95 



not represent a true reflection of the [H"^] ion or [OH~] ion concentration. The 



indicated pH, amount of acid or base added, and concentration of acid or base to 

 a 20 mL aliquot of 12 |ig/nL methanolic L-lactic acid were: pH 0.45 from addition 

 of 50 p,L 12M HCl, pH 3.05 from the unadjusted control, pH 7.10 from addition of 

 200 \iL of ION NaOH, pH 11.80 from addition of 250 ^L ION NaOH, and pH 13.10 

 from addition of 1 mL ION NaOH. It was observed that a white precipitate was 

 present in the most basic solution. A 100 nL aliquot from each of the 20 mL stock 

 solutions were placed on petri dishes and dried. The sample-containing petri dishes 

 were then tested for attraction versus a control petri dish in the olfactometer. 



Esters were tested in the olfactometer in the same fashion as the L-lactic acid 

 solutions; however, the sample preparation differed. Sampling consisted of 100 |aL 

 each of lactic acid, methyl lactate, ethyl lactate, and ethyl isovalerate dried on 

 separate petri dishes. A second series of experiments was conducted in which a 100 

 jiL spike of 10% HCl was mixed with 100 ^iL of each sample and allowed to dry on 

 the petri dish prior to analysis. 



Methanolic L-lactic acid solutions and methyl lactate solutions were analyzed 

 mass spectrometrically. Solutions consisting of 205 ng/p,L L-lactic acid plus 400 

 ng/jiL NaOH, methanolic 120 ng/^iL L-lactic acid solutions (spiked with 12M HCl 

 and ION NaOH to give indicated pH values of 3.05 and 11.80, respectively), and a 

 214 ng/|j.L standard methyl lactate solution in methanol were analyzed. Injections 

 of 0.5 p.L of each of these solutions were employed; however, the GC conditions 

 differed. Solutions containing 205 ng/[a.L L-lactic acid (with 400 ng/^iL NaOH) and 



