Chapter 4
Appendix A
Thiram solution
The contaminant solutions are made with Thiram diluted in water.
103 mg of Thiram are put in 10,328 g of acetone: since Thiram is not dissolved in water at high concentrations, acetone has been used as a starting point.
In this fashion, knowing acetone density as 784 kg/m3, i.e. 784 g/L, i.e.
0.784 g/cm3 and Thiram density as 1.29 g/cm3, the concentration of the just prepared solution can be understood. The total volume of the solution V is:
V = 0.103g
1.29g/cm3 + 10.328g
0.784g/cm3 = 13.25331cm3 = 13.25331mL (A.1) knowing the relationships 1 dm3=1 L and 1 cm3 = 1 mL.
In order to understand how much is the concentration, it’s known 103 mg of the solute are diluted in a total volume of 13.25331 mL and the Thiram has a molecular weight of 240.4329 g/mol, so the total concentration C is:
C = 1
0, 784g/mL· 103 · 10−3g
240.4329g/mol· 1
13.25331 · 10−3L·103 = 41.303mM (A.2) In reality this is the molality, since we have mol/g, but anyway is a mea-sure of concentration of moles: 50 µL of the solution are taken, which is 103mg/13.25331mL · 0.05mL = 0.38852mg and they’re dissolved with water in order to achieve a concentration of 50 µM.
Thanks to the excel file 1, it’s needed 0.0324 L of purified water, in which 0.38852 mg are dissolved, in order to achieve a concentration of 50 µM. So from here lots of samples are prepared with different concentrations: the
1Molar converter.xls, Appendix B
minimum to be achieved is 100 pM.
6 mL of the solution 50 µM are taken and diluted with 24 mL of purified water (MilliQ) in a 5:1 ratio, in fact the total of the solution is 30 mL: 1 part is of the 50 µM solution, 4 parts are of water. In this way the achieved concentration is 1/5 of the starting one (which was 50 µM), i.e. 10 µM.
Then the next step is to achieve 10 µM, which is 1/10 of the just obtained concentration. In this fashion 4 mL of 10 µM solution are taken and diluted with 36 mL of MilliQ, obtaining a total solution of 40 mL composed by 1 part of the 10 µM solution and 9 parts of purified water.
The next steps are sum-up on the Table A:
starting solution [mL] water [mL] achieved concentration [M]
50 µL of 41.303 mM 32.4 mL 50 µM
6 mL of 50 µM 24 mL 10 µM
4 mL of 10 µM 36 mL 1 µM
15 mL of 1 µM 15 mL 500 nM
6 mL of 500 nM 24 mL 100 nM
10 mL of 100 nM 10 mL 50 nM
6 mL of 50 nM 24 mL 10 nM
10 mL of 10 nM 10 mL 5 nM
6 mL of 5 nM 24 mL 1 nM
10 mL of 1 nM 10 mL 500 pM
6 mL of 500 pM 24 mL 100 pM
Appendix B
Molar Converter
For the conversion of molar to ppb (or vice versa) it has been used an excel file where the inputs to insert are:
• Desired Concentration C (µM);
• Molecular Weight of the solute MW (g/mol);
• Known Density of the solution D (g/mL), usually is =1 because the solute is dissolved in water;
• volume of the solution V (L);
and the outputs will be the ppm and the ppb. The calculation is:
ppm = D ·V · C · M W
V · 103 = D · C · M W/103 (B.1)
ppb = 103· ppm (B.2)
For the opposite case, when the ppb is the first input (instead of C), the concentration C (µM) can be calculated as well:
C = 1
D · ppm 103 /M W
/V
· 106 (B.3)
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Acknowledgments
I would like to conclude this work with many thanks to everyone who sup-ported me in those years, from the very beginning of the Politecnico’s years until now.
First of all, I would like to remember my professor Davide Janner who helps me in doing this work, following me in laboratory experiences and gave to me lots of advice. A special thank goes to Elisa Muzi e Diego Pugliese, who helps me in understanding how to move in laboratories and also how to obtain good results with an high level of confidence.
Thanks to my mother Maria Maddalena, to my father Giorgio and to my sister Francesca, without whom I would not be here, they gave me support under all the aspects and help me to follow my dream to become an engineer.
Many thanks to all my friends, Box, Vik and Doc to be part of the GNE group, thanks for all the FIFA matches hoping that these traditions will re-main in time, thanks for all the alcool drunk in Birroteca and good time spent together.
Thanks to my always friend Giulia, with whom I grow up and with whom I want to spend lots of time: thank you for all the funny things done together.
Thanks to my Sicily friends, Marco e Salvo, thank you to introduce me to all the good vices to enjoy life. FIFA traditions must remain also for you (Marco returns back to your FIFA level please).
Thanks to all the Bamboo family, in random order Marco, Pistid e Si-mona, Dotola, Buva e Matte, Alessandra, Ilaria.