Table olives, a widely consumed delicacy, are often selected by consumers based on the shade of their green color. The appealing coloration of fresh olives fades to brown or pale yellow during the industrial processing necessary for commercialization and storage, as a result of the degradation of chlorophyll a and b to their corresponding pheophytins and other chlorophyll degradation products (CDP). The re-greening of table olives may be achieved by complexation of CDP with Cu2+, to form stable bright green copper CDP (Cu-CDP) complexes. To study this phenomenon, we developed a novel method to separately extract lipophilic and hydrophilic Cu-CDP and quantify Cu-CDP by UHPLC combined with inductively coupled plasma isotope dilution mass spectrometry (UHPLC-ICP-ID-MS) using post-column isotopic dilution with 65Cu. This technique does not require species-specific calibration standards and was applied to survey the Cu-CDP composition of the various types of table olives sold in the US market. The CDP and Cu-CDP extracted from table olives were identified by high resolution full-scan mass spectrometry. Total elemental Cu in table olives was measured by microwave digestion followed by ICP-MS detection and correlated with the content of Cu-CDP. Pale yellow olives contained <1 mg/kg lipophilic Cu-CDP and <3.5 mg/kg total elemental Cu. Bright green table olives contained 4-22 mg/kg lipophilic Cu-CDP and 14.4-161 mg/kg total elemental Cu in contrast to <6 mg/kg reported for natural abundance, indicating the formation of Cu-CDP was achieved by addition of copper salts. A dark green sample with 2.5 mg/kg of total copper and 0.267 mg/kg lipophilic Cu-CDP may have been processed by addition of sodium copper chlorophyllin (SCC); the higher content of Cu isochlorin e4 compared to Cu 152-Me-chlorin e6 supports this conclusion.

中文翻译：

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超高效液相色谱-电感耦合等离子体同位素稀释质谱法定量测定绿橄榄中的叶绿素铜。

食用橄榄是一种被广泛使用的美味佳肴，通常由消费者根据其绿色的阴影来选择。由于叶绿素a和b降解为相应的脱镁叶绿素和其他叶绿素降解产物（CDP），在工业化和储存所需的工业加工过程中，新鲜橄榄的诱人色泽逐渐淡化为棕色或淡黄色。食用橄榄的重新绿化可以通过CDP与Cu2 +络合形成稳定的亮绿色铜CDP（Cu-CDP）复合物来实现。为了研究这种现象，我们开发了一种新方法，可通过柱后同位素稀释，通过UHPLC和电感耦合等离子体同位素稀释质谱法（UHPLC-ICP-ID-MS）分别提取亲脂性和亲水性Cu-CDP并定量Cu-CDP。 65Cu 该技术不需要特定于物种的校准标准，并且被用于调查在美国市场上出售的各种食用橄榄的Cu-CDP组成。通过高分辨率全扫描质谱法鉴定了从食用橄榄中提取的CDP和Cu-CDP。食用橄榄中的总元素铜通过微波消解，然后通过ICP-MS检测来测量，并与Cu-CDP的含量相关。淡黄色橄榄的脂溶性Cu-CDP含量<1 mg / kg，总Cu含量<3.5 mg / kg。鲜绿色的食用橄榄中含有4-22 mg / kg的亲脂性Cu-CDP和14.4-161 mg / kg的元素铜总量，而自然丰度<6 mg / kg，这表明通过添加以下物质可以形成Cu-CDP。铜盐。暗绿色样品，铜总含量为2.5 mg / kg，0。267 mg / kg的亲脂性Cu-CDP可通过添加叶绿素铜钠（SCC）来处理；与Cu 152-Me-​​chlorin e6相比，Cu isochlorin e4的含量更高支持了这一结论。