Research progress on detection methods for nitrobenzene compounds in air / 中国职业医学

@#Abstract: Nitrobenzene compounds (NBCs) are widely used in the world. It has 40 isomers such as nitrobenzene, dinitrobenzene and nitrotoluene, that are highly toxic and difficult to degrade and can cause harm to human health in different degrees. At pres⁃ ent, there is no unified standard method and occupational exposure limit for the detection of NBCs in the air. In terms of sampling medium, solid adsorption tube is mostly used for trapping vapor state NBCs, and filter membrane and solid adsorption tube are mostly used in series for sampling coexist NBCs in vapor state and aerosol state. In the detection methods, gas chromatography and liquid chromatography are common, and ultraviolet spectrophotometry, Raman spectroscopy, ion migration spectrometry and some other rapid response methods and technologies are also used in the detection of NBCs. In the detection of NBCs by gas chro⁃ matography, capillary column separation is commonly used, and the main detectors are flame ionization detector, electron capture detector and mass spectrometry detector. It is of practical significance to establish a method with high sensitivity, strong practica⁃ bility, convenient operation, and can simultaneously collect and detect a variety of NBCs in different states.

Determination of dimethyl sulfate in workplace air by pre-column derivatization-high performance liquid chromatography / 中国职业医学

@#Abstract: Objective - - To establish a pre column derivatization high performance liquid chromatography method for detecting Methods dimethyl sulfate (DMS) in workplace air. DMS in workplace air was collected with mercaptopyridine impregnated （ silicone tube. The derivative of DMS and mercaptopyridine was eluted by mobile phase phase A: water, phase B: acetonitrile, ∶ the volume ratio was 40 60) , and separated with a C18 column, then detected with diode array detector and quantitated by a Results - standard curve. The linear range of DMS was 0.17 40.00 mg/L, with the correlation coefficient of 0.999 95. The detection limit and the lower limit of quantitation were 0.05 and 0.17 mg/L respectively. The minimum detection concentration and minimum quantitation concentration were 0.02 and 0.04 mg/m³, respectively (air sample volume of 4.5 L, 1.0 mL sample - - - solution). The average desorption efficiency was 98.40% 102.00%. The within run and between run relative standard deviations - - were 0.61% 3.92% and 1.71% 6.00%, respectively. The samples could be stored at room temperature for at least 14 days. Conclusion This method can be used to detect DMS in workplace air.

Chloro-nitrobenzene compounds air sampling tube preparation and determination method / 中国职业医学

@#Objective - - To prepare the GDH 5 air sampling tube for simultaneous collection of eight kinds of chloro nitrobenzene （ ） ， compounds CNBs in the air of workplace and establish a matching determination method using gas chromatography. Methods - - ， Eight kinds of CNBs in vapor and aerosol state were collected by self developed GDH 5 air sampling tube desorbed ， ， ， by toluene separated by polysiloxane gas chromatography column detected by microcell electron capture detector and Results - （ - quantified by external standard method. It was determined that the air sampling tube was assembled by XAD 2 ion ） - ， exchange resin and glass fiber filter membrane. The linear range of CNBs was 0.80 240.00 mg/L and the linear correlation - - coefficients were greater than 0.999 9. The detection limit was 7.87 13.03 μg/L. The minimum detectable concentration was 0.60 3， - 3（ ） 1.33 μg/m and the minimum quantitative concentration was 2.00 4.22 μg/m sample 45.00 L . The average desorption - - （RSD） - ， - RSD efficiency was 101.2% 110.0%. The within run relative standard deviation was 0.8% 4.1% and the between run - Conclusion - was 0.3% 5.8%. The samples could be stored for more than 30 days at room temperature. GDH 5 air sampling tube and its associated determination method can be used for the collection and determination of eight kinds of CNBs in workplace air.

Relationship of urine cobalt and individual exposure levels of cobalt and its compounds in cobalt exposed workers / 中国职业医学

@#Objective - To analyze the relationship between cobalt level of post shift urine and individual exposure level of ， cobalt and its compounds in cobalt exposed workers and to explore the feasibility of using urine cobalt as a biomarker. Methods - A total of 148 occupational cobalt exposed workers from a new material company were selected as the exposed ， - - group and 44 non occupational cobalt exposed workers from the company were selected as the control group using the typical sampling method. The exposure concentration of time weighted average of cobalt and its compounds in the workplace air of the - two groups was determined by inductively coupled plasma mass spectrometry as the individual exposure level. The cobalt levels - - of pre shift and post shift urinary samples of the two groups were detected by this method. The linear relationship between the - cobalt level of post shift urine and the individual exposure level of cobalt and its compounds in the air of the workplace was Results - 3 analyzed. The individual exposure level of cobalt and its compounds in the exposed group was 1.10 131.71 μg/m with （M） 3 the median of 12.23 μg/m. No cobalt and its compounds were detected in the workplace air in the control group. The cobalt - - levels of pre shift and post shift urines in exposed group were higher than those in the control group at the same time point （M： vs ， vs ， P ） - - 1.54 0.56 μg/L 8.77 0.83 μg/L all <0.01 . The cobalt level of post shift urine was higher than that in pre shift （M： vs ，P ）， urine in the exposed group 8.77 1.54 μg/L <0.01 and it was positively correlated with the individual exposure level （ ，P ） ， of cobalt and its compounds Spearman correlation coefficient=0.86 <0.01 . After common logarithm conversion the linear regression equation of the cobalt level of post shift urine and the common logarithm of individual exposure level of cobalt and （x） ：ŷ x（ ；F ， its compounds in the exposed group was as follows = −0.178 + 0.988 coefficient of determination=0.72 =374.75 P ；t ， P ） Conclusion - <0.01 = - 19.36 <0.01 . There was a linear correlation between cobalt level of post shift urine and occupational cobalt exposure level of cobalt exposed workers. Urinary cobalt can be used as a biomarker of occupational cobalt

Modified effect of urinary cadmium on breast cancer risk by selenium.

BACKGROUND: Previous experimental studies have shown an antagonistic interaction between cadmium and selenium. We explored the interaction between cadmium and selenium on human breast cancer risk. METHODS: A case-control study, enrolled 240 incident invasive breast cancer patients and 246 age-matched controls from 2 hospitals, was conducted in Guangzhou, China. Inductively coupled plasma mass spectrometry was used to examine urinary concentrations of cadmium and selenium. Association and interaction of the metal levels with breast cancer risk were tested using generalized additive and logistic regression models. RESULTS: As continuous variables, urinary cadmium [OR (95% CI): 1.16 (1.01-1.34)] but not selenium was significantly linearly associated with breast cancer risk. As tertiles, urinary cadmium did not significantly increase breast cancer risk; whereas women with the second tertile of selenium concentration had a significantly decreased risk of breast cancer as compared with those in the lowest tertile [OR (95% CI): 0.50 (0.30-0.81)]. Among the women with the lowest tertile of selenium, the highest tertile of cadmium significantly increased the risk of breast cancer [OR (95% CI): 2.83 (1.18-6.86)] compared to the lowest tertile of cadmium. A multiplicative interaction was found between tertiles of cadmium and selenium on breast cancer risk (P=0.018), particularly among postmenopausal women. CONCLUSIONS: These results suggested that the association of urinary cadmium with breast cancer risk was modified by urinary selenium.

[Study on the solid sorbent tube for capturing mercury in the workplace air and determination by cold vapor atomic absorption spectrometry].

A new KMnO4-MnO2 solid multisorbent tube for capturing mercury in workplace air was developed. Experimental conditions for solid multisorbent tube, efficiency of sampling, desorption efficiency and stability were studied. Mercury and its compounds in air were captured by solid KMnO4-MnO2 sorbent filled tube and desorbed with 0. 90 mol L-1 sulfuric acid solution. Mercury and its compounds were quantitatively analyzed according to the method of GBZ/T 160. 14-2004 cold vapor atomic absorption spectrometry. The linear range of the proposed method was 0. 000 2-0. 015 0 mg L-1 with r=0. 999 1, the average efficiency of sampling was 99. 9%-100. 0% in the concentration range of 0. 001-2. 820 mg m-3 , and the breakthrough capacity was more than 505.4 microg for 300 mg KMnO4-MnO2 solid multisorbent, the average recovery rate was 96. 4% approximately103. 8%, the intra-day and inter-day precision was 3. 0% approximately 3. 3% and 3. 5% approximately 5. 2% respectively, the limit of detection was 0. 0013 mg m-3 (7. 5 L of air ) and 0. 000 6 mg m-3 (96 L of air), after sampling, and the solid multisorbent tube could be kept at least 30 d at room temperature without significant loss. The present method was simple and suitable for capturing mercury and its compounds in the workplace air and ambient air. The solid multisorbent tube was useful for personal sampling and time weighted average sampling.

[Association between urinary cadmium and clinicopathological characteristics of breast cancer].

OBJECTIVE: The aim of this study was to investigate the association between urinary cadmium and clinicopathological characteristics of breast cancer. METHODS: The clinicopathological characteristics of 240 patients with breast cancer were obtained and urine specimens were collected from October 2009 to July 2010. The concentration of urinary cadmium was determined by inductively coupled plasma mass spectrometry (ICP-MS). χ(2) test and Wilcoxon rank sum test were used to analyze whether urinary cadmium is associated with clinicopathological characteristics of breast cancer. RESULTS: The median concentration of urine cadmium of 240 patients was 1.99 µg/g (25th percentile, 1.32 µg/g; 75th percentile, 2.88 µg/g). HER-2 positive rate, regional/distant metastasis rate, and advanced stage rate in patients with the highest tertile of cadmium concentration were significantly higher than those in the patients with second and lowest Cd tertiles (P = 0.042, P = 0.028 and P = 0.017, respectively), and 28.2% vs. 16.5% for HER-2 and 47.2% vs. 32.0% for regional/distant metastasis, respectively. There were still significant associations between urinary cadmium levels and these clinicopathological parameters after being adjusted in age by unconditional logistic regression model, respectively (P < 0.05). CONCLUSIONS: The results of this study suggest that urinary cadmium levels are associated with the HER-2 status, regional/distant metastasis status and stages of breast cancer, respectively. Cadmium may induce highly aggressive breast cancer in humans.

[Distribution of chromium in whole blood and urine among general population in China between year 2009 and 2010].

OBJECTIVE: To evaluate the chromium (Cr) levels in blood and urine among general population in China between 2009 and 2010, and thereby to analyze its prevalent features. METHODS: From year 2009 to 2010, a total of 11 983 subjects of general population aged between 6 and 60 year-old were recruited from 24 districts in 8 provinces in eastern, central and western China mainland, by cluster random sampling method. The information about their living environment and health status were collected by questionnaire, and 11 983 blood samples and 11 853 urine samples were also collected. Inductively coupled plasma mass spectrometry (ICP-MS) was applied to test the Cr level both in blood and urine; and the Cr distribution in blood and urine among groups of population in different ages, genders and districts, were then analyzed. RESULTS: Among general population in China, the geometric mean (GM) of Cr concentration in blood was 1.19 µg/L, with median at 1.74 µg /L and 95% percentile at 5.59 µg/L. The Cr concentration in blood among males and females were separately 1.18 µg/L and 1.20 µg/L(P > 0.05); while its GM in the groups of population aged 6 - 12, 12 - 16, 16 - 20, 20 - 30, 30 - 45 and 45 - 60 years old were 1.00, 1.22, 1.01, 1.40, 1.27 and 1.30 µg/L (P < 0.01), respectively; and the figures in populations from eastern, central and western China were 1.00, 1.70 and 1.98 µg/L (P < 0.01), respectively. Among general population, the GM of Cr concentration in urine was 0.53 µg/L, with median was lower than 0.42 µg/L and 95% percentile at 3.53 µg/L. The Cr concentration in urine among males and females were separately 0.52 µg/L and 0.53 µg/L (P > 0.05);while its GM in the groups of population aged 6 - 12, 12 - 16, 16 - 20, 20 - 30, 30 - 45 and 45 - 60 years old were 0.56, 0.60, 0.52, 0.50, 0.52 and 0.46 µg/L (P < 0.01), respectively;and the figures in populations from eastern, central and western China were 0.58, < 0.42 and 0.60 µg/L (P < 0.01), respectively. CONCLUSION: The study reported the Cr levels in blood and urine among general population in China, and thereby provided basic data evidence for the following Cr biological monitoring studies in near future.

Urinary titanium and vanadium and breast cancer: a case-control study.

Titanium and vanadium are essential trace elements. This study examined the associations of urinary titanium and vanadium with breast cancer risk in a hospital-based case-control study comprising 240 women with incident breast cancer, and 246 cancer-free and age-matched controls who attended health screening assessments in 2 affiliated hospitals of Sun Yat-sen University in Guangzhou between October 2009 and July 2010. Survey data and urine specimens were collected before treatment for the patients and after interview for the controls. The urinary concentrations of titanium and vanadium were measured by inductively coupled plasma mass spectrometry. Women in the second and the highest tertile of vanadium showed 64% and 40% decreased risk of breast cancer, respectively, when compared with those in the lowest tertile after adjustment for established risk factors of breast cancer (ORs [95%CI]: 0.36 [0.21-0.60] and 0.60 [0.37-0.97], respectively). In contrast, urinary titanium was not significantly related to a decreased risk of breast cancer. These results have potentially significant implications on nutritional chemoprevention of breast cancer and the development of new anticancer drugs. Further replications of the study are recommended, and the biological mechanisms warrant clarification.

Urinary strontium and the risk of breast cancer: a case-control study in Guangzhou, China.

Strontium has been widely used in industries like electronic and pharmacy. It has a carcinogenic potential, however, and no study has been conducted to evaluate its effects on cancer risk. The aim of this study was to explore the possible association between strontium and breast cancer risk in a case-control study including 240 incident invasive breast cancer patients and 246 age-matched controls. We measured the urinary concentrations of strontium by inductively coupled plasma mass spectrometry, and conducted face-to-face interviews to obtain information on potential breast cancer risk factors. Multivariable analysis was used to estimate the association. Creatinine-adjusted levels [median (25th, 75th) µg/g] of strontium were 155.59 (99.05, 230.70) in the breast cancer patients and 119.62 (81.97, 163.76) in the controls. Women in the highest tertile of strontium showed 124% increased risk of breast cancer, when compared with those in the lowest tertile after adjustment for the potential risk factors [OR (95% CI): 2.24 (1.42-3.81)]. This association was particularly strong for HER2 positive breast cancer [OR (95% CI): 10.92 (3.53-33.77)], and only occurred among premenopausal women. These results suggest a potential role of strontium in the development of breast cancer and urge further studies on the environmental contamination and the physiological and pathological mechanisms of strontium.

[Study on preparation of lanthanum-doped TiO2 nanometer thin film materials and its photocatalytic activity].

In this paper, lanthanum-doped TiO2 nanometer film materials coated on glass were prepared in Ti(OBu)4 precursor solutions by sol-gel processing. Transmittance and photocatalytic activity were respectively investigated and tested for these nanometer thin films prepared with different amount of lanthanum (La), different amount of polyethylene glycol (PEG), and different coating layer times. Some reactive mechanisms were also discussed. For one layer La-addition had little effect on the film transmissivity; but the photocatalytic activity was significantly improved due to La-addition. With increasing PEG, the transmittance of the film decreased for one layer film; but its photocatalytic activity did not rise. Increasing layer number did not affect the transmissivity of multilayer film. After coating two times, increasing layer number did not significantly improve the photocatalytic activity. The highest photocatalytic activity and best transmissivity were obtained for two layer TiO2 film when the dosage of lanthanum was 0.5 g and the dosage of polyethylene was 0.2 g in the precursor solutions. These materials will probably be used in the protection of environment, waste water treatment, and air purification.