CN112394119B - 一种气相色谱-质谱法测定有机氯农药成分的检测方法 - Google Patents
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Abstract
本发明公开了一种气相色谱‑质谱法测定有机氯农药成分的检测方法,将待测有机氯农药的混合物用丙酮溶液作为溶剂溶解,形成待测样品溶液;利用特定波长和脉宽的超短脉冲激光对待测样品进行激发,将激发后的待测样品注入气相色谱‑质谱仪,全扫描记录定量离子对的峰面积,以浓度作为横坐标,峰面积作为纵坐标,绘制曲线;将绘制的曲线与有机氯农药成分A曲线进行比对,从而确定该待测样品中含有有机氯农药成分A。在原有的气象色谱‑质谱联用仪所具备的操作简单、效率高、可同时检测多种农药及大批量液体农药残留的基础上,以软电离的方式提高了系统分析物质的可靠性。
Description
技术领域
本发明涉及有农药的检测方法,特别是一种气相色谱-质谱法测定有机氯农药成分的检测方法。
背景技术
有机氯农药(OCPs)是用于防治植物病、虫害的组成成分中含有有机氯元素的有机化合物,作为杀虫剂被广泛用于防治疟疾、伤寒、霍乱等昆虫传染疾病,以提高农业中各种农作物的生产力。有机氯农药中的氯苯结构较稳定,生物体内酶难于降解,所以积存在动、植物体内的有机氯农药分子消失缓慢。目前人们已经认识到有机氯农药具有剧毒,对非靶向生物,如海洋哺乳动物、鸟类均有不良影响,并通过食物链进入人体的有机氯农药能在肝、肾、心脏等组织中蓄积,特别是由于这类农药脂溶性大,所以在体内脂肪中的积极因素贮更突出。蓄积的残留农药也能通过母乳排出,或转入卵蛋等组织,影响后代。这类农药会导致精神系统问题、超活跃障碍、II型糖尿病以及癌症等疾病。中国于六十年代已开始禁止将DDT、六六六用于疏菜、茶叶、烟草等作物上。但不乏一些发展中国家的某些地区由于立法不当,缺乏对其使用的监管,以及农民的无知继续使用此类农药。
传统的检测方法是利用气相色谱(GC)或液相色谱法分离有机氯农药[樊艳, 采用气相色谱(GC)法同时检测蜂蜜中的8种有机氯农药残留实验[J],粮食科技与经济,2019,44(11)],但这种方法可能产生假阳性误判,需要质谱的进一步确证。近年来,色谱-质谱联用技术在农药残留检测中的应用使得农药残留检测技术得以发展[王芳焕,QuEChERS-气相色谱-串联质谱法测定枸杞中农药残留[J],色谱, 2019,37(10)],其中电子电离(EI)源常用于非特异性硬电离,为使矩阵效益最小化,一般采用选择性离子监测模式。但矩阵的干扰提供了与被分析物类似的碎片模式,降低了分析结果的可靠性。
发明内容
本发明的目的在于解决以上现有技术的不足,提供一种气相色谱-质谱法测定有机氯农药成分的检测方法。
为实现以上方法,提供以下技术方案:
一种气相色谱-质谱法测定有机氯农药成分的检测方法,包括以下步骤:
S1:将待测有机氯农药的混合物用丙酮溶液作为溶剂溶解,形成待测样品溶液;
S2:利用特定波长和脉宽的超短脉冲激光对待测样品进行激发,所述波长和脉宽值通过一种有机氯农药成分A的吸收波长和跃迁能量确定;
S3:将激发后的待测样品注入气相色谱-质谱仪,采用全扫描的方式在 m/z40~400范围内分析待测样品,记录定量离子对的峰面积,以浓度作为横坐标,峰面积作为纵坐标,绘制曲线;
S4:将绘制的曲线与有机氯农药成分A曲线进行比对,从而确定该待测样品中含有有机氯农药成分A。
2、根据权利要求1所述的一种气相色谱-质谱法测定有机氯农药成分的检测方法,其特征在于,步骤S2的超短脉冲激光的波长和脉宽确定步骤:
S21:首先选取有机氯农药A,确认其的吸收带:利用高斯软件模拟A的最小分子结构,计算分子结构中电子从基态跃迁到中间态需要的能量e1以及从中间态跃迁到电离态所需的能量e2,
S22:由电子跃迁能量确定A的吸收波长为L1和L2;
S23:利用光学参量放大器调制超短脉冲激光设备的紫外光波波长L,使紫外光波波长L等于A的吸收波长L1;
S24:利用超短脉冲激光设备内的光栅进行色散调节,使得照射到样品处的激光脉宽Δt;计算方法如下:
电离态生成速率:
其中N0、N2分别为基态、电离态上粒子总密度;η12、η3、η4分别是双光子电离跃迁几率、分子离子的自解和光解速率,I(t)为激光光强,当激光发出的两个光子的能量与电子从基态跃迁到电离态所需的能量差小于3eV时,公式后两项可忽略不计,即
优选地,相色谱-质谱仪的气相条件:
色谱柱:DB-5石英毛细管柱,其中,柱长为30m,直径为0.25mm,膜厚为 0.25μm;
色谱柱温度:色谱柱初始温度50℃保持1min,然后以25℃/min程序升温至125℃,再以10℃/min升温至300℃,保持10min,;
进样口温度:250℃;
微通道信号采集器配有的数字转换器对获得的信号进行记录;
用飞行时间质谱法测定气相色谱柱中分析物,气相色谱与质谱仪之间的转移线温度维持在250℃。
有益效果:本发明综合超短脉冲离子激发技术和气相色谱-质谱检测技术,在原有的气象色谱-质谱联用仪所具备的操作简单、效率高、可同时检测多种农药及大批量液体农药残留的基础上,以软电离的方式提高了系统分析物质的可靠性。
具体实施方式
为使本发明实施例的目的、技术方案和优点更加清楚,下面将结合本发明实施例,对本发明实施例中的技术方案进行清楚、完整地描述,显然,所描述的实施例仅仅是本发明一部分实施例,而不是全部的实施例。因此,以下对提供的本发明的实施例的详细描述并非旨在限制要求保护的本发明的范围,而是仅仅表示本发明的选定实施例。基于本发明的实施例,本领域技术人员在没有做出创造性劳动的前提下所获得的所有其他实施例,都属于本发明保护的范围。
一种气相色谱-质谱法测定有机氯农药成分的检测方法,包括以下步骤:
S1:将待测有机氯农药的混合物用丙酮溶液作为溶剂溶解,形成待测样品溶液;
S2:利用特定波长和脉宽的超短脉冲激光对待测样品进行激发,所述波长和脉宽值通过一种有机氯农药成分A的吸收波长和跃迁能量确定;
S3:将激发后的待测样品注入气相色谱-质谱仪,采用全扫描的方式在 m/z40~400范围内分析待测样品,记录定量离子对的峰面积,以浓度作为横坐标,峰面积作为纵坐标,绘制曲线;
S4:将绘制的曲线与有机氯农药成分A曲线进行比对,从而确定该待测样品中含有有机氯农药成分A。
步骤S2的超短脉冲激光的波长和脉宽确定步骤:
S21:首先选取有机氯农药A,确认其的吸收带:利用高斯软件模拟A的最小分子结构,计算分子结构中电子从基态跃迁到中间态需要的能量e1以及从中间态跃迁到电离态所需的能量e2,
S22:由电子跃迁能量确定A的吸收波长为L1和L2;
S23:利用光学参量放大器调制超短脉冲激光设备的紫外光波波长L,使紫外光波波长L等于A的吸收波长L1;
S24:利用超短脉冲激光设备内的光栅进行色散调节,使得照射到样品处的激光脉宽Δt;计算方法如下:
电离态生成速率:
其中N0、N2分别为基态、电离态上粒子总密度;η12、η3、η4分别是双光子电离跃迁几率、分子离子的自解和光解速率,I(t)为激光光强,当激光发出的两个光子的能量与电子从基态跃迁到电离态所需的能量差小于3eV时,公式后两项可忽略不计,即
相色谱-质谱仪的气相条件:
色谱柱:DB-5石英毛细管柱,其中,柱长为30m,直径为0.25mm,膜厚为 0.25μm;
色谱柱温度:色谱柱初始温度50℃保持1min,然后以25℃/min程序升温至125℃,再以10℃/min升温至300℃,保持10min,;
进样口温度:250℃;
微通道信号采集器配有的数字转换器对获得的信号进行记录;
用飞行时间质谱法测定气相色谱柱中分析物,气相色谱与质谱仪之间的转移线温度维持在250℃。以上所述,仅为本发明的具体实施方式,但本发明的保护范围并不局限于此,任何熟悉本技术领域的技术人员在本发明揭露的技术范围内,可轻易想到变化或替换,都应涵盖在本发明的保护范围之内。因此,本发明的保护范围应所述以权利要求的保护范围为准。
Claims (2)
1.一种气相色谱-质谱法测定有机氯农药成分的检测方法,其特征在于,包括以下步骤:
S1:将待测有机氯农药的混合物用丙酮溶液作为溶剂溶解,形成待测样品溶液;
S2:利用特定波长和脉宽的超短脉冲激光对待测样品进行激发,所述波长和脉宽值通过一种有机氯农药成分A的吸收波长和跃迁能量确定;
其中,超短脉冲激光的波长和脉宽确定步骤包括:
S21:首先选取有机氯农药A,确认其的吸收带:利用高斯软件模拟A的最小分子结构,计算分子结构中电子从基态跃迁到中间态需要的能量e1以及从中间态跃迁到电离态所需的能量e2;
S22:由电子跃迁能量确定A的吸收波长为L1和L2;
S23:利用光学参量放大器调制超短脉冲激光设备的紫外光波波长L,使紫外光波波长L等于A的吸收波长L1;
S24:利用超短脉冲激光设备内的光栅进行色散调节,使得照射到样品处的激光脉宽Δt;计算方法如下:
电离态生成速率:
其中N0、N2分别为基态、电离态上粒子总密度;η12、η3、η4分别是双光子电离跃迁几率、分子离子的自解和光解速率,I(t)为激光光强,当激光发出的两个光子的能量与电子从基态跃迁到电离态所需的能量差小于3eV时,公式后两项可忽略不计,即
S3:将激发后的待测样品注入气相色谱-质谱仪,采用全扫描的方式在m/z40~400范围内分析待测样品,记录定量离子对的峰面积,以浓度作为横坐标,峰面积作为纵坐标,绘制曲线;
S4:将绘制的曲线与有机氯农药成分A曲线进行比对,从而确定该待测样品中含有有机氯农药成分A。
2.根据权利要求1所述的一种气相色谱-质谱法测定有机氯农药成分的检测方法,其特征在于,气相色谱-质谱仪的气相条件:
色谱柱:DB-5石英毛细管柱,其中,柱长为30m,直径为0.25mm,膜厚为0.25μm;
色谱柱温度:色谱柱初始温度50℃保持1min,然后以25℃/min程序升温至125℃,再以10℃/min升温至300℃,保持10min;
进样口温度:250℃;
微通道信号采集器配有的数字转换器对获得的信号进行记录;
用飞行时间质谱法测定气相色谱柱中分析物,气相色谱与质谱仪之间的转移线温度维持在250℃。
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