Abstract

Monoprotic

\(F = \frac {H}{H+KD}\)

Mydata <- read.csv("data for R.R monoprotic") 

pH <- Mydata$pH 

volume <- Mydata$Vol 

length(volume) 
## [1] 27
length(pH) 
## [1] 27
volume 
##  [1]  0.0  1.0  2.0  3.0  4.0  5.0  6.0  7.0  8.0  9.0 10.0 11.0 12.0 13.0 14.0
## [16] 15.0 16.0 17.0 18.0 19.0 20.0 21.0 22.0 23.0 23.5 23.8 24.0
pH 
##  [1] 3.510 3.635 3.811 3.976 4.090 4.169 4.260 4.343 4.409 4.470 4.550 4.610
## [13] 4.674 4.734 4.787 4.853 4.917 4.980 5.060 5.153 5.230 5.323 5.440 5.576
## [25] 5.630 5.685 5.721
plot(volume,pH,main = "Titration curved for Trail 1", xlab = "volume of NaOH", ylab = "pH") 

# Binding Curve from Titration data 

H <- 10^-(pH) 

CB <- 0.01 # base 

Vadd <- volume 

Vini <- 25  # initial volume of acid 

Vend <-  20.0 # estimated 

# fraction bound = 1 - (CB * Vadd + [H+] x (Vini + Vadd) ] / (CB * Vend) 

fb <- 1 - (CB* Vadd + H *(Vini + Vadd))/(CB * Vend) 

plot(pH,fb,main = "Binding Curve",xlab = "pH",ylab = "Fraction Bound") 

library(nls2)      
## Loading required package: proto
fit <- nls(fb ~ H/(CB+H), start=c(CB=0.01)) 

summary(fit) 
## 
## Formula: fb ~ H/(CB + H)
## 
## Parameters:
##     Estimate Std. Error t value Pr(>|t|)    
## CB 3.536e-05  4.715e-06   7.499 5.82e-08 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.1256 on 26 degrees of freedom
## 
## Number of iterations to convergence: 12 
## Achieved convergence tolerance: 9.494e-06
lines(pH,predict(fit), col="red")