哮喘儿童呼出气冷凝液 pH 测定影响因素的研究

Study on the influence factors of exhaled breath condensate pH detection of asthma children

目的探讨哮喘儿童呼出气冷凝液（EBC）pH测定的影响因素，建立规范、准确的哮喘儿童EBCpH测定方法。方法哮喘儿童EBC采用Rtube采集，pH测定采用微电极电位分析法。结果采样时冷凝管的温度（-18℃～4℃）、采样时间（10～30rain）对EBCpH测定结果无显著影响，高纯氩气吹扫4min后pH达到稳定；对不同pH的实际样品测定的日间精密度（以相对标准差RSD表示）范围为0．74％～1．01％：对pH分别为4．01、6．86、9．18的NISTpH标准缓冲液的测定值与理论值的相对偏差范围为0．11％-0．75％；用于pH测定的EBC样品可以保存6个月。结论通过规范EBCpH测定影响因素建立的测定方法，简单快捷，准确度高，重现性好，可以用于哮喘儿童EBCpH测定。

Objective To explore influence factors of exhaled breath condensate （EBC） pH detection and establish standard method for EBC pH detection of asthma children. Methods EBC samples were collected using Rtube EBC collection system, and pH values were detected by microelectrode method. Results The temperatures of sampling condenser tube （from - 18 to 4 ℃ ） and duration of collection （from 10 to 30 minutes） has no significant effect on EBC pH of asthma children. After degasification with argon for 4 minutes, the EBC pH became stable. The day to day precisions （relative standard deviation） were 0. 74% -1. 01% , and the relative deviations between theoretical values and detection values were 0. 11% -0.75% in determining different level of pH standard solutions. The EBC samples for pH detection could be store at -20℃ for 6 months. Conclusion＇ The established method by standardizing influence factors is accurate and convenient. It can be used in the detection of EBC pH of asthma children.