Using benzene as internal standard, the calibration factors of derivative of aldehydes 2,4 - dinitrophenylhydrazine ( DNPH ) were measured.将醛类物质与2, 4- 二硝基苯肼 ( DNPH ) 的衍生反应液直接进样,以苯为内标物,测定了甲醛 、 乙醛等醛类物质DNPH衍生物的校正因子....
a tablecloth edged with lace镶有花边的桌布He sat there ruminating and picking at the tablecloth.他坐在那儿沉思,轻轻地抚弄着桌布.Give the tablecloth a good shake before putting it away.桌布收起来之前要好好抖一抖....
He hied himself to the hospital.他赶紧去医院.He hied himself to the post office for his express mail.他赶紧去邮局取他的快件邮包.He hied himself to the post office.他赶紧去邮局....