Determination of urinary 5-S-cysteinyldopa by high-performance liquid chromatography

Serum concentration of 5‐S‐cysteinyldopa in patients with melanoma

“…Early detection of distant metastasis with tumour markers would improve the prognosis of the disease. 5-S-cysteinyldopa is formed during the biosynthesis of melanins by a tyrosinase dependent mechanism [1,6] (Fig. 6.).…”

“…5-S-CD was determined by a Merck-Hitachi HPLC (Merck KGaA, Darmstadt, Germany) consisting of an L-6200 A Intelligent Pump, D-2500 Chromato Integrator, AS 2000 A Autosampler and equipped with a LaChrom L-3500 A amperometric detector (settings: 0´75 V, ®lter: 2 s) [6]. Chromatography was performed on a Supelco RP-C18 Column (Sigma-Aldrich Co., Bellefonte, PA, USA) using isocratic elution with a mobile phase contain-ing 10 g L À1 phosphoric acid, 0.1 mmol L À1 Na 2 EDTA and 7 g L À1 methanesulfonic acid.…”

“…Elevated S 100 protein levels were seen in patients with metastasised disease [17]. In addition, the assay was found suitable for the screening of high-risk patients and for the monitoring of therapy [6]. On the basis of our previous results the S 100 values, like 5-S-CD levels, correlate with the Stage and progression of melanoma, but S 100 seems to be more sensitive [1,14].…”

Development of a mass spectrometry method for the determination of a melanoma biomarker, 5-S-cysteinyldopa, in human plasma using solid phase extraction for sample clean-up

“…It is thus possible to estimate the progression of melanoma by measuring the concentration of 5-SCD in blood or urine [1,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”

“…Concerning the extraction of 5-SCD from biological matrix, alumina extraction [9][10][11][12][13] was very often applied prior to HPLC analysis, sometimes coupled with an additional liquid-liquid extraction step. Enrichment methods with phenylboronate affinity gel have also been described [14,15].…”