Improved tandem mass spectrometry (MS/MS) derivatized method for the detection of tyrosinemia type I, amino acids and acylcarnitine disorders using a single extraction process.

Abstract

BACKGROUND:

Succinylacetone (SUAC), a specific marker for tyrosinemia type I (Tyr I) cannot be detected by the routine LC-MS/MS screening of amino acids (AA) and acylcarnitines (AC) in newborns. The current derivatized methods require double extraction of newborn dried blood spots (DBS); one for AA and AC and the second for SUAC from the blood spot left after the first extraction. We have developed a method in which AA, AC and SUAC are extracted in a single extraction resulting in significant reduction in labor and assay time.

METHODS:

The 3.2 mm DBS were extracted by incubating at 45 °C for 45 min with 100 μl of acetonitrile (ACN)-water-formic acid mixture containing hydrazine and stable-isotope labeled internal standards of AA, AC and SUAC. The extract was derivatized with n-butanolic-HCl and analyzed by LC-MS/MS.

RESULTS:

The average inter-assay CVs for, AA, AC and SUAC were 10.1, 10.8 and 7.1% respectively. The extraction of analytes with ACN-water mixture showed no significant difference in their recovery compared to commonly used solvent MeOH. The concentration of hydrazine had considerable impact on SUAC extraction.

CONCLUSION:

We developed a new MS/MS derivatized method to detect AA/AC/SUAC in a single extraction process for screening Tyr I along with disorders of AA and AC.

• Authors: Kuldeep S Dhillon, Ajit S Bhandal, Constantino P Aznar, Fred W Lorey, Partha Neogi
• Journal: Clinica chimica acta; international journal of clinical chemistry (Clin Chim Acta) Vol. 412 Issue 11-12 Pg. 873-9 (May 12 2011) ISSN: 1873-3492 [Electronic] Netherlands
• PMID: 21216241 (Publication Type: Journal Article)
• Copyright: Published by Elsevier B.V.

Chemical References

• Amino Acids
• Heptanoates
• Hydrazones
• acylcarnitine
• succinylacetone
• Carnitine

Topics

• Amino Acids (analysis, chemistry, isolation & purification)
• Carnitine (analogs & derivatives, analysis, chemistry, isolation & purification)
• Chemical Fractionation (methods)
• Cost-Benefit Analysis
• Heptanoates (analysis, chemistry, isolation & purification)
• Humans
• Hydrazones (chemistry)
• Infant, Newborn
• Tandem Mass Spectrometry (methods)
• Time Factors
• Tyrosinemias (diagnosis)