Associated Dataset for the Simultaneous Determination of Vanillylmandelic Acid and Homovanillic Acid in Urine of Children with Neuroblastoma by High Performance Liquid Chromatography-Fluorescence Detection

Data were generated as follows: 24‑h urine samples were collected and total urine volume was recorded; 0.5–1 mL of concentrated hydrochloric acid per 100 mL of urine was added as a preservative, and samples were stored at –20 °C. Sample pretreatment employed liquid‑liquid extraction: 200 μL of urine was mixed with 800 μL of ethyl acetate, shaken at 150 r/min for 10 min, centrifuged at 13,300 g for 15 min, and 600 μL of the supernatant was taken and dried under vacuum centrifugal concentration.

The residue was reconstituted in 200 μL of phosphate‑buffered saline (70 mmol/L, pH 5.54)–methanol (97:3, v/v), centrifuged again at 13,300 g for 10 min, and 20 μL of the supernatant was injected for analysis. Chromatographic separation was performed on a Shim‑Pack VP‑ODS column (150 mm × 4.6 mm, 5 μm) with gradient elution using 70 mmol/L phosphate buffer (pH 5.54) and methanol as the mobile phase.

The column temperature was 30 °C, the flow rate was 0.8 mL/min, and fluorescence detection was carried out at excitation and emission wavelengths of 278 nm and 320 nm, respectively. Major instruments used included an Agilent 1100 high‑performance liquid chromatography system with G1321A fluorescence detector, a Thermo Fisher Scientific U3000 HPLC system with FLD‑3100 Dual‑PMT fluorescence detector, a Fresco 17 refrigerated benchtop centrifuge, and a Savant DNA120 vacuum centrifugal concentrator.The dataset comprises two major parts: method validation data and clinical application data.

Method validation data include: calibration curves and correlation coefficients (R² > 0.997 for both analytes) over the linear ranges of 1.50–300.0 mg/L for VMA and 3.00–600.0 mg/L for HVA; limits of detection (LOD, 0.08 mg/L for VMA and 0.13 mg/L for HVA) and limits of quantification (LOQ, 0.31 mg/L for VMA and 0.53 mg/L for HVA); recoveries at three spiked levels (96.60%–106.78% for VMA and 99.32%–108.98% for HVA) with relative standard deviations (RSD) all below 5%; intra‑day precision (1.51%–3.18%) and inter‑day precision (3.29%–4.49%); interference test results for ascorbic acid (no significant interference in the range of 0–2.0 mg/L); and stability data for samples stored at –20 °C for up to 24 days and for reconstituted samples stored at 4 °C for up to 7 days.

Clinical application data include: the distribution of 24‑h urinary VMA and HVA levels in each disease group and the control group; correlation analysis between the HPLC method and the clinical microcolumn colorimetric (MC) method for VMA determination (Spearman correlation R = 0.85, P < 0.001); receiver operating characteristic (ROC) curve analysis results including area under the curve (AUC), sensitivity, specificity, cut‑off values, and likelihood ratios (the combined HPLC assay for VMA and HVA achieved an AUC of 0.98); and paired pre‑ and post‑operative VMA and HVA monitoring data for NB patients.All figures (nine charts, including method optimization plots, chromatograms, distribution plots, correlation scatter plots, and ROC curves) and three data tables (recovery table, interference test table, and diagnostic performance table) from the paper are provided in the dataset.

Each table is clearly labeled with row and column headers and complete units of measurement (concentration in mg/L, volume in mL or L, temperature in °C, time in min, centrifugal force in g, etc.). All data in the dataset are actual experimental measurements, and no missing data are present. For validation parameters such as recovery, precision, and stability, results are expressed as mean values with relative standard deviations (RSD); all reported errors are within acceptable ranges for bioanalytical quantification (RSD < 5%).

Potential sources of error include instrumental injection variation, losses during liquid‑liquid extraction, and matrix effects, but these have been controlled within reasonable limits by using matrix‑matched calibration curves and strict quality control procedures. Data files are provided in common formats (e.g., .tif for images and .xlsx for tables), which can be opened and viewed with standard image viewers and Microsoft Excel; no special software is required.