Critical role of Method Validation in Chemical Analysis

每个分析都需要选择一个方法，可以帮助您实现所需目标。如果有既定的方法，您应该考虑自己幸运，因为这将节省验证在采用之前验证该方法所需的努力和时间。

Several options are available to you for selection of the method to suit your analysis requirements. Such options include survey of standard analytical textbooks, research journal publications, Google search, etc. You will come across several methods in your Google search but this can add to further confusion as the method selected may not be suitable for your analysis requirements.

在你的方法你als的选择o have to keep into consideration other factors such as:

• Cost of analysis
• Availability of required reagents and standards
• 所需工具设施的可用性
• 培训人力的可用性
• Time requirement for analysis
• 方式的简单性

必须记住，最简单的方法可能不是理想的方法，因此您必须仔细评估上面列出的考虑因素的选择。

Let us assume that you have decided on the method of your choice and are planning to put it into routine use. However, at this stage it is essential to validate it so as to gain confidence that the data obtained using the method will be above question and will meet the prescribed regulatory requirements.

What is method validation and why it is required?

方法验证是一系列实验研究，确定所考虑的方法将符合预期应用的要求。这一要求是由于几种考虑因素，例如：

• The selected method is not specific to the analyte(s) of interest
• The matrix composition of the sample is different from the composition in the method of choice
• The required concentration range is different from the one in the method selected or detection limits required are different
• The method is to be adapted to a different make of instrument
• Changes have been incorporated in the existing method to meet the requirements of the application

What all is covered under method validation?

Before undertaking the validation process it should be ascertained using reference standards that the response of the analytical measurement is on account of the analyte of interest and not due to any other chemical species. After this has been established you may proceed with the validation which evaluates the following method specific features:

选择性和特异性

选择性和特异性通常是同义使用的，但这些是不同的术语。特异性是对样品中存在的特定分析物的技术的明确响应，而选择性可以适用于对具有类似化学和物理特性的一组分析物的集体反应。选择的方法应符合在刻意添加的干预率的情况下选择性和灵敏度的标准，这些干预率可以在调查中的样本中预期

准确性

准确性是观察值与接受或转介价值的接近程度。为此目的，样品可以用分析物掺入，使得基础样品基质组合物保持不变。

Precision

精度是测试结果再现性的量度。应记住，高度的精度并不一定意味着高度的精度，因为由于测量中固有的错误，相同的结果可以重复多次，但可以从精确值中除去结果。

检测极限and limit of quantitation

定量极限是分析物的最低量，其可以用可接受的精度水平定量确定。另一方面，检测限是可以通过该方法检测但不一定量化的最低浓度。检测限始终低于定量限制。

Linearity

Linearity is the ability of the method to provide a response which is in direct relation to the analyte concentration. The linearity range should be as large as possible and should be established with the help of multipoint calibration with at least 6 to 10 points

坚固性

坚固性is the confidence that you can place on the selected method. In other words the results should be reproducible in your laboratory or in any other laboratory or even when an analysis is carried out by a different set of analysts.

鲁棒性

鲁棒性检查了操作参数变化的影响，例如pH或温度的微小变化，以在特定的公差范围内提供结果的能力。

Method validation may appear to be a tedious and time-consuming activity but once the method is validated before adoption it will not let you down under any circumstances.