Chemistry Jeopardy. Method valida'on QA/QC. Internal Standard

Transcription

1 Chemistry Jeopardy Calibra'on QA/QC 1 QA/QC 2 Method valida'on Internal Standard

2 200 When would you select to use the standard addi4on method rather than a calibra4on curve? Matrix effects

3 400 When would you select a calibra4on curve instead of standard addi4on? Easier, faster No matrix effects

4 600 Calculate the concentra4on protein for A= 0.73, using the calibra4on curve below, with the formula: A= [protein] Outside calibra4on curve, can t use the data!

5 800 Which of the following is the largest for a typical instrument: Dynamic range Linear range Range Dynamic range- this is the range of concentra4on that generates a measurable response.

6 1000 Arrange the following in the proper order: A: use equa4on of line of best fit to determine the concentra4on of unknowns. B: subtract the average blank absorbance from the measurements. C: Prepare a series of standards of known concentra4on and measure the absorbance. D: make a graph of absorbance vs concentra4on C, B, D, A

7 200 Which of the following are NOT concerns of quality assurance: Keeping the method right Ge_ng the right data Ge_ng the data right Keeping the data right Keeping the method right

8 400 Clarifying and communica4ng what you will use the data for are: Use objec4ves Specifica4ons Selec4vity concerns Method valida4on concerns Use objec4ves This helps you decide how good your data need to be. Which is key in the next step of outlining specifica4ons.

9 600 What data are ploded on a control plot? Control plots are used to plot measurements of a known standard. It is used to visually demonstrate that the method is behaving as expected.

10 800 Specifica4ons may include which of the following: Sampling requirements Accuracy and precision Rate of false results Selec4vity Sensi4vity Acceptable blank values Recovery of for4fica4on Calibra4on checks Quality control samples All of these

11 1000 When submi_ng samples to an external lab for analysis, it is good prac4ce to submit a cer4fied reference material as an unknown. Performance test samples. What is this called?

12 200 You are sampling water. Aher collec4ng your sample, you sample a bodle of dis4lled water you brought with you to the field. What type of blank is this? Field blank

13 400 Aher dilu4ng my samples in 2% nitric acid for analysis, I remove an aliquot of the acid for analysis. Reagent blank What type of blank is this?

14 600 Which type of blank is used to correct absorbance measurements? Method blank

15 800 During an ICP- MS analysis run to examine trace metals extracted from mine tailings, I follow the following. Aher every tenth sample, I reanalyze a blank and preform a by analyzing a known sample. During an ICP- MS analysis run to examine trace metals extracted from mine tailings, I follow the following Standard Opera4ng Procedure (SOP). Aher every tenth sample, I reanalyze a blank and preform a calibra4on check by analyzing a known sample.

16 1000 At the end of every ICP- MS analysis run to examine trace metals extracted from mine tailings, I check the of my measurements by analyzing a NIST standard. Accuracy; replicate In order to assess the precision of each measurement, I also run samples.

17 200 Method valida4on incudes: Specificity Linearity Accuracy Precision Range Limit of detec4on Limit of quan4fica4on robustness All

18 400 Accuracy can be assessed using which the following: Analyzing blanks Cer4fied reference material Calibra4on curves Accuracy can be assessed: 1. Analysis of a cer4fied reference material 2. comparing results of different methods 3. Analyzing a spiked blank with the same matrix 4. Using standard addi4on

19 600 How is linearity most commonly measured? Least squares analysis Measured by r- squared. And what metric is used to quan4fy it?

20 800 When baseline separa4on is not achieved between peaks from similar analytes in your samples, what method valida4on principle is being violated? specificity

21 1000 State each of the following in terms of measured blank signal and standard devia4on : Signal detec4on Quan4fica4on limit Detec4on limit Signal detec4on= blank ave + 3s blank Quan4fica4on limit 10s blank /m Detec4on limit 3s blank /m

22 200 An internal standard involves: The addi4on of more analyte The addi4on of a substance other than the analyte recalibra4on between each measurement None of these The addi4on of a substance other than the analyte

23 400 An internal standard is likely used a. In chromatography or separa4ons b. In UV- Vis experiments c. Instead of a calibra4on curve d. to account for slight varia4ons in flow that might shih the analyte peak e. To account for sample lost during sample prepara4on In chromatography or separa4ons to account for slight varia4ons in flow that might shih the analyte peak To account for sample lost during sample prepara4on All but B and C

24 600 Which are required for internal standards: 1. Not contained in the sample matrix 2. Can be added in exact amounts 3. Is the same as the analyte 4. Behaves similar to analyte 5. Has rela4vely the same detector response over range measured All but 3

25 800 The area of the analyte and internal standard peaks are 450 and 380, respec4vely and F= 4. If the internal standard concentra4on is known to be 536 ppm, what is the concentra4on of the analyte in solu4on? ppm

26 1000