{"id":1184,"date":"2024-04-11T14:39:10","date_gmt":"2024-04-11T11:39:10","guid":{"rendered":"https:\/\/sisu.ut.ee\/lcms_method_validation\/self-test-9-3\/"},"modified":"2024-04-11T14:39:10","modified_gmt":"2024-04-11T11:39:10","slug":"self-test-9-3","status":"publish","type":"page","link":"https:\/\/sisu.ut.ee\/lcms_method_validation\/self-test-9-3\/","title":{"rendered":"Self test 9.3"},"content":{"rendered":"<div id=\"watupro_quiz\" class=\"quiz-area single-page-quiz\">\n<p id=\"submittingExam13\" style=\"display:none;text-align:center;\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/sisu.ut.ee\/wp-content\/plugins\/watupro\/img\/loading.gif\" width=\"16\" height=\"16\"><\/p>\n\n\n\n<form action=\"\" method=\"post\" class=\"quiz-form\" id=\"quiz-13\" enctype=\"multipart\/form-data\">\n<div class=\"watu-question \" id=\"question-1\" style=\";\"><div id=\"questionWrap-1\" class=\"   watupro-question-id-42\">\n\t\t\t<div class=\"question-content\"><div><span class=\"watupro_num\">1. <\/span>Which of the statements are correct?<\/div><input type=\"hidden\" name=\"question_id[]\" id=\"qID_1\" value=\"42\" class=\"watupro-question-id\"><input type=\"hidden\" id=\"answerType42\" class=\"answerTypeCnt1\" value=\"checkbox\"><!-- end question-content--><\/div><div class=\"question-choices watupro-choices-columns \" id=\"questionChoices42\"><div class=\"watupro-question-choice  \" dir=\"auto\"><input type=\"checkbox\" name=\"answer-42[]\" id=\"answer-id-129\" class=\"answer   answerof-42 \" value=\"129\"><label for=\"answer-id-129\" id=\"answer-label-129\" class=\" answer\"><span><p>The analysis method measures Na<sup>+<\/sup> and K<sup>+<\/sup> content in drinking water with atomic absorption spectroscopy. These ions are always present in high enough quantities so the LoD value is always lower than the concentration of the analytes in the sample. Therefore determination of LoD is not critical.<\/p><\/span><\/label><\/div><div class=\"watupro-question-choice  \" dir=\"auto\"><input type=\"checkbox\" name=\"answer-42[]\" id=\"answer-id-130\" class=\"answer   answerof-42 \" value=\"130\"><label for=\"answer-id-130\" id=\"answer-label-130\" class=\" answer\"><span><p>The goal of the analysis method is to estimate whether the metabolites that indicate the use of an illegal doping are present in the urine of a professional athlete. No LoD value is needed.\u00a0<\/p><\/span><\/label><\/div><div class=\"watupro-question-choice  \" dir=\"auto\"><input type=\"checkbox\" name=\"answer-42[]\" id=\"answer-id-128\" class=\"answer   answerof-42 \" value=\"128\"><label for=\"answer-id-128\" id=\"answer-label-128\" class=\" answer\"><span><p>The analysis method measures protein content in milk by the Kjeldahl method. In the case of this analysis the LoD value is very important.<\/p><\/span><\/label><\/div><div class=\"watupro-question-choice  \" dir=\"auto\"><input type=\"checkbox\" name=\"answer-42[]\" id=\"answer-id-131\" class=\"answer   answerof-42 \" value=\"131\"><label for=\"answer-id-131\" id=\"answer-label-131\" class=\" answer\"><span><p>The analysis method measures whether any mercury is present in food by using cold vapor atomic fluorescence spectroscopy. LoD must be estimated for the method as the mercury level in the sample can often be close to the LoD of the analysis method. Therefore, LoD must be known to interpret the results.\u00a0<\/p><\/span><\/label><\/div><!-- end question-choices--><\/div><!-- end questionWrap--><\/div>\t\t\t\t\t<div style=\"display:none;\" id=\"liveResult-1\">\t\t   \n\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/sisu.ut.ee\/wp-content\/plugins\/watupro\/img\/loading.gif\" width=\"16\" height=\"16\" alt=\"Loading...\" title=\"Loading...\">\u00a0Loading...\t\t\t\t\t<\/div>\t\n\t\t\t<\/div> \n\t   \t<p id=\"liveResBtn-42\" style=\"clear:both;\"><input type=\"button\" id=\"liveResultBtn42\" class=\"liveResultBtn1 watupro-live-result-btn\" value=\"See Answer\" onclick=\"WatuPRO.liveResult(42, 1);\"><\/p>\n\t   <div class=\"watu-question \" id=\"question-2\" style=\";\"><div id=\"questionWrap-2\" class=\"   watupro-question-id-43\">\n\t\t\t<div class=\"question-content\"><div><span class=\"watupro_num\">2. <\/span>Which the following statement is true?<\/div><input type=\"hidden\" name=\"question_id[]\" id=\"qID_2\" value=\"43\" class=\"watupro-question-id\"><input type=\"hidden\" id=\"answerType43\" class=\"answerTypeCnt2\" value=\"checkbox\"><!-- end question-content--><\/div><div class=\"question-choices watupro-choices-columns \" id=\"questionChoices43\"><div class=\"watupro-question-choice  \" dir=\"auto\"><input type=\"checkbox\" name=\"answer-43[]\" id=\"answer-id-132\" class=\"answer   answerof-43 \" value=\"132\"><label for=\"answer-id-132\" id=\"answer-label-132\" class=\" answer\"><span><p>Data in Plot A are homoscedastic\u00a0<\/p><p><img decoding=\"async\" class=\"alignnone wp-image-405\" style=\"\" src=\"https:\/\/sisu.ut.ee\/wp-content\/uploads\/sites\/130\/image001-2.jpg\" title=\"image001.jpg\" alt=\"image001.jpg\"><\/p><\/span><\/label><\/div><div class=\"watupro-question-choice  \" dir=\"auto\"><input type=\"checkbox\" name=\"answer-43[]\" id=\"answer-id-133\" class=\"answer   answerof-43 \" value=\"133\"><label for=\"answer-id-133\" id=\"answer-label-133\" class=\" answer\"><span><p>Data in Plot B are\u00a0<span id=\"docs-internal-guid-6058fa82-7785-6914-384e-f3ade95df664\">heteroscedastic<\/span><\/p><p><img loading=\"lazy\" decoding=\"async\" width=\"373\" height=\"285\" class=\"alignnone wp-image-572\" style=\"\" src=\"https:\/\/multisite.ut.ee\/wp-content\/uploads\/sites\/130\/image002.jpg\" title=\"image002.jpg\" alt=\"image002.jpg\" srcset=\"https:\/\/sisu.ut.ee\/wp-content\/uploads\/sites\/130\/image002.jpg 373w, https:\/\/sisu.ut.ee\/wp-content\/uploads\/sites\/130\/image002-300x229.jpg 300w\" sizes=\"auto, (max-width: 373px) 100vw, 373px\"><\/p><\/span><\/label><\/div><!-- end question-choices--><\/div><!-- end questionWrap--><\/div>\t\t\t\t\t<div style=\"display:none;\" id=\"liveResult-2\">\t\t   \n\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/sisu.ut.ee\/wp-content\/plugins\/watupro\/img\/loading.gif\" width=\"16\" height=\"16\" alt=\"Loading...\" title=\"Loading...\">\u00a0Loading...\t\t\t\t\t<\/div>\t\n\t\t\t<\/div> \n\t   \t<p id=\"liveResBtn-43\" style=\"clear:both;\"><input type=\"button\" id=\"liveResultBtn43\" class=\"liveResultBtn2 watupro-live-result-btn\" value=\"See Answer\" onclick=\"WatuPRO.liveResult(43, 2);\"><\/p>\n\t   <div class=\"watu-question \" id=\"question-3\" style=\";\"><div id=\"questionWrap-3\" class=\"   watupro-question-id-44\">\n\t\t\t<div class=\"question-content\"><div><span class=\"watupro_num\">3. <\/span>Which of the following statements are true:<\/div><input type=\"hidden\" name=\"question_id[]\" id=\"qID_3\" value=\"44\" class=\"watupro-question-id\"><input type=\"hidden\" id=\"answerType44\" class=\"answerTypeCnt3\" value=\"checkbox\"><!-- end question-content--><\/div><div class=\"question-choices watupro-choices-columns \" id=\"questionChoices44\"><div class=\"watupro-question-choice  \" dir=\"auto\"><input type=\"checkbox\" name=\"answer-44[]\" id=\"answer-id-135\" class=\"answer   answerof-44 \" value=\"135\"><label for=\"answer-id-135\" id=\"answer-label-135\" class=\" answer\"><span><p>If LoD is estimated from the standard deviation of residuals, but the data used are not linear, then the LoD value will be overestimated (assuming that in this case the slope of the calibration function does not influence the LoD result significanlty).<\/p><\/span><\/label><\/div><div class=\"watupro-question-choice  \" dir=\"auto\"><input type=\"checkbox\" name=\"answer-44[]\" id=\"answer-id-136\" class=\"answer   answerof-44 \" value=\"136\"><label for=\"answer-id-136\" id=\"answer-label-136\" class=\" answer\"><span><p>S\/N can be used to estimate LoD for chromatographic methods by performing a single measurement of a sample at different concentrations.\u00a0<\/p><\/span><\/label><\/div><div class=\"watupro-question-choice  \" dir=\"auto\"><input type=\"checkbox\" name=\"answer-44[]\" id=\"answer-id-134\" class=\"answer   answerof-44 \" value=\"134\"><label for=\"answer-id-134\" id=\"answer-label-134\" class=\" answer\"><span><p>If CC<sub>\u03b2<\/sub> is estimated by using the standard deviation of blank samples, but the analytical method gives strongly heteroscedastic data, then the LoD estimate is overestimated.\u00a0<\/p><\/span><\/label><\/div><!-- end question-choices--><\/div><!-- end questionWrap--><\/div>\t\t\t\t\t<div style=\"display:none;\" id=\"liveResult-3\">\t\t   \n\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/sisu.ut.ee\/wp-content\/plugins\/watupro\/img\/loading.gif\" width=\"16\" height=\"16\" alt=\"Loading...\" title=\"Loading...\">\u00a0Loading...\t\t\t\t\t<\/div>\t\n\t\t\t<\/div> \n\t   \t<p id=\"liveResBtn-44\" style=\"clear:both;\"><input type=\"button\" id=\"liveResultBtn44\" class=\"liveResultBtn3 watupro-live-result-btn\" value=\"See Answer\" onclick=\"WatuPRO.liveResult(44, 3);\"><\/p>\n\t   <div class=\"watu-question \" id=\"question-4\" style=\";\"><div id=\"questionWrap-4\" class=\"   watupro-question-id-45\">\n\t\t\t<div class=\"question-content\"><div><span class=\"watupro_num\">4. <\/span>Estimate LoD from given data collected from LC-MS\/MS measurements of thiabendazole from tomatoes. For estimating LoD use the approach suggested by ICH that uses standard deviation of residuals.<br>\r\n<table style=\"width: 30%; border-collapse: collapse;\" border=\"1\" cellspacing=\"0\" cellpadding=\"5\"><tbody><tr><td class=\"xl65\" style=\"border: 1px solid black; text-align: center;\"><strong>Concentration (mg\/kg)<\/strong><\/td><td class=\"xl65\" style=\"border: 1px solid black; text-align: center;\"><strong>Intensity<\/strong><\/td><\/tr><tr><td class=\"xl63\" style=\"border: 1px solid black; text-align: center;\">0<\/td><td class=\"xl64\" style=\"border: 1px solid black; text-align: center;\">8261<\/td><\/tr><tr><td class=\"xl63\" style=\"border: 1px solid black; text-align: center;\">0.000534<\/td><td class=\"xl64\" style=\"border: 1px solid black; text-align: center;\">9600<\/td><\/tr><tr><td class=\"xl63\" style=\"border: 1px solid black; text-align: center;\">0.00652<\/td><td class=\"xl64\" style=\"border: 1px solid black; text-align: center;\">48925<\/td><\/tr><tr><td class=\"xl63\" style=\"border: 1px solid black; text-align: center;\">0.0348<\/td><td class=\"xl64\" style=\"border: 1px solid black; text-align: center;\">230899<\/td><\/tr><tr><td class=\"xl63\" style=\"border: 1px solid black; text-align: center;\">0.0816<\/td><td class=\"xl64\" style=\"border: 1px solid black; text-align: center;\">462286<\/td><\/tr><tr><td class=\"xl63\" style=\"border: 1px solid black; text-align: center;\">0.192<\/td><td class=\"xl64\" style=\"border: 1px solid black; text-align: center;\">1127468<\/td><\/tr><tr><td class=\"xl63\" style=\"border: 1px solid black; text-align: center;\">0.408<\/td><td class=\"xl64\" style=\"border: 1px solid black; text-align: center;\">2257172<\/td><\/tr><tr><td class=\"xl63\" style=\"border: 1px solid black; text-align: center;\">0.95<\/td><td class=\"xl64\" style=\"border: 1px solid black; text-align: center;\">3899419<\/td><\/tr><tr><td class=\"xl63\" style=\"border: 1px solid black; text-align: center;\">2.23<\/td><td class=\"xl64\" style=\"border: 1px solid black; text-align: center;\">5851448<\/td><\/tr><tr><td class=\"xl63\" style=\"border: 1px solid black; text-align: center;\">5.07<\/td><td class=\"xl64\" style=\"border: 1px solid black; text-align: center;\">6018480<\/td><\/tr><\/tbody><\/table>For use with ValChrom: <a href=\"https:\/\/sisu.ut.ee\/lcms_method_validation\/st_9-3_1_lod_loq-xls\/\" data-fid=\"57423\">st_9.3_1_lod_loq.xls<\/a>\u00a0<br>\r\n<br>\r\nNotes:<br>\r\nBefore estimating LoD use the plot of absolute residuals to estimate which of the highest calibration levels should be removed from data so that the data would be linear. <span id=\"docs-internal-guid-6058fa82-8b01-018c-0ddd-1962524a6a0b\">Do not set intercept as zero as in case of these data it is known that the intercept can have a non zero value.<\/span>\u00a0<br>\r\n<br>\r\nFor use with ValChrom delete the lines that do not fit and reupload the CSV file.<br>\r\n<br>\r\nPlease write result rounded to 2 significant digits (unit: mg\/kg).<\/div><input type=\"hidden\" name=\"question_id[]\" id=\"qID_4\" value=\"45\" class=\"watupro-question-id\"><input type=\"hidden\" id=\"answerType45\" class=\"answerTypeCnt4\" value=\"textarea\"><!-- end question-content--><\/div><div class=\"question-choices \" id=\"questionChoices45\"><p><input type=\"text\" name=\"answer-45[]\" id=\"textarea_q_45\" class=\"watupro-text\" value=\"\" size=\"60\"><\/p><!-- end question-choices--><\/div><!-- end questionWrap--><\/div>\t\t\t\t\t<div style=\"display:none;\" id=\"liveResult-4\">\t\t   \n\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/sisu.ut.ee\/wp-content\/plugins\/watupro\/img\/loading.gif\" width=\"16\" height=\"16\" alt=\"Loading...\" title=\"Loading...\">\u00a0Loading...\t\t\t\t\t<\/div>\t\n\t\t\t<\/div> \n\t   \t<p id=\"liveResBtn-45\" style=\"clear:both;\"><input type=\"button\" id=\"liveResultBtn45\" class=\"liveResultBtn4 watupro-live-result-btn\" value=\"See Answer\" onclick=\"WatuPRO.liveResult(45, 4);\"><\/p>\n\t   <div style=\"display:none\" id=\"question-5\">\n\t<div class=\"question-content\">\n\t\t<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/sisu.ut.ee\/wp-content\/plugins\/watupro\/img\/loading.gif\" width=\"16\" height=\"16\" alt=\"Loading...\" title=\"Loading...\">\u00a0Loading...\t<\/div>\n<\/div>\n\n<br>\n\t\n\t\t\t<div class=\"watupro_buttons flex \" id=\"watuPROButtons13\">\n\t\t  <div id=\"prev-question\" style=\"display:none;\"><input type=\"button\" value=\"&lt; 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