Sample handling and preparation can have a substantial effect on an analytical method\u2019s variability and data quality.\u00a0 It is important to consider and address the risks associated with sample preparation as part of the method development process.\u00a0 This requires carefully designed and executed experiments and clear documentation in the method to give the analyst an effective analytical control strategy. Through proper technique, the choice of reproducible consumables and method lifecycle approaches, including an Analytical Target Profile (ATP), risk assessment (RA) and analytical control strategy (ACS), an analyst can effectively mitigate risk and improve the robustness of their analytical methods.<\/p>\n
Sample preparation is an integral part of the analytical method and is often the most time-consuming step.\u00a0 Method robustness and transfer problems frequently result from issues with sample preparation.1<\/sup>\u00a0Even a thoughtfully designed LC analytical method may yield poor results due to some common errors that occur well in advance of the chromatographic separation. Through proper technique, the choice of certified clean, reproducible consumables<\/a> and method lifecycle approaches such as creating an Analytical Target Profile, conducting an Analytical Quality by Design (AQbD) risk assessment, and implementing an appropriate Analytical Control Strategy, an analyst can mitigate the risk of method failure.<\/p>\n Here are some <\/strong>consi<\/strong>derations to help control method variability by reducing errors in sample handling and preparation:<\/strong><\/p>\n The ATP identifies critical method requirements and establishes the acceptance criteria for evaluating steps in sample handling and preparation.\u00a0 The ATP should include the method\u2019s allowable accuracy, precision, specificity and sensitivity requirements as these will influence acceptable sample preparation.\u00a0 For more information on establishing a method\u2019s analytical target profile, see\u00a0“Defining the Analytical Target Profile”, Pharmaceutical Engineering,<\/em>2<\/sup><\/p>\n Perform a sample handling Risk Assessment by evaluating each of the steps associated with the sample prior to analysis (e.g. by HPLC).\u00a0 Consider how each step might impact the analytical results:<\/p>\n Once the sample enters the lab, there are a number of potential challenges getting the sample ready for chromatographic or spectroscopic analysis.\u00a0 These include sample uniformity, choice of diluent and extraction technique.\u00a0 For tablets, if ground or weighed, the resulting particles should be reasonably uniform.\u00a0 Similarly, a suspension must be well mixed before it is sampled to ensure the solution is representative. Extraction of the analyte from the matrix is probably one of the most critical steps as it is affected by analyte solubility in the diluent, and the type of mixing and length of time. The diluent should be chosen based on solubility experiments for the analyte.<\/p>\n For a method to perform consistently, mixing should be well characterized (type of mixing, duration, speed, etc.). Preparation of the solution for analysis often involves weighing, pipetting or dilution steps, typically using volumetric flasks.\u00a0 This points to the importance of good training and laboratory proficiency demonstrations for laboratory scientists.\u00a0 Additionally, it may be necessary to evaluate various sample weights and volumes to assure the reportable results will meet the accuracy and precision criteria stated in the ATP.\u00a0 The results from these experiments should be documented in the Method Development Report.\u00a0 The outcomes, in terms of acceptable experimental parameters for the routine application of the method, should be documented in the method as elements of the ACS, with expectation that they will not be changed without appropriate justification.<\/p>\n An aspect sometimes overlooked is the filtering process for analytical solutions.\u00a0 Filtering is necessary to remove particles, but it can have unintended effects such as adsorptive losses of the analyte. In addition to choosing the proper filtration products, this effect can be overcome by discarding the first few milliliters of filtrate, a volume that should be determined empirically.\u00a0 Finally, it is important to evaluate stability for analytical solutions.\u00a0 Various factors, such as light, temperature and time may result in changes to the solutions such as the loss of analyte or an increase in degradants.\u00a0 Solution stability should be investigated as part of the method development process and documented in the method as part of the ACS.<\/p>\n Even with a well-developed method, we can expect to see variations from day to day, analyst to analyst and lab to lab.\u00a0 Experiments conducted on the same sample on multiple days by the same analyst, and by different analysts, can be used to evaluate expected variability.\u00a0 If the variability is high relative to the requirements established in the ATP, it may be necessary to investigate further to understand the source. Perhaps the greatest challenge is with method transfer to another laboratory.\u00a0 If initial transfer experiments are not successful, it may be necessary to carefully review the existing ACS, and potentially return to the AQbD RA with particular emphasis on those elements that may be different in the receiving laboratory.<\/p>\n When the sources of variability associated with the various risk factors have been identified and experimental controls on procedures, consumables, and reagents have been established, these constitute the Analytical Control Strategy (ACS).\u00a0 The ACS should be well documented in the method to assure consistent application, including controls for reagents and equipment.\u00a0 For further guidance on Analytical Control Strategies, see Analytical Control Strategy Elisabeth Kovacs, et al.\u00a0 USP PF 42(5) Stimuli to the Revision Process5<\/sup>.<\/p>\n Following these six tips can greatly reduce variability, effectively mitigating risk, improving the robustness of analytical methods, and improving data quality.<\/span><\/p>\n Sample handling and preparation can have a substantial effect on an analytical method\u2019s variability and data quality.\u00a0 It is important to consider and address the risks associated with sample preparation as part of the method development process.\u00a0 This requires carefully designed and executed experiments and clear documentation in the method to give the analyst an…<\/p>\n","protected":false},"author":139,"featured_media":2550,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_titles_title":"Controlling Method Variability: Key Sample Handling Approaches | Waters Blog","_seopress_titles_desc":"Sample handling and preparation impact method variability and data quality. Addressing associated risks in method development requires well-designed documentation.","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"none","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"both","_seopress_redirections_param":"","_seopress_redirections_type":301,"_seopress_analysis_target_kw":"","_seopress_news_disabled":"","_seopress_video_disabled":"","_seopress_video":[],"_seopress_pro_schemas_manual":[],"_seopress_pro_rich_snippets_disable_all":"","_seopress_pro_rich_snippets_disable":[],"_seopress_pro_schemas":[],"_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","footnotes":""},"categories":[25],"tags":[26,175,279,176],"class_list":["post-4771","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-pharmaceutical","tag-method-development","tag-method-modernization","tag-methods","tag-methods-development"],"acf":[],"taxonomy_info":{"category":[{"value":25,"label":"Pharmaceutical"}],"post_tag":[{"value":26,"label":"method development"},{"value":175,"label":"method modernization"},{"value":279,"label":"methods"},{"value":176,"label":"methods development"}]},"featured_image_src_large":["https:\/\/www.waters.com\/blog\/wp-content\/uploads\/card-1-sample-handling_final-1024x536.png",1024,536,true],"author_info":{"display_name":"Waters Staff","author_link":"https:\/\/www.waters.com\/blog\/author\/waters_staff\/"},"comment_info":"","category_info":[{"term_id":25,"name":"Pharmaceutical","slug":"pharmaceutical","term_group":0,"term_taxonomy_id":25,"taxonomy":"category","description":"We bring high-value technologies designed to solve critical, analytical problems. We enable profound discoveries, optimize lab operations and ensure regulatory compliance. We help customers turn global industry challenges into the medicines that offer hope.","parent":0,"count":101,"filter":"raw","term_order":"0","cat_ID":25,"category_count":101,"category_description":"We bring high-value technologies designed to solve critical, analytical problems. We enable profound discoveries, optimize lab operations and ensure regulatory compliance. We help customers turn global industry challenges into the medicines that offer hope.","cat_name":"Pharmaceutical","category_nicename":"pharmaceutical","category_parent":0}],"tag_info":[{"term_id":26,"name":"method development","slug":"method-development","term_group":0,"term_taxonomy_id":26,"taxonomy":"post_tag","description":"","parent":0,"count":16,"filter":"raw","term_order":"0"},{"term_id":175,"name":"method modernization","slug":"method-modernization","term_group":0,"term_taxonomy_id":175,"taxonomy":"post_tag","description":"","parent":0,"count":4,"filter":"raw","term_order":"0"},{"term_id":279,"name":"methods","slug":"methods","term_group":0,"term_taxonomy_id":279,"taxonomy":"post_tag","description":"","parent":0,"count":10,"filter":"raw","term_order":"0"},{"term_id":176,"name":"methods development","slug":"methods-development","term_group":0,"term_taxonomy_id":176,"taxonomy":"post_tag","description":"","parent":0,"count":7,"filter":"raw","term_order":"0"}],"_links":{"self":[{"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/posts\/4771","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/users\/139"}],"replies":[{"embeddable":true,"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/comments?post=4771"}],"version-history":[{"count":0,"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/posts\/4771\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/media\/2550"}],"wp:attachment":[{"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/media?parent=4771"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/categories?post=4771"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.waters.com\/blog\/wp-json\/wp\/v2\/tags?post=4771"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}1. Create an Analytical Target Profile (ATP)<\/h3>\n
2. Conduct an AQbD Sample Handling Risk Assessment<\/h3>\n
\n
3. Address Critical Risk Factors with Proper Technique<\/h3>\n
4. Post-Extraction Considerations<\/h3>\n
5. Sample Preparation and Method Robustness<\/h3>\n
6. Create and Implement an Analytical Control Strategy<\/h3>\n
References:<\/h3>\n
\n