Table 1.
Pipetting scheme to prepare the calibration line of the DL-2-HG for the EISA method.
| Calibration points | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
| |||||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | |
|
| |||||||||
| Concentration (μmol/L) per DL-2-HG enantiomer | 0.5 | 1.25 | 2.5 | 5 | 7.5 | 10 | 20 | 50 | 100 |
|
| |||||||||
| Concentration (μmol/L) of the stock solutions used for spikinga | 2 | 200 | 200 | 200 | 200 | 200 | 200 | 200 | 200 |
|
| |||||||||
| Volume (μL) of stock solution addedb | 50 | 1.25 | 2.5 | 5 | 7.5 | 10 | 20 | 50 | 100 |
|
| |||||||||
| Volume (μL) of 1 mmol/L IS solution addeda,b | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 |
|
| |||||||||
| Volume (μL) of 10 mmol/L sodium lactate solution addedb | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 |
|
| |||||||||
| Volume (μL) of methanol added | 200 | 200 | 200 | 200 | 200 | 200 | 200 | 200 | 200 |
a
The concentration depicted here is the sum of both enantiomers.
b
In case volumes lower than 20 μL cannot be accurately taken, use less concentrated stock solutions so that larger volumes of the corresponding aliquots can be used.