Titre du document / Document title

Quantitative determination of heme for forensic characterization of Bacillus spores using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Auteur(s) / Author(s)

WHITEAKER Jeffrey R. ⁽¹⁾ ; FENSELAU Catherine C. ⁽¹⁾ ; FETTEROLF Dean ⁽²⁾ ; STEELE Darin ⁽²⁾ ; WILSON David ⁽²⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, ETATS-UNIS
⁽²⁾ Federal Bureau of Investigation, Quantico, Virginia 22134, ETATS-UNIS

Résumé / Abstract

A quantitative method was developed for the determination of heme (ferriprotoporphyrin IX) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). The method was designed for forensic characterization of the use of blood agar in preparation of Bacillus spores. An alkali wash of 0.3 M ammonium hydroxide was used to solubilize heme from spore samples. The wash was concentrated and analyzed by MALDI-TOFMS. Experimental parameters were optimized to obtain the best signal intensity, maximize signal reproducibility, and improve day-to-day repeatability of the measurement. Sinapinic acid was found to be the best matrix. A sandwich sample preparation protocol was determined to increase the shot-to-shot and point-to-point reproducibility of the measurement. Cobalt(III) protoporphyrin was used as an internal standard and the analyte/ internal standard ratio responses from solutions of known concentrations were used to construct a calibration curve (R² = 0.993). Limits of detection and quantitation for heme were calculated to be ∼0.4 (200 fmol) and 0.8 pM (400 finol), respectively. Spore samples prepared on blood agar and nonblood agar were analyzed using the method. Heme was detected at a concentration of ∼0.3 ng/mg of spore on samples prepared on blood agar and purified by extensive washing. Heme was not detected on spore samples prepared without blood.

Revue / Journal Title

Analytical chemistry   ISSN 0003-2700   CODEN ANCHAM 

Source / Source

2004, vol. 76, n^o10, pp. 2836-2841 [6 page(s) (article)] (26 ref.)

Langue / Language

Anglais

Editeur / Publisher

American Chemical Society, Washington, DC, ETATS-UNIS  (1947) (Revue)

Mots-clés anglais / English Keywords

Bacteria ; Bacillales ; Bacillaceae ; Spores ; Bacillus ; Heme ; Agar ; Cobalt compound ; Ammonium hydroxide ; Blood ; Optimization ; Detection limit ; Standard curve ; Internal standard ; Protoporphyrin ; Sample preparation ; Repeatability ; Reproducibility ; Mass spectrometry ; Time of flight method ; Matrix assisted laser desorption ionization ; Forensic science ; Quantitative analysis ;

Mots-clés français / French Keywords

Bactérie ; Bacillales ; Bacillaceae ; Spore ; Bacillus ; Hème ; Gélose ; Cobalt composé ; Ammonium hydroxyde ; Sang ; Optimisation ; Limite détection ; Courbe étalonnage ; Etalon interne ; Protoporphyrine ; Préparation échantillon ; Répétabilité ; Reproductibilité ; Spectrométrie masse ; Méthode temps vol ; MALDI ; Police scientifique ; Analyse quantitative ;

Mots-clés espagnols / Spanish Keywords

Bacteria ; Bacillales ; Bacillaceae ; Espora ; Bacillus ; Heme ; Agar ; Cobalto compuesto ; Amonio hidróxido ; Sangre ; Optimización ; Límite detección ; Curva contraste ; Patrón interno ; Protoporfirina ; Preparación muestreo ; Repetibilidad ; Reproductividad ; Espectrometría masa ; Método tiempo vuelo ; MALDI ; Ciencia forense ; Análisis cuantitativo ;

Localisation / Location

INIST-CNRS, Cote INIST : 120 B, 35400011191286.0220