[Determination of Haloacetic Acids, Disinfection Byproducts, in Tap Water with Reversed-Phase Ultra-Performance Liquid Chromatography-High Resolution Mass Spectrometry].

Objective: To establish a method for quantitative analysis of haloacetic acids (HAAs), disinfection byproducts, in tap water with reversed-phase ultra-performance liquid chromatography-quadrupole-orbitrap high resolution mass spectrometry. Methods: Tap water samples were collected and 0.70 g/L ascorbic acid was added to eliminate residual chlorine. Then, the water samples were directly injected into the instrument for analysis after filtration. After separation on a pentafluorobenzene (PFP) column with an inner diameter of 1.0 mm at a higher linear velocity and a lower volume flow rate compared with those of a narrow-bore column, nine HAAs, namely, monochloroacetic acid (MCAA), monobromoacetic acid (MBAA), dichloroacetic acid (DCAA), bromochloroacetic acid (BCAA), dibromoacetic acid (DBAA), trichloroacetic acid (TCAA), bromodichloroacetic acid（BDCAA), chlorodibromoacetic acid (CDBAA) and tribromoacetic acid (TBAA), were examined by negative electrospray ionization and full MS/dd-MS 2 acquisition mode. In order to adjust for the matrix effect, matrix matching calibration curves were used to quantitate the nine HAAs. Results: Good linearity was obtained for each of the nine HAAs within their respective linear ranges. The detection limits and quantification limits of the method were 0.020-1.0 µg/L and 0.060-3.0 µg/L. The recoveries were 69.8%-119%. Conclusion: The proposed method showed strengths in separation speed and qualitative accuracy. It did not require for complicated pretreatment procedures and can meet the need of tap water sample analysis.

[The Screening Approaches for 34 Common Drugs and Metabolites in Biological Samples by Liquid Chromatography Orbital Trap Mass Spectrometry].

Objective: To establish a high-performance liquid chromatography orbital trap mass spectrometry (HPLC-Obitrap MS) method for screening 34 common drugs and metabolites in biological samples. Methods: The target analytes in urine and blood samples were extracted with ethyl acetate, concentrated by nitrogen blowing and redissolved. The hair samples were washed with water and acetone, dried and cut into bits of about 1 mm, and then crushed in a freezing grinder. The analytes were extracted with methanol, and after filtration, the filtrate was used for instrumental analysis. Hypersil Gold PFP (2.1 mm×100 mm, 3 µm) column was used for chromatographic separation. Methanol and 5 mmol/L ammonium acetate solution were used as mobile phase with gradient elution at a flow rate of 400 µL/min. Mass spectrometry was done by electrospray positive and negative ion alternation mode. The data were collected using Full MS and Full MS/dd-MS2 mode. Xcalibur 4.0 software was used to control instruments and to collect data, and TraceFinder 3.3 was used for screening and identification. Results: The method's detection limits for 34 drugs and their metabolites in blood, urine and hair samples were 3.30-10700 ng/L, 4.43-5440 ng/L, 0.0350-4.21 µg/kg, respectively. The intra-day and inter-day precisions of the spiked samples at the levels of 5.0, 10, and 20 µg/L were 3.50%-6.00% and 4.18%-9.90%, respectively. A total of 1125 biological samples of urine, blood and hair were collected and screened. The results showed that 96.7% of the drug users were taking a single drug, while 3.3% were mixed drug users. The main types of drug of abuse were methamphetamine (75.8%), heroin (18.5%), ketamine (2.4%) and other drugs (3.3%), and 87.9% of the positive samples were from male users. Compared with the results of high-performance liquid chromatography triple quadrupole mass spectrometry, this method can be used to identify more types of drugs in one run and to conduct retrospective analysis. Conclusion: The method established in the study is simple and sensitive and is well suited for the screening of common drugs and metabolites in biological samples.

[Study on the Analytical Method of Solid Phase Extraction-Ultra Performance Liquid Chromatography Tandem Quadrupole Linear Ion Trap Mass Spectrometry for 12 Perfluorinated Compounds in Human Urine].

OBJECTIVE: To establish a method for simultaneous determination of 12 kinds of perfluorinated compounds (PFCs) in human urine based on ultra performance liquid chromatography tandem quadrupole linear ion trap mass spectrometry (UPLC-QTtrap-MS). METHODS: After pH adjustment with 2% formic acid, the urine samples were loaded on a WAX solid phase extraction (SPE) cartridge for extraction, purification and concentration. The eluates were collected, concentrated to dryness under nitrogen, and reconstituted with 10 mmol/L ammonium acetate aqueous solution-methanol ( V water∶ V methanol = 70∶30) before injection. UPLC was performed on a C 18 cartridge, and methanol and 10 mmol/L ammonium acetate aqueous solution was used as mobile phases with gradient elution. QTtrap-MS was operated in multiple reaction monitoring (MRM) mode, and the internal standard calibration curves were applied for quantitative analysis. RESULTS: Good linearity was obtained in the linear range, with the method detection limits and method quantification limits being 0.032 ng/L-6.5 ng/L and 0.10 ng/L-21 ng/L, respectively, for the 12 kinds of PFCs. The spiked recoveries of the 12 kinds of PFCs were 91.5%-114%, with the intra-day precision and the inter-day precision being 0.57%-16.0% and 1.88%-20.1%, respectively. The established method was applied to the determination of 12 kinds of PFCs in the urine samples of primary school students collected in one area. Nine kinds of PFCs were detected in the urine samples in this area. Among the PFCs detected, perfluorobutanesulfonic acid (PFBS) and perfluorooctanoic acid (PFOA) were the main PFCs found in the student urine samples. CONCLUSION: The method established in this study could be used to simultaneously examine 12 kinds of PFCs in urine. The method combined SPE with isotope internal standard correction and achieved good sensitivity and accuracy.

[Determination of Aromatic Compounds Metabolites in Human Urine by Solid Phase Extraction-liquid Chromatography-Tandem Mass Spectrometry].

OBJECTIVE: To establish the method based on high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) with solid phase extraction (SPE) for simultaneous determination of the biological metabolites of aromatic compounds, including N-acetyl-S-phenyl-L-cysteine (SPMA), N-acetyl-S-benzyl-cysteine (SBMA), p-nitrophenol (PNP), methylhippuric acids (MHA), p-Aminophenol (PAP), mandelic acid (MA), phenylglyoxylic acid (PGA) and 1-hydroxypyrene (1-OHP) in urine. METHODS: After adding 20 µL of ß-glucuronidase and 1 mL ammonium acetate buffer solution in 1 mL of urine, the sample was digested in a 37 ℃ incubator for 20 h. After digestion, the enzymatic hydrolysate was purified by PRIME HLB solid phase extraction column. The target compounds were eluted with 4 mL of acetonitrile and blown to dryness with nitrogen, reconstituted with 0.20 mL of methanol. Injected the sample solution into LC-MS/MS system for analysis after filtering with 0.22 µm filter membrane. LC separation was carried out on a reversed-phase C18 column (2.1 mm×150 mm, 3.5 µm); gradient eluting was performed at a flow rate of 0.2 mL/min. The water containing 0.1% formic acid was used as mobile phase A and methanol was used as mobile phase B. The mass spectrometry was performed with multiple reaction monitoring (MRM) mode, using alternating positive and negative ions, and internal standard curves were used for quantification. RESULTS: The eight metabolites showed good linearity within the range of 1-100 ng/mL, with a correlation coefficients greater than 0.995, and the relative precision deviation (RSDs) was 0.050%-9.95%. The method detection limits (MDLs) of the eight target metabolites were 0.041-0.12 ng/mL. The proposed method was used for urine sample analysis and the spiked recoveries were 80.1%-114.0%. CONCLUSION: The established method is quick, sensitive and accurate; it meets the requirementof the biological monitoring of aromatic compounds for the general population and occupational population.