R: Producing multiple plots (ggplot, geom_point) from a single CSV with multiple subcategories
something like this might work:

library(plyr)

# initialize All_Data around here

dlply(All_Data, 'Identifier', function(dataSubset) {
  g &lt;- ggplot(dataSubset) + geom_point(mapping =aes(SampleDate, Total.Result)) + ylim(0,20000)
  file_name &lt;- paste0("Scatter_", unique(dataSubset$Identifier), ".tiff", sep="")
  ggsave(file_name,g)
})


(I didn't test it)