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液相,当然用过.用茚三酮反应液体.日立AMINO ANALYZER 8800.梯度洗脱. 上海天美有卖的.系统稍微优点复杂.柱后衍生。有PH1~PH5四种缓冲液,反应液。准确度高。 还有岛津有款用荧光检测器,也用柱后衍生的梯度洗脱。好象NH4Cl 高中说过,它受热变成NH3, HCl而挥发的吧.温度没有这么高。我只是这么臆想。结晶紫终点蓝绿色是最好判断的指示剂了。不能是蓝色,也不能是亮绿的那种。实际是到了紫色到蓝色时候,再滴1~2滴。变成蓝绿色。
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先检查一下柱塞,可能是它坏了!
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用气相,我们这边用的检测器是用FPD.
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不同的基质对某些组分的提取有影响。但黄瓜中的这几种农残我也用同样的标准分析过,回收率是符合要求的,所以应该是前处理过程中的损失。
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ppm是百万分之一的量啊,我们通常检的在1ppm以下
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連字號"-"唸hyphen
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可以重蒸吧!?!
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是可以用电位滴定的,甲基橙的变色域为3.4~4.4之间,用酸度计来指示终点的到达不就好了吗
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这发到国标版、原子吸收版,可能更好些吧。
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我买过卤肉,那吃的肉就没有肉味。真郁闷
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干物质含量=(常态含量*100)/(100-水分%)
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应该有影响建议同样条件
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补充:上述两个词是我在翻译欧盟最新农残质量控制程序中遇到的,为方便讨论,我将整段摘录如下,另附其英文版全文:Acceptable limits for a individual recovery result should normally be in the...
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补充:上述两个词是我在翻译欧盟最新农残质量控制程序中遇到的,为方便讨论,我将整段摘录如下,另附其英文版全文:Acceptable limits for a individual recovery result should normally be in the range of the mean recovery +/- 2x %RSD and may be adjusted using repeatability (validation) and intra-laboratory reproducibility (routine on-going recovery) data. Recoveries outside this range usually require re-analysis of the batch but may be acceptable in certain justified cases. Where the individual recovery is unacceptably high and no residues are detected, it is not necessary to re-analyse the samples to prove the absence of residues. However, consistently high recovery should be investigated. If a significant trend occurs in recovery, or potentially unacceptable (beyond +/-20 %RSD) results are obtained, the cause(s) must be investigated. In order to assure the correct execution of the whole procedure for each individual sample and the correct injection of each final sample extract in the GC- or LC-system, the use of one or? more quality control (QC-) internal standards, so-called procedurale? and instrument? internal standards, is recommended. These compounds, which are added to the samples prior to extraction and to the final sample extract just before injection, should be chosen to be outside of the target pesticide scope and should preferably represent the entire spectrum of pesticides in terms of polarity and susceptibility to degradation. The recovery of these QC-standards should be within the limits specified by the laboratory but at least within the abovementioned range for individual recovery. 欧盟农残质量控制程序
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丙酮:正己烷1:9活化
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国内的情形我都不太清楚的,就知道磺酰脲类除草剂很容易产生抗性,因此有个合理使用规则,对此类农药的使用次数,时间都有严格的规定。国外一般情况下对推荐,但是不是必须的,在label上列明resistance management, 表明这个产品是哪一类的 (比如group 1, Group 1C)之类的除草剂,杀虫剂,或者杀菌剂。然后写明一些防抗性产生措施。至于怎么做这个抗性试验,暂时还没到我的工作内,所以还没有认真研究。不过这个施药次数的制定应该有guideline的,有时间我找找看。
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前来领奖了
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目前有生物积累的农药基本上禁止使用了,不必过于担心累积作用。人体内有两种蛋白酶:多功能氧化酶和解毒酶,这两种蛋白酶对进入体内的少量可以起到清除作用,所以只要不是大量、长期进入都不会有明显毒害作用
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新的检测方法、植物修复等好像还是可以的。
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这个~去某些检测部门学习一段时间最快吧?
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我们用的是湿法消解!!