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Water is one of the most important compounds and plays an important role in biological process, chemical synthesis and material science. Thus, studies about water and related particles water radical cations are always the top research fields. In this work, water dimer radical cation (H2O)2+• was prepared using home made low energy corona discharge device at ambient condition, and its structure was further studied using collision induced dissociation (CID) experiment and isotope labelling method. The dissociation results showed that (H2O)2+• (m/z 36) will lose OH• and H2O to give ions of m/z 19 (H2OH+) and m/z 18 (H2O+•), competitively, revealing that (H2O)2+•can exist in two different structures, including ［H2OH+—•OH］ (hydrogen atom bound structure (A)) and ［H2O∴OH2］+ (oxygen oxygen atom bound structure (B)). Structure A is asymmetry and structure B is symmetry. Furthermore, isotopic labeled experiments were conducted using deuterated water (D2O) and 18O-enriched water (H218O). The dissociation of (D2O)2+•(m/z 40) gave the corresponding protonated water D2OD+ (m/z 22) and water radical cation (D2O)+• (m/z 20). Dissociation of (H2O•D2O)+•(m/z 38) produced the protonated water H2OD+ (m/z 20)/D2OH+ (m/z 21), and water radical cation H2O+• (m/z 18), HOD+• (m/z 19), D2O (m/z 20)+•. In 18O-enriched water (H218O) labelled isotopic experiments, (H2O•H218O)+•(m/z 38) also was dissociated into its corresponding protonated water H2OH+(m/z 19)/H218OH+(m/z 21) and water radical cation H2O+• (m/z 18) and H218O+•(m/z18). The CID and the isotope labelling results indicated that water dimer radical cation (D2O)2+•, (H2O•D2O)+• and (H2O•H218O)+•also exist A and B two structured forms. In conclusion, two structures of water dimer radical cation (H2O)2+•will further reveal that mass spectrometry may help to elucidate chemical mechanism related with (H2O)2+•in the biological processes and chemical reactions.

Metal element contents in water samples are commonly determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). ICP-MS has a low detection limit and wide linear range, but has a high power, large gas consumption, and high cost. A rapid method for the determination of calcium ions in water samples was developed by using Microwave Plasma Torch (MPT)-Mass Spectrometry coupled with pneumatic nebulization. The effects of carrier gas flow rate and the support gas flow rate on calcium response signal were investigated. The detection limit of this method is 224.56 ng/L, relative standard deviations (RSDs) are 1.2%-9.8%, and recoveries range from 86.3% to 110.4%. This method avoids sample pretreatment, and has a short analysis time, good sensitivity and precision. This method provides a new approach for the determination of metal ions in environmental water and may be used for in situ analysis in the future.

The distinction between natural stones such as marble and granite, and artificial stones formed mostly by unsaturated polyester resin with the addition of disintegrating slag of natural stone and some additives is difficult to determine accurately and quickly by chemical composition. Consequently, the development of Infrared Reflection Spectroscopy (IRS) has been established for for this purpose, but has limitations due to the high purity requirement of samples. Based on the high ability of thermal desorption and ionization of Microwave Plasma Torch (MPT), analyte could be ionized in a short time. In this study, Microwave Plasma Torch Mass Spectrometry (MPT-MS) was used to directly analyze natural and artificial stone without sample pretreatment. The fingerprint mass spectra of these stones were obtained in the mass range of m/z 50-1000. All data from artificial stones and natural stones were analyzed by principal component analysis (PCA) for differentiation of artificial and natural stones. The results show that abundant fingerprints of stones were acquired by MPT-MS. With the application of PCA, natural stones were successfully and rapidly differentiated from artificial stones. CO2 and H2O molecular clusters were desorbed from natural stones, however, organics (i.e. adhesives) were desorbed from artificial stone. Herein, MPT-MS is a new mass spectrometry technology under atmospheric pressure. Without the assistance of spray, laser, matrix and heat, the stones can be analyzed by MPT-MS directly. The method has high analytical speed (1 min per sample), high sensitivity, and does not require sample pretreatment. The results indicate that direct MPT-MS analysis allows rapid differentiation of untreated solid materials, such as construction stones, at the molecular level.

Graphite and clay mixed in pencil lead, with non-standard proportions will be read correctly by computer card reading equipment and identified by non-specialists. In this paper, a rapid and effective method based on atmospheric mass spectrometry utilizes quality evaluation for the pencil lead by the analysis of different degrees of blackness (graphite content) and hardness. At ambient pressure, with about 40% relative humidity, pencil lead was directly used as an ionization device to produce coronal discharge and impact the mass spectrum signals in air at high voltage. Here, experimental conditions were optimized, the relationship between the graphite content in pencil leads (e.g. 4B, 3B, 2B, HB, H and 2H) and their mass spectrum signals were analyzed, and six kinds of pencil leads were discriminated by principal component analysis (PCA). The results showed that the discharge behaviors of the different types of pencil lead have an influence on the signal intensity, which increases with the increasing graphite content in pencil lead. On the basis of the mass spectra raw data, six kinds of pencil lead were correctly identified to more than 99%. The method is available with a good reproducibility and straightforward operation, providing a rapid tool for the quality evaluation for commercially available pencil lead.