱-氮磷检测器（GC—NPD）方法,建立了同时测定土壤中13种三嗪类除草剂（脱乙基阿特拉津、莠去通、西玛津、莠去津、扑灭津、特丁津、敌草净、赛克津、西草净、莠灭净、扑草净、异丙净、甲氧丙净）残留量的方法。土壤样品用乙腈-水混合提取剂经超声波提取20min,弗罗里硅土（Florisil）固相萃取柱净化后,毛细管柱分离样品,NPD测定。结果表明,13种三嗪类除草剂在0．05-5．0mg·L^-1范围内线性关系良好,相关系数均大于0．999;添加回收率在72．7％～128．2％之间;相对标准偏差在0．4％～20．5％;方法的检出限在0．001-0．005mg·kg^-1之间。     

Determination of neutral sugars in soil by capillary gas chromatography after derivatization to aldononitrile acetates

We have quantified ribose, rhamnose, arabinose, xylose, fucose, mannose, glucose, and galactose in soil by gas chromatography (GC) simultaneously after converting to aldononitrile acetate derivatives. A recommended single-hydrolytic step by 4 M trifluoroacetic acid (TFA) at 105 °C for 4 h was more effective for releasing soil neutral sugars from non-cellulosic carbohydrates and better suited to our purification procedure compared with the sulphuric acid hydrolysis. Linearity of the GC detection for each neutral sugar was in the range of 10-640 μg ml⁻¹ and the recovery of neutral sugars from the spiked soil samples ranged from 76% to 109.7%. The coefficients of variation of the neutral sugars in four soils were lower than 2.0% for the instrument and 4.6-7.6% for the whole determination procedures. Compared with the trimethylsilyl (TMS) derivatization, the recovery of our newly modified method was more satisfactory and the reproducibility of ribose was improved significantly. Moreover, the aldononitrile acetate derivative was more stable than TMS derivative. Therefore, it is a promising approach suitable for a routine use in the quantitative analysis of soil neutral sugars, since it is fast, sensitive, and reproducible.     

Determination of nitrate in soil by second derivative ultraviolet spectrometry

Abstract

A second derivative UV‐spectrometry method is described for the determination of nitrate in soils. Ammonium, nitrite, and urea may be determined in the same extract. The method generally requires no pretreatment of soil extracts, and hence is very rapid. It is largely free from interferences. Recoveries of added nitrate in four soils by the proposed method compared favourably with the phenoldisulphonic acid method.     

浓硫酸纯化-气相色谱法测定土壤中拟除虫菊酯农药残留

建立了土壤中拟除虫菊酯类农药新的前处理方法。样品以乙腈提取,浓硫酸-乙醇进行纯化,毛细管柱气相色谱法测定土壤中的拟除虫菊酯农药。结果表明:4种菊酯在3种土壤样品中的添加回收率在84.14%～105.51%之间,变异系数为1.24%～5.82%。该方法具有省时、省溶剂、操作简单、纯化效果好、实用性强的特点。     

离子色谱法测定土壤有效硫含量

以pH 4.5～8.0范围内的土壤为分析对象,建立离子色谱测定土壤有效硫含量的分析方法.采用0.01:0.01(mol/L)CaCl2-KH2PO4浸提剂提取土壤有效硫,提取液经离子色谱分析,外标法定量.研究结果表明,实验采用的离子色谱条件能有效分离土壤有效硫和干扰组分,定量方法线性良好,相关系数r达0.9997,精密...     

Multiresidue analysis of pesticides in soil by gas chromatography with nitrogen-phosphorus detection and gas chromatography mass spectrometry

A rapid multiresidue method for the simultaneous determination of 25 fungicides and insecticides in soil was developed. Soil samples are extracted by sonication with a water-acetonitrile mixture, and the pesticides are partitioned into dichloromethane. Final determination was made by gas chromatography (GC) with nitrogen-phosphorus detection (NPD). Confirmation analysis of pesticides was carried out by GC-MS in the selected ion monitoring (SIM) mode. The identification of compounds was based on retention time and on comparison of the primary and secondary ions. The average recovery by the GC-NPD method obtained for these compounds varied from 68.5% to 112.1% with a relative standard deviation between 1.8% and 6.2%. The GC-NPD method presents good linearity over the range assayed 50-2000 microg/L, and the detection limit for the pesticides studied varied from 0.1 to 10.4 microg/kg. The proposed method was used to determine pesticide levels in soil samples from experimental greenhouse pepper cultivation.     

Determination of pyrantel in swine liver by flame ionization gas chromatography and confirmation by gas chromatography/mass spectrometry

During an evaluation of the gas chromatography/mass spectrometry (GC/MS) confirmatory procedure of Lynch and Bartolucci for pyrantel residues in swine tissues, we developed a GC flame ionization method for quantitating pyrantel residues in extracts of swine liver. The method was subjected to trial principally in the laboratories of Biospherics, Inc., using control liver, fortified control liver, and incurred liver tissue samples. Although the method does not meet all of the current Food and Drug Administration criteria, it compares favorably to the official determinative method. Portions of the same extract can be used for quantitation and for GC/MS confirmation, true recoveries appear to be slightly higher, and an internal standard is not required. The precision of this method equals or exceeds that of the official determinative method.     

1,2∶5,6-二-氧-异亚丙基-D-甘露醇的气相色谱分析

本文报道了气相色谱法分析1，2：5，6-二-氧-异亚丙基-D-甘露醇。选择马比妥作为内标物。色谱条件如下：FID检测器，5%SE-30/Shimalite W(AW-DMCS)80-100l目固定相；柱湿及气化室分别为180℃和250℃。该方法处理简单，定量准确，易于推广应用，适宜于常规分析与质量控制。     

Highly sensitive analysis of iodide anion in seaweed as pentafluorophenoxyethyl derivative by capillary gas chromatography

A simple and sensitive gas chromatography (GC) method is described for the trace analysis of iodide anion (iodide) in processed seaweed as an organic derivative. The method is based on the derivatization of aqueous iodide extracted from seaweed with 2-(pentafluorophenoxy)ethyl 2-(piperidino)ethanesulfonate in toluene using tetra-n-hexylammonium bromide as a phase-transfer catalyst. The resulting pentafluorophenoxyethyl iodide is highly responsive to an electron-capture detector (ECD) and was analyzed by GC-ECD, giving a low detection limit of approximately 2.7 nM (2.7 fmol/microL injected). Interferences of some common anions in the analysis of iodide were studied and proved to be minimal. Application of the method to the analysis of iodide in processed seaweed was performed.