#46
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Àëåêñàíäð, íó ìû æå íå â òðåòüåì êëàññå, åé-áîãó. Ìû ñåé÷àñ ïðîâåðÿåì íå ïðàâèëüíîñòü ðåøåíèÿ çàäà÷è, à ïðàâèëüíîñòü âûâîäà óðàâíåíèÿ, ñîãëàñèòåñü, ýòî íåìíîãî ðàçíûå âåùè.
Ïîõîæå, îò Âàñ óñêîëüçàåò ñìûñë ïðÿìîé çàâèñèìîñòè àáñîðáöèè ïðîáû îò êîíöåíòðàöèè àíàëèòà. Âû ñìåùàåòå öåíòð êîîðäèíàò ê íóëþ, âíîñÿ ÷èñëîâóþ ïîïðàâêó, êîòîðàÿ ñàìà ïî ñåáå èìååò êîîðäèíàòû «íóëÿ», è ýòî ñîâåðøåííî íåâåðíî. Ñîãëàñíà ñ ÀëåêñîìÒ ïî ïîâîäó ëèìèòà ëèíåéíîñòè è ïîäà÷è ðåçóëüòàòà â âèäå «íèæå Õ», íî ìåíÿ î÷åíü èíòåðåñóþò ñàìè ðàñ÷åòû, ïîòîìó ÷òî ïðè òàêèõ ïîäõîäàõ äàæå â äèàïàçîíå ëèíåéíîñòè æåëåçî çàíèæàåòñÿ íà 6 ìêìîëü. Âîò òàê äîëæåí âûãëÿäåòü Âàø ãðàôèê è ôîðìóëà ðàñ÷åòà: [Ññûëêè äîñòóïíû òîëüêî çàðåãèñòðèðîâàííûì ïîëüçîâàòåëÿì ] |
#47
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Ìû, êîíå÷íî, íå â òðåòüåì êëàññå, íî îäíàæäû â êîìïàíèè äâóõ èíæåíåðîâ è îäíîãî ýêîíîìèñòà íå ìîãëè âñïîìíèòü ôîðìóëó ðåøåíèÿ êâàäðàòíîãî óðàâíåíèÿ, à ýòî áûëî íóæíî äëÿ ñîñòàâëåíèÿ ïðîãðàììû äëÿ èõ ðàáîòû.
Assandra, Âû ñïðîñèëè ïðî 6,01. ß îáúÿñíèë. Åñëè â ìîåé ôîðìóëå îøèáêà, Âû ìíå ýòî îáúÿñíèòå. Íà öèôðàõ, êàê áóäòî ÿ â òðåòüåì êëàññå. Ïðî êàëèáðîâêè è ôàêòîðû ïîçæå |
#49
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Î ÷åì ñïîðèì?
y=ax+b Ëèáî ìû ñ÷èòàåì ïî ôàêòîðó, ïðåäïîëàãàÿ ÷òî ñìåùåíèÿ íåò (b=0 èëè íåçíà÷èìî) - òîãäà ôàêòîð 185 Ëèáî ìû ñòðîèì ãðàôèê - òîãäà íóæíû åùå òî÷êè èç äèàïàçîíà èçìåðåíèÿ 0 - ÍÅ ÂÕÎÄÈÒ Â ÄÈÀÏÀÇÎÍ. Ââîäÿ 2 òî÷êó (0; 0,026) âû ïîëó÷àåòå ñîâñåì äðóãîé íàêëîí 226. [Èçîáðàæåíèÿ äîñòóïíû òîëüêî çàðåãèñòðèðîâàííûì ïîëüçîâàòåëÿì] Âîçìîæíî ÷òî òàê îíî è åñòü è ìû ïîëó÷èì òî æå ïðè èçìåðåíèè äðóãèõ òî÷åê. Ýòî è áóäåò çíà÷èòü "significant negative intercept" (b=-6!) , è ÷òî ïî ôàêòîðó íåëüçÿ ñ÷èòàòü çíà÷åíèÿ íèæå êàêîãî-òî (ïîäîçðåâàþ ÷òî êàê â èíñòðóêöèè). ß áû ëó÷øå ñìåíèë íàáîð. |
#50
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Ìû íå ïîëó÷èì îäíî è òî æå.
Âîçüìåì ïðîáû ñ àáñîðáöèåé 0.045; 0.084 è 0.190 Ïî ôîðìóëå y = 226,1x-6,01 ïîëó÷àåì Fe: 4.16 (ïî äîñòèãíóòîìó íàìè êîíñåíñóñó íàäî âûäàâàòü êàê < 6.0); 12.98 è 37. Ïî ôîðìóëå y = 185x (âûâåäåííîé, ïðîøó çàìåòèòü, ïî èíñòðóêöèè) ïîëó÷àåì: 8.33; 15.54 è 35.2. Ìîæåò, â êëèíè÷åñêîì ïëàíå ýòî è íåáîëüøàÿ ðàçíèöà â äèàïàçîíå íîðìàëüíûõ è ïîâûøåííûõ çíà÷åíèÿõ, íî íà íèçêèõ… |
#51
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Áûëà ïðîâåäåíà ñåðèÿ èçìåðåíèé êàëèáðîâî÷íîãî ðàñòâîðà ðàçâîäèìîãî ïîñëåäîâàòåëüíî â 2 ðàçà (30; 15; 7,5: 3,75 è ò.ä.). Ðåçóëüòàòû îïò. ïë. â ôàéëå Exel. Òàì æå âèäíû âñå âû÷èñëåíèÿ. Íà ãðàôèêå ðàñ÷åò ïî ôàêòîðó (185,4) è ïî êàëèáðîâêå (äâå òî÷êè 0 è 30).
Âèäíî, ÷òî îáå çàâèñèìîñòè äîñòàòî÷íî ëèíåéíû.  èäåàëå òî÷êè äîëæíû áûëè ëåæàòü íà ïðÿìîé îò îäíîãî óãëà äî äðóãîãî. Èäåàëà, åñòåñòâåííî, íåò. Ëè÷íî ìíå âàðèàíò ñ êðóæî÷êàìè íðàâèòñÿ áîëüøå. Òî÷êà 15 â îáîèõ ñëó÷àÿõ íåñêîëüêî îòêëîíèëàñü îò ïðÿìîé, ñïèøåì ýòî íà ïðèáîð, íå ÿïîíåö âñå-òàêè. Áûëè è áîëåå êðàñèâûå âàðèàíòû, ïðîñòî äàííûå íå ñîõðàíèëèñü.  ïîñòå ¹18 åñòü äàííûå èçìåðåíèÿ ïðîá: Ñäåëàë ðàçâåäåíèÿ êàëèáðàòîðà Ðýíäîêñ (R) â 10 è 20 ðàç. Ïðîáó ñëó÷àéíîãî ïàöèåíòà (P) - â 10 ðàç. Æåëåçî â Ðýíäîêñå - 35,7 (ïî ïàñïîðòó). Ïî êàëèáðàòîðó èç íàáîðà (30) è äèñò âîäå áûë ñäåëàí ðàñ÷åò Òàì ïðèâåäåíû äàííûå èçìåðåíèÿ îïòè÷åñêîé ïëîòíîñòè ñ ïðèáîðà. Íà îñíîâàíèè ýòèõ çíà÷åíèé ïðîâåäåí ðàñ÷åò äâóìÿ ñïîñîáàìè: ïî êàëèáðîâêå ( ïî äâóì òî÷êàì (0 è 30)) è ïî ôàêòîðó .  ïðàâûõ ñòîëáöàõ îæèäàåìûå ðåçóëüòàòû ñ ó÷åòîì ðàçâåäåíèÿ. ______________________Ðåçóëüòàòû__________________ îæèäàåìûå ðåçóëüòàòû (ñ ó÷åòîì ðàçâåäåíèÿ) ïðîáà___________ïî êàëèáðîâêå_____ïîF_________ïî êàëèáðîâêå____ïîF ___P_______________4,54__________8,84 ___P_______________4,57__________8,86 ___P/10____________0,50__________5,57_____________0,45_ _________0,88 ___P/10___________0,47___________5,50_____________0,46_ _________0,89 ____R_____________37,48_________31,88 ____R_____________33,37_________32,21 ____R/10___________3,55___________8,07_____________3,75_ __________3,19 ____R/10____________3,59___________8,03____________3,34_ __________3,22 ____R/20___________1,61___________6,51_____________1,87_ __________1,59 ____R/20___________1,76___________6,53______________1,67 ___________1,61 Ñîâïàäåíèå ðåçóëüòàòîâ ñ îæèäàåìûìè çíà÷åíèÿìè òîæå íå èäåàëüíî, íî âñå îòíîñèòåëüíî. 3,59 ïðè îæèäàåìîì 3,34 âñå æå ëó÷ øå, ÷åì 8,03 ïðè îæèäàåìîì 3,22. Ðàçóìååòñÿ, ìîæíî âîçðàçèòü, ÷òî ðàçâåäåíèå ïðîá äåëàëîñü ôèçðàñòâîðîì (ïðàêòè÷åñêè âîäîé). Ñîãëàñåí.  ñâîå âðåìÿ ïðè òåñòèðîâàíèè íàáîðà ÿ ñìåøèâàë ïðîáû ñ ðàçíûìè çíà÷åíèÿìè (î÷åíü íèçêèõ íå áûëî). Ðåçóëüòàòû áûëè îæèäàåìûå. Íà ðàáîòå ýòè äàííûå, íàâåðíî, åñòü. Íî òî÷íî áåç îïòè÷åñêèõ ïëîòíîñòåé. Òîëüêî ðåçóëüòàò. Ïîïðîáóþ îáÿçàòåëüíî ïîâòîðèòü, êàê òîëüêî áóäåò ñûâîðîòêà ñ íèçêèì æåëåçîì. Ïîñ÷èòàþ ïî êàëèáðîâêå è ïî F. Åñòåñòâåííî, åñòü åùå îäíà ïðîáëåìà. ß åå íå îçâó÷èâàë. È ïîêà íå áóäó. |
#52
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Èòàê åñòü åùå äàííûå:
Äåëàåì ãðàôèê ñèíèé -ïî ôàêòîðó êðàñíûé - ðåãðåññèÿ (239.79*x-9.46) ôàêòè÷åñêèõ òî÷åê (ñèðåíåâûå) [Èçîáðàæåíèÿ äîñòóïíû òîëüêî çàðåãèñòðèðîâàííûì ïîëüçîâàòåëÿì] à òåïåðü âåñü äèàïàçîí èçìåðåíèÿ [Èçîáðàæåíèÿ äîñòóïíû òîëüêî çàðåãèñòðèðîâàííûì ïîëüçîâàòåëÿì] Îñòàëîñü âûÿñíèòü êàê ñåáÿ âåäåò íàáîð ïðè âûñîêèõ öèôðàõ (ðàñòâîð äëÿ ÎÆÑÑ íàïðèìåð). Âîçìîæíî ðåãðåññèÿ ïîìåíÿåòñÿ. Âíå çàâèñèìîñòè îò ýòîãî íàäî âûÿñíÿòü ïî÷åìó íàáëþäàåòñÿ òàêîå îòêëîíåíèå äàæå â íîðìàëüíîì äèàïàçîíå. Õîðîøî áû ïîñòàâèòü íà ïîëóàâòîìàòå â îäíîðàçîâûõ êþâåòàõ. |
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#53
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Òàê, êîëëåãè, ïîðà îòäåëÿòü ìóõ îò êîòëåò (èëè íàîáîðîò).
Ìåòîä ëèíåéíîé ðåãðåññèè, èñïîëüçóåìûé àâòîðîì òåìû äëÿ ðàñ÷åòîâ, ïîçâîëÿåò âûâåñòè ïðÿìóþ ëèíèþ, ìàêñèìàëüíî ñîîòâåòñòâóþùóþ ðÿäó óïîðÿäî÷åííûõ ïàð (Õ;Y) – â íàøåì ñëó÷àå êîíöåíòðàöèè æåëåçà Y è àáñîðáöèè ïðîáû Õ. Ýòî ìàòåìàòè÷åñêèé ïîäõîä, êîòîðûé ìîäåëèðóåò èäåàëüíóþ ëèíåéíóþ çàâèñèìîñòü Y îò Õ. Öåëü ìåòîäà ñîñòîèò â ìèíèìàëèçàöèè îáùåé êâàäðàòè÷íîé îøèáêè ìåæäó íàáëþäàþùèìèñÿ (èçìåðÿåìûìè) è ïðåäñêàçàííûìè çíà÷åíèÿìè. Èìåííî çäåñü êðîåòñÿ òàêòè÷åñêàÿ îøèáêà è ïîäìåíà ïîíÿòèé. Ìû èìååì ñèòóàöèþ, êîãäà ðåçóëüòàò ïàöèåíòà âûâîäèòñÿ íå íà îñíîâå èçìåðåíèÿ àáñîðáöèè è ïåðåñ÷åòà å¸ â êîíöåíòðàöèþ (ðåçóëüòàò èçìåðåíèÿ), à íà îñíîâå ðàñ÷åòà îæèäàåìîãî çíà÷åíèÿ, èäåàëüíî ñîîòâåòñòâóþùåãî äàííîé àáñîðáöèè ïðè íàéäåííîé êîððåëÿöèè. Òî, ÷òî îæèäàåìûå ðåçóëüòàòû ðàçâåäåíèé êàëèáðàòîðîâ è ïðîá ñîâïàäàþò ñ ÿêîáû èçìåðåííûìè (à ïî ôàêòó, ðàññ÷èòàííûìè ïî óðàâíåíèþ ëèíåéíîé ðåãðåññèè) ãîâîðèò ëèøü î òîì, ÷òî êîððåëÿöèîííàÿ çàâèñèìîñòü íàéäåíà âåðíî. Àëåêñàíäð, Âû îïðåäåëÿåòå ìàòåìàòè÷åñêîå îæèäàíèå ðåçóëüòàòà, à íå ñàì ðåçóëüòàò. È òî, ÷òî ìàòåìàòè÷åñêîå îæèäàíèå ñîâïàäàåò ñ òåì, ÷òî Âû îæèäàåòå, ïðîñòèòå çà òàâòîëîãèþ, ãîâîðèò ëèøü î Âàøèõ âåëèêîëåïíûõ ìàòåìàòè÷åñêèõ ñïîñîáíîñòÿõ, íî íèêàê íè î ëèíåéíîñòè ìåòîäèêè, íè î å¸ ÷óâñòâèòåëüíîñòè. Öåëü ëàáîðàòîðíîãî àíàëèçà – ÈÇÌÅÐÈÒÜ êîíöåíòðàöèþ àíàëèòà, à íå ðàññ÷èòàòü ìàêñèìàëüíî èäåàëüíîå îæèäàåìîå çíà÷åíèå. |
#54
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Çàõîòåëîñü ïðîñòî ïîó÷àñòâîâàòü â äèñêóññèè âîò ñ òàêîé ñòîðîíû: à êîãäà æåëåçî ìîæåò áûòü íóëåâûì íà ñàìîì äåëå ïðè ïðàâèëüíîì èçìåðåíèè? - ïðè ñëó÷àéíîé êîíòàìèíàöèè ÝÄÒÀ ïðè íåïðàâèëüíîì êðîâåçàáîðå:
Clin Chim Acta. 2002 Nov;325(1-2):105-11. The effect of EDTA contaminated in sera on laboratory data. Imafuku Y, Meguro S, Kanno K, Hiraki H, Nemoto U, Hata R, Takahashi K, Miura Y, Yoshida H. SourceDepartment of Clinical Laboratory Medicine, Fukushima Medical University School of Medicine, 1-Hikarigaoka, Fukushima 960-1247, Japan. BACKGROUND: We report two cases in which the data marked by low levels of serum iron (Fe) (negative value), low levels of serum calcium (Ca) and high levels of serum potassium (K) were inconsistent with their clinical states. Re-examination within 1 day showed that all the data were within or close to the reference intervals. These results could suggest contamination of ethylene diamine tetraacetate-dipotassium salt (K(2)EDTA) used in the blood collection tube for peripheral blood cell count in the tube for the serum. One of the mechanisms was suspected to be due to the backflow of evacuated blood mixed with K(2)EDTA into serum tube. MATERIALS AND METHODS: To analyze the influence of EDTA on routine and nonroutine laboratory tests, we performed routine examination using serum and EDTA plasma from healthy volunteers. RESULTS: We found a definite effect on iron, calcium and potassium and alkaline phosphatase, zinc sulfate turbidity test, ammonia, leucine aminopeptidase and CH50. We also found a definite effects on copper, angiotensin-converting enzyme (ACE), matrix metalloproteinase (MMP)-1, -3 and -9, tissue inhibitor of matrix metalloproteinase (TIMP)-1, hepatocyte growth factor (HGF), monoamine oxidase (MAO), vitamin B(12), ACTH and IL-6, though the mechanisms were not clear. CONCLUSIONS: Inappropriate blood collection can induced false biochemical data due to the contamination of EDTA.
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Èñêðåííå, Âàäèì Âàëåðüåâè÷. |
#55
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Ýòî áûëî ïîäòâåðæäåíî è â äð. ïóáëèêàöèÿõ:
Ann Clin Biochem. 2002 May;39(Pt 3):273-80. Effects of contamination of blood specimens with liquid potassium-EDTA anticoagulant. Davidson DF. SourceBiochemistry Department, Crosshouse Hospital, Kilmarmock, Scotland, UK. BACKGROUND: Use of the anticoagulant EDTA, in high-concentration liquid form, in blood collection tubes can lead to cross-contamination of routine biochemistry specimens. METHODS: In the present study, tests affected by EDTA in the sample were potassium, calcium, magnesium, unsaturated iron-binding capacity, bicarbonate, aspartate transaminase, alanine transaminase, lactate dehydrogenase, creatine kinase, alkaline phosphatase and amylase. The likely mechanisms are discussed. CONCLUSIONS: In the interests of best practice, the identification of subtle contamination of blood specimens for biochemical analysis requires a sensitive method for measurement of EDTA itself. äàííûé ôåíîìåí íåðåäêî âñòðå÷àåòñÿ â ñîâðåìåííîé ëàáîðàòîðèè îñîáåííî â ñëó÷àÿõ ñ ãèïåðêàëåìèåé è äàæå ïðåäëîæåíû âàðèàíòû êàê ïîïûòàòüñÿ èäåíòèôèöèðîâàòü äàííûå ïðîáû êðîâè â óñëîâèÿõ ëàáîðàòîðèè: Ann Clin Biochem. 2008 Nov;45(Pt 6):601-3. Spurious hyperkalaemia due to EDTA contamination: common and not always easy to identify. Cornes MP, Ford C, Gama R. SourceDepartment of Clinical Chemistry, New Cross Hospital, Wolverhampton, West Midlands WV10 0QP. BACKGROUND: To study the detection and prevalence of spurious hyperkalaemia due to potassium ethylenediaminetetra-acetic acid (kEDTA) contamination. METHODS: In a one-month prospective study, serum EDTA, zinc, calcium, magnesium concentrations and alkaline phosphatase activity were measured in samples with serum potassium >or=6.0 mmol/L. RESULTS: Twenty-eight out of 117 hyperkalaemic samples were contaminated with EDTA. Only serum zinc values below the reference range had 100% sensitivity for indicating EDTA contamination, but even at an optimal specificity of 89% at least 12 potentially genuine hyperkalaemic samples would be rejected. CONCLUSION: Spurious hyperkalaemia due to kEDTA contamination is common. Gross kEDTA contamination is obvious by marked unexpected hyperkalaemia, hypocalcaemia, hypomagnesaemia and hypozincaemia. Spurious hyperkalaemia due to low concentrations of kEDTA contamination can only be confidently detected by measurement of serum EDTA.
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Èñêðåííå, Âàäèì Âàëåðüåâè÷. |
#56
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 ïðèíöèïå ìîæåò áûòü - áåðóò îáû÷íî ñíà÷àëà ÝÄÒÀ, ïîòîì ñûâîðîòêó. Ìîæåò â êàêèõ-òî ñëó÷àÿõ íà èãîëêó ïîñëå ïðîêàëûâàíèÿ êðûøêè îñòàþòñÿ ñëåäû ÝÄÒÀ...
Òàê ìîæíî è ðàññìîòðåòü êþâåòû àíàëèçàòîðà - åñëè òàì áûëà ïëàçìà ñ ÝÄÒÀ (õîòü è ðåäêèé ìàòåðèàë, íî èíîãäà äåëàþò è èç òàêîé ïëàçìû). |
#57
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Öèòàòà:
Ïðèáîð èçìåðÿåò îïòè÷åñêóþ ïëîòíîñòü îáðàçöà (îáðàçöîâ) à íå êîíöåíòðàöèþ. Ïîòîì ðàññ÷èòûâàåò. Ïî ôàêòîðó èëè ïî êàëèáðîâêå, åñëè îíà áûëà ðàíåå ñäåëàíà. Íàø àíàëèçàòîð âåäåò ðàñ÷åò òàê, êàê ââåäåíî â äàííóþ ìåòîäèêó. Òî åñòü åñëè òàì óêàçàíî ïî ôàêòîðó - ðàñ÷åò ïî ôàêòîðó. Èëè åñëè óêàçàíà êàëèáðîâêà è îíà ïðîâåäåíà, - òî ðàñ÷åò ïî êàëèáðîâêå. Ëèáî òàê, ëèáî ýäàê. Íî àíàëèçàòîð ïîêàçûâàåò ïðîìåæóòî÷íûå äàííûå - îïòè÷åñêóþ ïëîòíîñòü îáðàçöîâ, òî åñòü, çíà÷åíèÿ, íà îñíîâàíèè êîòîðûõ îí ïðîâîäèò ðàñ÷åò. Ïî ýòîìó ÿ, ïðîâåäÿ èçìåðåíèå ñåðèè îáðàçöîâ, ñðåäè êîòîðûõ åñòü êàëèáðàòîð (30) è âîäà (0) ìîãó ðàññ÷èòàòü êîíöåíòðàöèè îñòàëüíûõ ïðîá ïî ôàêòîðó (ïîñ÷èòàâ åãî) èëè ïî êàëèáðîâêå (òîæå ïîñ÷èòàâ óðàâíåíèå ðåãðåññèè (AlexT, ÿ ïîìíþ Âàøè ñëîâà ïðî 0)). Àíàëèçàòîð ðàññ÷èòûâàë áû òî÷íî òàê æå, òîëüêî ïðèøëîñü ïðîâîäèòü èçìåðåíèå îáðàçöîâ äâàæäû, ñíà÷àëà ïî ôàêòîðó, çàòåì ïî êàëèáðîâêå. ðàçóìååòñÿ ïðîâåäÿ ñíà÷àëà êàëèáðîâêó è ïîëó÷èâ ôàêòîð. È àíàëèçàòîð íå ïîâòîðèò òî÷íî òåõ æå ðåçóëüòàòîâ îïòè÷åñêèõ ïëîòíîñòåé - îí íå èäåàëåí. Òî åñòü ÿ ïðîâåë ðàñ÷åòû, êàê áóäòî ðàáîòàë âðó÷íóþ íà ÔÝÊå èëè ÑÔå  ôàéëå Exel åñòü âñå ðàñ÷åòû, ôîðìóëû â ÿ÷åéêàõ. ß èñïîëüçîâàë òåðìèí îæèäàåìûå ðåçóëüòàòû. Íó íå ïðèäóìàë êàê íàçâàòü. Åñëè ìû ðàçâîäèì îáðàçåö â äâà ðàçà, òî îæèäàåì, ÷òî ïðè èçìåðåíèè ðåçóëüòàò (êîíöåíòðàöèÿ) â íåì áóäåò ìåíüøå, ÷åì â èñõîäíîì â äâà ðàçà. Ýòî, êîíå÷íî, èäåàë. Íå çíàþ ÷òî åùå ñêàçàòü... Ó ìåíÿ ñëîâ íåò, åñëè ÷åñòíî. |
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À ÿ ïîïðîáóþ åùå ðàç.
ß ñåé÷àñ áóäó ïèñàòü îá î÷åâèäíûõ âåùàõ, íî íå äëÿ ïîó÷àíèÿ, à äëÿ êîíêðåòèçàöèè.
 îñíîâå êîëîðèìåòðè÷åñêèõ òåñòîâ ëåæèò çàâèñèìîñòü àáñîðáöèè ïðîáû îò êîíöåíòðàöèè àíàëèòà, à íå íàîáîðîò. Ýòî ïîíÿòíî. Êîíöåíòðàöèÿ àíàëèòà â êîíêðåòíîé ïðîáå – âåëè÷èíà ïîñòîÿííàÿ; àáñîðáöèÿ ïðîáû – âåëè÷èíà ïåðåìåííàÿ (èçìåðÿÿ ïðîáó 10 ðàç ìû íèêîãäà íå ïîëó÷èì àáñîëþòíî îäèíàêîâóþ àáñîðáöèþ, ïîñêîëüêó âñåãäà áóäåò ïðèñóòñòâîâàòü íåêàÿ ïîãðåøíîñòü, ñâÿçàííàÿ ñ íåòî÷íîñòüþ äîçèðîâàíèÿ, ôîòîìåòðèè, ÷èñòîòîé êþâåòû è ïðî÷èìè âëèÿþùèìè ôàêòîðàìè – ýòî âñåì òîæå ïîíÿòíî).  ôîðìóëå Rez = k*DA – b óâàæàåìûé êîëëåãà ïðèñâàèâàåò àáñîðáöèè õàðàêòåðèñòèêè ïîñòîÿííîé âåëè÷èíû, à êîíöåíòðàöèè – ïåðåìåííîé, à ýòî ìåòîäîëîãè÷åñêè íåâåðíûé ïîäõîä. Åñëè áû èçíà÷àëüíî ôîðìóëà ïîäàâàëàñü â âèäå Rez = k*õ, ãäå k = 30.0/0.1327 = 226.073, à õ=DA-àáñ.õîëîñòîé ïðîáû (âîäû), íå âîçíèêëî áû íèêàêèõ íåäîðàçóìåíèé. (Ìîæíî ëè ñóììèðîâàòü àïåëüñèíû è ïîìèäîðû? À óìíîæàòü êîéêè íà äíè? À äåëèòü íà 0? Âñå ìîæíî, íî ýòî çàâèñèò îò öåëè ìàòåìàòè÷åñêèõ èçûñêàíèé.) Òî åñòü, ïðåîáðàçóÿ âîò ýòî óðàâíåíèå Öèòàòà:
Rez = k*(DA – b/k), ãäå b/k åñòü ôàêòè÷åñêè àáñîðáöèÿ õîëîñòîé ïðîáû (â ïðèìåðå DA âîäû - 0.0266), ìû ïîëó÷èì òî, ÷òî òðåáóåòñÿ ïî ìåòîäèêå Rez= ΔÀáñ.ïð*F, ãäå F= k, à ΔÀáñ.ïð= DAïð.- DA âîäû. To AlexPAR Öèòàòà:
Ëèíåéíîñòü ïðîâåðÿåì ñ èñïîëüçîâàíèåì ðàçâåäåíèé ëþáîãî ìàòåðèàëà ñ èçâåñòíîé êîíöåíòðàöèåé è áîãàòîãî àðñåíàëà ñòàòèñòè÷åñêèõ ìåòîäîâ. Öèòàòà:
Âîïðîñ â òîì, êàê ýòî ïðîèñõîäèò â àíàëèçàòîðå. Åñëè âñå àáñîðáöèè àâòîìàòîì ðåãèñòðèðóþòñÿ óæå ñ âû÷åòîì õîëîñòîé ïðîáû, äîáàâëÿòü åùå îäíó îáíóëÿþùóþ ïðîáó ñ âîäîé íå ïðàâèëüíî. Åñëè íåò, ïðîáà ñ âîäîé ðàññìàòðèâàåòñÿ êàê õîëîñòàÿ è ïðàâîìåðíà. Ïî âîäå ó ìåíÿ äâà âîïðîñà. Ïî÷åìó áëàíêè âîäû âûøå, ÷åì áëàíêè êàëèáðàòîðà. Ïî÷åìó â âîäå â ïðîöåññå ðåàêöèè èäåò ïðèðîñò àáñîðáöèè, åãî áûòü íå äîëæíî, åñëè îíà íå ñîäåðæèò æåëåçî. È îòñþäà äâà âûâîäà. Íóæíî óáåäèòüñÿ â êà÷åñòâå âîäû, ïðåæäå ÷åì èñïîëüçîâàòü å¸ äëÿ õîëîñòîé ïðîáû. Íóæíî óáåäèòüñÿ â ÷èñòîòå êþâåò è îòñóòñòâèè ñóùåñòâåííîé ïîãðåøíîñòè èçìåðåíèÿ (ìåíÿòü ïîçèöèè ïðîá, íàïðèìåð, ÷òîá íå ïîïàäàëè â îäíè è òå æå ÿ÷åéêè, è íàáëþäàòü çà èçìåíåíèÿìè àáñîðáöèè). Äðóãèìè ñëîâàìè, ïðåæäå ÷åì âû÷èñëÿòü êàëèáðîâêó, íóæíî óáåäèòüñÿ â îòñóòñòâèè çíà÷èìûõ ïîãðåøíîñòåé íà êàæäîì ýòàïå èçìåðåíèÿ. È ïîñëåäíåå. Åñëè ìåòîäèêà ïðîèçâîäèòåëÿ äåéñòâèòåëüíî îáëàäàåò òàêîé ÷óâñòâèòåëüíîñòüþ, êàêóþ ïîëó÷èë àâòîð òåìû, ïî÷åìó ýòî íå çàÿâëåíî ïðîèçâîäèòåëåì, ýòî æå îãðîìíûé ïëþñ? Çà Åðàëàø ñïàñèáî, ñìåøíî. |
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ß õî÷ó îáðàòèòü âíèìàíèå íà íàøè ýêñïåðèìåíòàëüíûå äàííûå :
ñèíèé -ïî ôàêòîðó êðàñíûé - ðåãðåññèÿ (239.79*x-9.46) ôàêòè÷åñêèõ òî÷åê (ñèðåíåâûå) [Èçîáðàæåíèÿ äîñòóïíû òîëüêî çàðåãèñòðèðîâàííûì ïîëüçîâàòåëÿì] Îíè íå ñîãëàñóþòñÿ ñ ãèïîòåçîé , ÷òî ñìåùåíèå (b=0) íåçíà÷èìî. Íóëåâàÿ ïðîáà òóò âîîáùå íå ïðèíèìàëà ó÷àñòèå â ðàññ÷åòàõ. |
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Äà, òóò ìû êàê-òî óïóñòèëè 2 ìîìåíòà:
1. Âûøåïðèâåäåííûå ãðàôèêè - ïîñòðîåíû íå ñîâñåì òàê êàê ïðèíÿòî ñòðîèòü êàëèáðîâêó. Ó íàñ y-êîíöåíòðàöèÿ, x - îïòè÷. ïëîòíîñòü. Åñëè âñå ñäåëàòü êàê ïðèíÿòî, ïîëó÷èì âîò òàêîé ãðàôèê (Y-ÎÏ, Õ-Êîíö.): [Èçîáðàæåíèÿ äîñòóïíû òîëüêî çàðåãèñòðèðîâàííûì ïîëüçîâàòåëÿì] Óðàâíåíèå ðåãðåññèè êàëèáðîâî÷íîé êðèâîé (ÎÏèññë=ÎÏïðîáû-ÎÏáë): [ÎÏ]= 0.00452*[Êîíöåíòðàöèÿ}+0.0315 Îòñþäà [êîíöåíòðàöèÿ èññëåäóåìûõ ïðîá]=([ÎÏèññë.] - 0.0315)/0.00452 = = 221.3*[ÎÏèññë]-6.96 Åñëè èç âñåõ ïëîòíîñòåé âû÷åñòü õîëîñòóþ ïðîáó (0), òîæå íè÷åãî íå ïîìåíÿåòñÿ - íàêëîí îñòàíåòñÿ òàêèì æå, ò.å 221 à íå 185 2. Öèòàòà:
1.Ðó÷íîå îïðåäåëåíèå äåëàëîñü ïî ôàêòîðó è íå èññëåäîâàëèñü ðàçâåäåíèÿ . Òîãäà ýòîãî ïðîñòî íå áûëî âèäíî. 2. Ðàçâåäåíèÿ äåëàëèñü, íî ðåçóëüòàòû ñîâïàëè ñ îæèäàåìûì ïî ìåòîäèêå ôàêòîðîì. Òîãäà íàáîð íå ðàáîòàåò òîëüêî íà äàííîì àâòîìàòå. |