ISO 15181-4:2008规定了根据ISO 15181-1中给出的程序测定从防污漆释放到人工海水中的吡啶三苯基硼烷（PTPB）含量的仪器和分析方法。它确定了人工海水提取物中的PTPB浓度，并给出了指定实验室条件下PTPB释放率的最终计算结果。 ISO 15181的本部分旨在通过分析单独的亚组分，同时测定给定防污漆（例如锌）可释放的PTPB和其他杀生物剂- 根据ISO 15181-1中给出的程序生成的人工海水提取物样品。 当与ISO 15181？1结合使用时，通过该方法定量测量释放率的实际限制为每天每平方厘米1.8微克到每天每平方厘米500微克。低于该范围的释放率的定量测量将需要文本中描述的额外浓缩步骤，或使用具有人工海水中PTPB定量下限的分析方法。

ISO 15181-4:2008 specifies the apparatus and analytical method for determining the amount of pyridine-triphenylborane (PTPB) that has been released from an antifouling paint into artificial seawater in accordance with the procedure given in ISO 15181？1. It determines the PTPB concentration in the artificial seawater extract and gives the final calculation for the release rate of PTPB under the specified laboratory conditions. This part of ISO 15181 is designed to allow the concurrent determination of PTPB and other biocides that can be released by a given antifouling paint (for example, zineb) through the analysis of separate sub-samples of an artificial seawater extract generated in accordance with the procedure given in ISO 15181？1. When used in conjunction with ISO 15181？1, the practical limits on the quantitative measurement of release rates by this method are from 1,8 micrograms per square centimetre per day to 500 micrograms per square centimetre per day. The quantitative measurement of release rates below this range will require an additional concentration step described in the text or the use of an analytical method with a lower limit of quantitation for PTPB in artificial seawater.