Five different methods for the determination of 3-methoxy-4-hydroxymandelic acid (vanilmandelic acid, VMA) in urine were compared: a GLC-FID catecholamine metabolite profiling method, an HPLC method with electrochemical detection, the method of Pisano et al. ((1962) Clin. Chim. Acta 7, 285-291), a one dimensional paper Chromatographie method with diazotized p-nitroaniJine staining and the commercially available Bio-Rad VMA by Column Test. The comparison consisted of an imprecision study, a linearity check, a recovery study, a split sample comparison and an interference study. The best results of the imprecision study (n = 8) were found with the Bio-Rad and the HPLC method (within-run imprecision had a coefficient of Variation (CV) of 5.1% and 1.4%; between-days CV of 5.9% and 6.0% respectively for values of 32.4 μπιοΐ/ΐ and 24.5 μπιοΙ/1). The Pisano method had the poorest within-run CV (14.6%) and between-days CV (16.8%) for a value of 23.2 μΐηοΐ/ΐ. All methods showed good linearity. The mean recovery of the HPLC method was 101.3%; the mean recovery of the other four methods ranged from 93.9%-96.0%. The split sample comparison showed that the accuracy of the HPLC, the GLC and the Pisano method is comparable. The accuracy of the paper Chromatographie method and the Bio-Rad method had a positive bias compared with the HPLC method. Especially the positive bias of the Bio-Rad method can be very large. The HPLC method was not influenced by the compounds tested in the interference study, whereas the GLC method in some cases only suffered from overloading problems. The Pisano and the Bio-Rad method were most influenced by the interfering compounds tested. We conclude that the HPLC and the GLC methods are superior to the other three VMA methods. From an analytical point of view HPLC is the method of choice for determining 3-methoxy-4-hydroxymandelic acid in urine.
Vergleichende Untersuchung von f nf verschiedenen Methoden zur Bestimmung von 3-Methoxy-4-hydroxymandels ure im HarnZusammenfassung: F nf verschiedene Methoden zur Bestimmung von 3-Methoxy-4-hydroxymandels ure (Vanillinmandels ure, VMA) im Harn werden verglichen: 1. Gaschromatographische Methode mit Flammenionisations-Detektion zur Erstellung von Catecholaminmetabolit-Profiien. ! ) Present adress: Algerneen Ziekenhuis "de Tjongersscfaans", Thialfweg 44, NL-844I PW Heereiiveeru The Nctherlands. J. Clin. Chem. Clin. Biochem. / Vol. 21, 1983 / No. 7 Brought to you by | University of Glasgow Library Authenticated Download Date | 6/28/15 10:08 PM 418 Thomasson et al.: Determination of 3-methoxy-4-hydroxymandelic acid in urine 2. Hochleistungsfl ssigchromatographische (HPLC) Methode mit elektrochemischer Detektion. 3. Methode nach Pisano ((1962) Clin. Chim. Acta 7, 285-291). 4. Eindimensionale papierchromatographische Methode mit Detektion durch diaz tiertes p-Nitroanilin. 5. S ulen-Test Βίο-Rad VMA. . f Der Vergleich umfa te: a) Untersuchungen zur Pr zision (n = 8) Die besten Ergebnisse wurden mit der Bio-Rad und der HPLC-Methode erzielt: VK in der Serie 5-,l% und ...