title: Problems and progress in analytical methods.
mesh_terms: D001151:Arsenic / Q000032:analysis; D002845:Chromatography; D003634:DDT / Q000032:analysis; D005504:Food Analysis; D005506:Food Contamination; D006846:Hydrocarbons, Halogenated / Q000032:analysis; D007854:Lead / Q000032:analysis; D007880:Legislation, Drug; D013058:Mass Spectrometry; D008628:Mercury / Q000032:analysis; D008722:Methods; D009566:Nitrates / Q000032:analysis; D009573:Nitrites / Q000032:analysis; D009584:Nitrogen / Q000032:analysis; D009602:Nitrosamines / Q000032:analysis; D009942:Organometallic Compounds / Q000032:analysis; D010575:Pesticides / Q000032:analysis; D011048:Polarography; D013053:Spectrophotometry; D013057:Spectrum Analysis; D014131:Trace Elements / Q000032:analysis
chemical_list: D006846:Hydrocarbons, Halogenated; D009566:Nitrates; D009573:Nitrites; D009602:Nitrosamines; D009942:Organometallic Compounds; D010575:Pesticides; D014131:Trace Elements; D007854:Lead; D003634:DDT; D008628:Mercury; D001151:Arsenic; D009584:Nitrogen