Yes! Raw material purity information is recorded on the certificate of analysis. Restek\u2019s Quality Control (QC) lab confirms the chemical identity and purity of mixture components and solvents using two or more of the following techniques: GC-FID, HPLC, GC-ECD, GC-MS, LC-MS, refractive index, and melting point. Compounds with a listed purity of less than 99% have been weight corrected to compensate for the presence of extraneous impurities in the compound, inorganic moieties (salts, hydrates, etc.), and organic moieties (typically the functional group of a derivatized compound). To better illustrate these scenarios, the following examples will explain the process we apply:<\/p>\n\n\n\n
Compound A is tested and found to contain a 2% impurity (compound B). That is, the purity of compound A is 98%. So, if 100 mg is weighed out, the material will contain 98 mg of compound A and 2 mg of compound B. Adding 100 mL of solvent will produce a concentration of 980 \u00b5g\/mL for compound A, not the desired 1,000 \u00b5g\/mL. To reach a concentration of 1,000 \u00b5g\/mL for compound A, Restek chemists apply a correction factor of 0.98 to obtain the final concentration:<\/p>\n\n\n\n
100 mg \u00f7 0.98 = 102 mg<\/p>\n\n\n\n
(102 mg \u00f7 100 mL) x 1,000 = 1,020 \u00b5g\/mL x 0.98 = 1,000 \u00b5g\/mL compound A<\/p>\n\n\n\n
Compound A is the hydrochloride salt of an organic amine. If the molecular weight of compound A is 100 AMU, then the molecular weight of the parent compound (organic moiety) would be 63.5 AMU\u2014molecular weight of compound A minus molecular weight of HCl. The ratio of organic moiety to inorganic moiety would be:<\/p>\n\n\n\n
63.5 \u00f7 100 = 0.635<\/p>\n\n\n\n
If 100 mg is weighed out, the material will contain 63.5 mg of the parent compound and 36.5 mg of HCl. Adding 100 mL of solvent will produce a concentration of 635 \u00b5g\/mL for the parent compound, not the desired 1,000 \u00b5g\/mL. To reach a concentration of 1,000 \u00b5g\/mL for the parent compound, Restek chemists apply a correction factor of 0.635 to obtain the final concentration:<\/p>\n\n\n\n
100 mg \u00f7 0.635 = 157.5 mg<\/p>\n\n\n\n
(157.5 mg \u00f7 100 mL) x 1,000 = 1,575 \u00b5g\/mL x 0.635 = 1,000 \u00b5g\/mL parent compound<\/p>\n\n\n\n
Compound A is the dinitrophenylhydrazone (DNPH) derivative of a carbonyl compound. If the molecular weight of compound A is 250 AMU, then the molecular weight of the parent compound (carbonyl moiety) would be 70 AMU\u2014molecular weight of compound A minus molecular weight of DNPH moiety. The ratio of carbonyl moiety to carbonyl DNPH moiety would be:<\/p>\n\n\n\n
70 \u00f7 250 = 0.28<\/p>\n\n\n\n
If 100 mg is weighed out, the material will contain 28 mg of the parent compound and 72 mg of DNPH. Adding 100 mL of solvent will produce a concentration of 280 \u00b5g\/mL for the parent compound, not the desired 1,000 \u00b5g\/mL. To reach a concentration of 1,000 \u00b5g\/mL for the parent compound, Restek chemists apply a correction factor of 0.28 to obtain the final concentration:<\/p>\n\n\n\n
100 mg \u00f7 0.28 = 357.1 mg<\/p>\n\n\n\n
(357.1 mg \u00f7 100 mL) x 1,000 = 3,571 \u00b5g\/mL x 0.28 = 1,000 \u00b5g\/mL parent compound<\/p>\n\n\n\n