NOVELTY - The chemical sensor array has vibration detection units (110,115) that are fixed to a substrate (105) and provided with a piezoelectric element (138,148) with bottom and top sides. The first and second electrodes (130,135) are formed on the bottom side of the piezoelectric element. The second electrode is spaced apart from the first electrode. A conductive layer (170,175) is formed on the piezoelectric element. The conductive layer is spaced apart from the first and second electrodes. The conductive layer in the vibration detection unit is provided with different thickness.    USE - Chemical sensor array used in system for sensing analyte in analyte such as ammonia, acetone, hydrogen, methane, methyl mercaptan, ethane, isoprene, carbon monoxide, acetaldehyde and toluene in sample e.g. breath gas sample (all claimed) and liquid sample from mammal such as human for indicating health disorder in mammal e.g. diabetes.    ADVANTAGE - Since the conductive layer is formed on the piezoelectric element, the sample is contacted with the chemical sensor array for sensing an analyte. Since the piezoelectric material is provided with sufficient piezoelectric properties, the oscillatory electrical signals from the piezoelectric element are used to detect a change in the vibrational resonance frequency of the piezoelectric element. Since the chemical sensor array is provided with the small dimensions, the chemical sensor array is incorporated in mobile devices such as a cell phone or other hand-held electronics.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a method for sensing analytes in a sample;    (2) a method for making a chemical sensor array; and    (3) a system for sensing an analyte in sample.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of the chemical sensor array.    Substrate (105)    Vibration detection units (110,115)    Electrodes (130,135,140,145)    Piezoelectric elements (138,148)    Conductive layers (170,175)