As you complete these problems COPY the results into your lab notebook for use d

Question

As you complete these problems COPY the results into your lab notebook for use during your lab You need to create 5 serial Dilutions of Creatinine standards with a total volume of 1 mL each. You are provided with a 25 mg/dL stock Creatinine solution. The first concentration required is provided in the table below. Create a series of dilutions by cutting the concentration by 40% each time Complete the following table based on the use of the information above to make the following PPM concentrations of Creatinine. (1 mL of total volume is used) (Give answers to 3 sigfigs): Volume Volume (HL) Creatinine Needed (Serial Dilution) Saline buffer (uL)Needed Dilution # [Creatinine](mg/dL)[Creatinine](PPM) Dilution 1 24.5 245 980 20 Dilution 2 14.7 147 588 412 Dilution 3 8.82 88.2 353 647 Dilution 4 5.29 212 1212 788 Dilution 5 3.17 127 X 127 873

Explanation / Answer

In 1st table, the ppm of creatinine is calculated by multiplying creatinine (mg/dl) by 10.

Volume (microlitres) is calculated from creatinine concentration and concentration of stock solution by using formula M1V1 = M2V2

For example for 24.5 mg/dl, total volume needed is 1 ml = 1000 microlitres

So, M1 = 24.5 mg/dl, V1 = 1000 microlitres

M2 = 25.0 mg/dl, V2 = ?

By puuting these values in the formula, we get V2 = 980 microlitres

Similarly for other cases, we can calculate.

Volume saline buffer = 1000-V2

For table 2, to convert % T to absorbance, formula used is A = 2- log (% T)

For, % T = 6.92, A = 2- log(6.92) = 2-0.8401 = 1.1599

Similary A can be calculated from other %T.

For Table 3, For 1st dilution, [BUN] = 53

Its given that next concentration is half of this, So, for 2nd dilution, [BUN] = 53/2 = 26.5

Similarly we did half of every previous concentration.

the ppm of BUN is calculated by multiplying [BUN] (mg/dl) by 10.

Volume (microlitres) is calculated from BUN concentration and concentration of stock solution by using formula M1V1 = M2V2

For example for 53 mg/dl, total volume needed is 1 ml = 1000 microlitres

So, M1 = 53 mg/dl, V1 = 1000 microlitres

Stock solution, M2 = 60 mg/dl, V2 = ?

By puuting these values in the formula, we get V2 = 883 microlitres

Similarly for other cases, we can calculate.

Volume saline buffer = 1000-V2

Dilution [Creatinine] (mg/dl) [Creatinine] (PPM) Volume(µl) Creatinine Needed (serial dilution) Volume Saline buffer (µl) needed 1 24.5 245 980 20 2 14.7 147 588 412 3 8.82 88.2 353 647 4 5.29 52.9 212 788 5 3.17 31.7 127 873 Solution % T Absorbance 1 6.92 1.1599 2 26.2 0.5817 3 51.1 0.2916 4 71.4 0.1463 5 84.9 0.0711 6 91.9 0.0367 Dilution [BUN] (mg/dl) [BUN] (PPM) Volume(µl) BUN Needed (serial dilution) Colume Saline buffer (µl) needed 1 53 530 883 117 2 26.5 265 442 558 3 13.3 133 222 778 4 6.63 66.3 111 889 5 3.31 33.1 55.2 945 6 1.66 16.6 27.7 97

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.