multiple choices

20問 • 7ヶ月前

問題一覧

You are designing an analytical method for detecting a trace toxin in drinking water. Your primary goal is to ensure the data supports public health decisions. What is the first step in developing quality specifications?

C. Determine the use objective

A colleague evaluates accuracy by comparing results from a certified reference material (CRM). Why is this an appropriate approach?

C. CRMs have known analyte values

You test a method using 10 replicates under the same conditions by the same analyst in one session. Which precision category applies?

B. Intra-assay precision

If the slope of your calibration curve is very low, what does it suggest about the method's sensitivity?

C. It is poorly sensitive

A method has a detection limit of 0.5 ng/mL and a reporting limit of 5 ng/mL. A result of 3 ng/mL should be reported as:

C. Not detected

If you notice 7 consecutive data points all below the center line on a control chart, what action should be taken?

B. Replace reagents

A newly developed method is being transferred between laboratories. Which validation parameter is most critical to assess?

B. Ruggedness

A method consistently identifies the analyte in the presence of closely related compounds. Which parameter does this illustrate?

B. Selectivity

What is the primary reason for performing sample homogenization before analysis?

C. To ensure uniform distribution of analytes in the sample

How does the variance of sampling operations affect overall variance in analysis?

A. It directly contributes to the overall variance in analysis

What is the relationship between the size of the sieve and the particle size it retains?

B. Smaller sieves retain smaller particles

The sampling technique is very important when analyzing a large area or vast amounts of material because you cannot analyze everything. When preparing a composite sample, a chemist would each.

B. take representative samples from various areas of the bulk samples and combine them for analysis.

A detector response may be different for analytes with equal concentrations; therefore

B. A calibration curve must be constructed.

You have taken several sediment samples from the bottom of the Great Lakes and wish to analyze the material for the presence of polycyclic aromatic hydrocarbons, class of compounds with many Environmental Protection Agency (EPA) priority pollutants. Which calibration method is most appropriate for the analysis?

A.method of standard addition

Which of the following is true regarding a blank used in an analytical analysis?

C. A reagent blank is the same as a method blank; that is, it has been taken through all of the steps of the analytical procedure.

The result tends to cluster symmetrically to the average value if

A. If the errors are purely random

Which of the following is true regarding the matrix effect?

C. The matrix effect may be minimized by using the method of standard additions.

What is the relation between the standard deviation and the precision of a procedure?

B.There is no necessary relationship between standard deviation and accuracy.

In the Gaussian curve, how the size of the confidence interval for the mean is influenced by the standard deviation o? (all the other factors are constant):

A. as the standard deviation, o increases, the confidence interval increases.

This method of standardization can compensate for certain types of errors if those influence both the analyte and the reference species to the same proportional extent. Because of the difficulty in finding an appropriate reference species, this method is not as commonly used as some other petroleum-compensating methods.

D. Use of internal standards

biochem

velante · 99問 · 1年前

biochem