Due to international regulations, commonly used phthalates such as di(2-ethylhexyl) phthalate (DEHP) are being replaced by other phthalates, such as di-isononyl phthalate (DINP), and di-isodecyl phthalate (DIDP) and by alternative plasticizers (APs) with similar chemical characteristics, like di(isononyl)cyclohexane-1,2-dicarboxylate (DINCH), di(2-ethylhexyl) terephthalate (DEHTP), or di-(2-ethylhexyl) adipate (DEHA). Urinary concentrations of metabolites are frequently used in the exposure assessment of non-persistent chemicals and for biomonitoring purposes, the intra- and inter-day variability of the metabolites should be known. However, the short-term variability of AP and several phthalate biomarkers has not been investigated yet. In this study, we collected all spot samples from 10 healthy adults for 5 consecutive days and 24h pooled urine on one additional day to investigate the short-term variability of 22 biomarkers of phthalates and APs. Metabolites of DEP, DEHP, DiBP, DnBP, DBzP, DINP and DIDP were found in high detection frequencies, while metabolites of most APs were found in approximately 50% of the samples. The short-term reproducibility of metabolites with diet as primary source (DEHP, DINP, DIDP) was poor (intraclass correlation coefficient – ICC < 0.4), whereas biomarkers of DEP, DnBP, DiBP and BBzP showed good consistency, most likely due to more continuous sources resulting in less between-day variance. ICC values of AP metabolites were similar to those of DEHP, but more studies are required to confirm these findings. Overall, reproducibility improved considerably when values were corrected for urinary dilution and when only morning voids samples were considered. Levels in morning voids samples were consistent for 5 days and comparable to 24-h pooled urine for all metabolites except for OH-MEHTP, sum DINP and sum DIDP, which supports the use of morning voids in human biomonitoring studies.

根据国际法规，常用的邻苯二甲酸酯（例如邻苯二甲酸二（2-乙基己基）酯（DEHP））将被其他邻苯二甲酸酯（例如邻苯二甲酸二异壬酯（DINP）和邻苯二甲酸二异癸酯（DIDP））以及其他增塑剂替代（具有相似化学特性的APs，例如二（异壬基）环己烷-1,2-二羧酸酯（DINCH），对苯二甲酸二（2-乙基己基）酯（DEHTP）或己二酸二（2-乙基己基）酯（DEHA）。尿液中代谢物的浓度经常用于非持久性化学品的暴露评估中，并且出于生物监测的目的，应了解代谢物的日内和日间变化。但是，尚未研究AP和几种邻苯二甲酸酯生物标志物的短期变异性。在这个研究中，我们连续5天收集了来自10名健康成年人的所有现场样本，并在另一天收集了24小时的尿液，以调查22种邻苯二甲酸盐和AP的生物标记物的短期变异性。在高检测频率下发现DEP，DEHP，DiBP，DnBP，DBzP，DINP和DIDP的代谢物，而大多数AP的代谢物在大约50％的样品中被发现。以饮食为主要来源（DEHP，DINP，DIDP）的代谢物的短期再现性较差（类内相关系数– ICC <0.4），而DEP，DnBP，DiBP和BBzP的生物标志物显示出良好的一致性，这很可能是由于更多连续来源，导致日间差异较小。AP代谢物的ICC值与DEHP相似，但需要更多的研究来证实这些发现。总体，当校正尿液稀释值并且仅考虑早晨排尿样品时，可重复性得到了显着改善。早晨空洞样品的水平连续5天保持一致，并且与所有代谢物的24小时合并尿液相当，但OH-MEHTP，总DINP和总DIDP除外，这支持在人类生物监测研究中使用早晨空洞。