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建立了离子色谱-电导检测分析不同类型乳制品中硫氰酸盐(SCN-)污染物的方法,重点研究了不同形态样品如固态类(奶粉)、液态类(牛奶)、凝固态类(凝固型酸奶)和半流质态类(炼乳)等乳制品中的硫氰酸盐前处理方法,采用丙酮作为蛋白沉淀剂,有效实现了对各类样品中蛋白质的沉淀和对硫氰酸盐的提取,避免了以往采用乙腈处理样品时容易分层的弊端,方法在0~5.0mg/L浓度范围内具有良好的线性关系,相关系数r为0.9997(n=6),方法检出限(LOD)为0.15~0.5μg/g,方法回收率为95.0%~105.0%,相对标准偏差(RSD)为1.4%~5.6%(n=3)。 相似文献
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应用超高效液相色谱-高分辨质谱法检测合成大麻素JWH-073在人肝微粒体中的Ⅰ相代谢产物,用肝微粒体体外温孵法制备了加入JWH-073的人肝微粒体,从中了解JWH-073在人体内的代谢过程。JWH-073在人肝微粒体中共产生11种Ⅰ相代谢产物,其代谢途径为羟基化、羧基化、脱烷基化和羰基化,其中羟基化为主要途径,羟基化代谢产物有6种。根据代谢方式、代谢发生的位点及代谢产物的响应强度,推荐羟基化代谢产物(编号M4)作为JWH-073在人体尿液中的中毒标记物。在实际工作中仍需要收集人体尿液样品,通过筛查对比其中的主要代谢产物,最终确认JWH-073的代谢标记物。 相似文献
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以双水杨醛缩二氨基硫脲合铜(Ⅱ)[Cu(Ⅱ)-ATBSAD]为中性载体制备PVC膜电极,该电极对SCN-具有优良的电位响应特性。采用紫外光谱技术和交流阻抗技术研究了该电极对SCN-的响应机理。电极在磷酸盐缓冲溶液(pH5.0)中,SCN-浓度在1.0×10-1~1.4×10-7mol/L范围内呈近能斯特响应;斜率为-56mV/pSCN-(26℃);检出限为5.6×10-8mol/L。Cu(Ⅱ)-ATBSAD载体膜电极对SCN-具有较好的选择性,一些常见阴离子对电极的干扰较小。将此电极用于废水中硫氰酸盐含量的测定,结果与高效液相色谱法一致。 相似文献
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提出了波长扫描-光化学反应速差荧光分析同时测定双组分的方法,以核黄素的光分解反应和甲萘醌的光还原反应为例考察了方法的可行性.结果表明,核黄素、甲萘醌浓度分别在(0~1.20)μg/mL和(0~2.70)μg/mL范围内呈良好的线性关系(γ为0.999和0.998).检出限分别为0.22ng/mL和2.6ng/mL(n=11).平均回收率分别为101%、99%. 相似文献
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A highly sensitive fluorimetric method for the determination of fluoride was established. The method was based on quenching of the fluorescence of the Al3+-calcein complex in CCl3COOH-CH3COOK buffer solution by fluoride. The fluorescence emission was measured at lambdaex/lambdaem 480/503 nm, and the experimental variables and interference in this determination were studied. The linear calibration range was 0.8 ng/mL to 150 ng/mL and the detection limit was 0.2 ng/mL. The method was applied to determine fluoride in biological materials. The recovery was in the range of 96.3% to 104.7% and the relative standard deviation was 4.6%. The results obtained from the certified reference material by the present method agreed with the certified values. 相似文献
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A fluorimetric method for the determination of vitamin B12 has been developed. The fluorescence emission was measured at lambda(ex)/lambda(em)275/305 nm in phosphate buffer solution (pH 7.0), and the experimental variables and possible interference were studied. The linear calibration range was 1.000 ng/mL to 100.0 ng/mL with a correlation coefficient of 0.9994 and a detection limit of 0.1 ng/mL. The method is rapid, simple and highly sensitive. It was used to determine vitamin B12 in pharmaceutical preparations. The recovery was 96%-98% and the relative standard deviation was in the range of 1.8%-2.7%. The results agreed with those obtained by spectrophotometry. 相似文献
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以光化学荧光衍生化法测定苋菜红(AM)和直接耐晒嫩黄5GL(DY)2种偶氮色素,研究了同时测定这2种色素混合物的光化学速差动力学荧光分析的原理和方法。AM和DY的浓度分别在0~220ng/mL和0~120ng/mL范围内呈良好的线性关系,相关系数皆为0.999,检出限为0.64ng/mLAM和0.045ng/mLDY。相对标准偏差分别为1.6%(n=8)和1.8%(n=7)。该法用于人工合成混合样品的测定效果良好。 相似文献
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A kinetic spectrophotometric method for determination of trace nitrite in two dynamic ranges (2–100 and 100–500 ng/mL) based on its catalytic effect on the reaction between methylthymol blue and potassium bromate in acidic (sulfuric acid) media is described. The reaction was monitored spectrophotometrically by measuring the decreasing color of methylthymol blue at 437 nm by the fixed‐time method of 4.0 min at 30°C. The detection limit is 0.6 ng/mL, and the relative standard deviations for 50.0 and 250.0 ng/mL nitrite are 1.6% and 1.3%, respectively. The method was used for the determination of nitrite in water samples. 相似文献
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A simple method for the selective and sensitive kinetic spectrophotometric determination of iron (II) is described. The method
is based on the oxidation reaction of reduced phenolphthalein by periodate in alkaline media. The change in absorbance was
measured using the fixed time method. The effect of different variables on the reaction was investigated and optimum conditions
were obtained. The calibration curve was linear in the range 50–3000 ng/mL, and a detection limit of 17 ng/mL was obtained.
The relative standard deviation of ten replicate determinations of 200 ng/mL of Fe(II) was 1.2%. The determination of Fe(II)
in the presence of a 50-fold amount of Fe(III) could be carried out.
This article was submitted by the authors in English. 相似文献
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