Hutta Milan, Chalányová Mária, Halko Radoslav, Góra Róbert, Rybár Ivan, Pajchl Marek, Dokupilová Svetlana
Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia.
J Sep Sci. 2006 Aug;29(13):1977-87. doi: 10.1002/jssc.200600049.
A well established method of direct injection of larger than conventional sample volumes ranging from 0.1 mL to 10 mL in HPLC is the injection valve method in which a loop of tubing is totally or partially filled with sample. Recent HPLC pumps have a flow-rate setting accuracy of +/- 1-2% over a flow-rate range from 0.1 mL/min to 10 mL/min and the flow stability is 0.2% or less. Quarternary low pressure gradient pumps are widely available and used, but all their hydraulic lines are seldom utilised. The idea of using one line of a common commercial HPLC quaternary low-pressure pump for direct on-column injection (pumping) of large sample volumes ranging from 1 mL to 100 mL was tested. This approach was evaluated during practical work on the development of an RP-HPLC method of determination of residual atrazine and hydroxyatrazine. In lysimetric environmental experiments hydroxyatrazine was formed in situ in a soil column by hydrolysis of atrazine. The results proved the applicability of this approach not only in experiments with model mixtures of analytes at microg/L levels in solutions. Analysis of 20 mL of soil leachates and extracts of soil samples containing atrazine and hydroxyatrazine at the 10 microg/kg level (in dry soil) revealed that good figures-of-merit were preserved, even in the presence of a large excess of humic substances.
在高效液相色谱法（HPLC）中，一种成熟的直接进样方法是进样阀法，该方法可进样大于传统进样体积（范围为0.1 mL至10 mL）的样品，即通过将一段管路完全或部分充满样品来实现。最近的高效液相色谱泵在0.1 mL/min至10 mL/min的流速范围内，流速设定精度为±1 - 2%，流速稳定性为0.2%或更低。四元低压梯度泵广泛可得且被使用，但其所有液压管路很少被充分利用。本研究测试了使用普通商用HPLC四元低压泵的一条管路直接对1 mL至100 mL的大体积样品进行柱上进样（泵送）的想法。该方法在开发测定残留莠去津和羟基莠去津的反相高效液相色谱法的实际工作中进行了评估。在渗漏环境实验中，莠去津在土壤柱中通过水解原位生成羟基莠去津。结果证明该方法不仅适用于分析物浓度为微克/升水平的模型混合溶液实验。对20 mL含有10微克/千克水平（干土中）莠去津和羟基莠去津的土壤渗滤液和土壤样品提取物的分析表明，即使存在大量腐殖质，该方法仍能保持良好的品质因数。
