人尿中4种有机磷酸酯阻燃剂代谢物的固相萃取-高效液相色谱-串联质谱测定法

目的建立人尿中磷酸二(1,3-二氯异丙基)酯(BDCPP)、磷酸二(2-氯丙基)酯(BCPP)、磷酸二甲苯酯(BCP)和磷酸二苯酯(DPHP)4种有机磷酸酯阻燃剂代谢物(DAPs)的固相萃取-高效液相色谱-串联质谱检测方法。方法取尿样2ml,加2 ml水稀释,以Strata TM-X-AW弱阴离子交换柱富集净化,微弱氮气吹干后,25%甲醇-水复溶至400μl,过0.22μm尼龙滤膜,1 mmol/L乙酸铵水溶液-甲醇为流动相,经DIKMA HPLC Spursil C18色谱柱(250 mm×2.1 mm,3μm)梯度洗脱分离,电喷雾离子源负离子模式(ESI-),多反应监测(MRM)模式检测。结果 DPHP、BDCPP、BCP在0.05～200μg/L、BCPP在0.1～250μg/L的线性范围内,各目标化合物的回归方程均呈良好的线性关系,r0.999。该方法的检出限为0.01～0.4μg/L,定量下限为0.05～1.3μg/L;平均回收率为63.0%～109.4%,RSD为2.1%～13.1%。结论该方法操作简单,灵敏可靠,适用于人尿中4种有机磷酸酯代谢物的同时测定。     

高效液相色谱-串联质谱法测定化妆品中10种抗生素

目的建立化妆品中盐酸美满霉素、二水土霉素、盐酸四环素、盐酸金霉素、盐酸多西环素、氯霉素、甲硝唑、林可霉素、克林霉素及克林霉素磷酸酯10种抗生素的高效液相色谱-串联质谱检测方法。方法样品经甲醇+0.1 mol/L甲酸溶液(1+1,V/V)涡旋超声提取后,经Agilent ZORBAX SB-C_(18)色谱柱(4.6 mm×75 mm,3.5μm)分离,以0.2%甲酸水溶液为流动相A,0.2%甲酸的甲醇溶液为流动相B,梯度洗脱;流速为0.5 ml/min;进样量为5μl;柱温为30℃。串联质谱正离子模式检测。结果 10种抗生素线性范围为20 ng/ml~2 000 ng/ml(r0.998),检出限0.04μg/g,在0.50μg/g、2.0μg/g及16.0μg/g 3种加标浓度下,10种抗生素平均回收率为76.8%~96.9%,RSD为1.5%~7.2%。结论该方法快速简便,具有良好的选择性、灵敏度及准确度,适用于化妆品中盐酸美满霉素等10种抗生素的测定。     

柱前衍生-气相色谱法测定饮用水中的2,4-滴

目的建立柱前衍生-气相色谱法测定饮用水中的2,4-滴的方法。方法取200 ml经过酸化的水样(p H值1),用二氯甲烷萃取,无水硫酸钠脱水,旋转蒸发仪浓缩至近干,加入甲醇∶三氟化硼乙醚(9∶1,V/V)溶液于90℃加热30 min衍生,放冷后用正己烷提取,上清液经HP-5色谱柱(30 m×320μm,0.25μm)分离后,ECD检测,标准曲线法定量。结果 2,4-滴在0μg/L～100μg/L时保持良好的线性关系(r=0.999 3)。线性范围比国家标准法扩大了4倍。回归方程y=283.20x+240.9,方法最低检出质量浓度为0.039μg/L,低于国家标准要求的0.05μg/L。相对标准偏差(RSD)为1.2%。分别做了低、中、高3个浓度的加标回收实验,回收率为91.2%～102.8%。结论本方法简便、快速、准确、灵敏度高、反应条件容易控制,适用于基层实验室对饮用水中2,4-滴的检测。     

同位素稀释-超快速液相色谱-串联质谱法测定血清中25-羟基维生素D

目的建立一种快速、准确测定血清中25-羟基维生素D_2、25-羟基维生素D3和3-epi-25-羟基维生素D3的同位素稀释-超快速液相色谱-串联质谱法。方法血清样品经甲醇-乙腈沉淀蛋白后,采用正己烷萃取,萃取液利用氮气吹扫浓缩并以初始流动相为溶剂进行定容,以含0.1%甲酸的水溶液(V/V)和含0.1%甲酸的甲醇溶液(V/V)为流动相,采用梯度洗脱方式在Phenomenex Kinetex F5色谱柱(2.1 mm×150 mm,1.7μm)上实现快速分离,采用多反应监测正离子模式检测,同位素内标法定量。结果差向异构体25-羟基维生素D_3和3-epi-25-羟基维生素D_3在6 min内可达基线分离,并可准确定量测定25-羟基维生素D_2、25-羟基维生素D_3和3-epi-25-羟基维生素D_3。3种目标物在0.5～50.0μg/L范围内均呈良好线性关系(相关系数r>0.9995),方法检出限为0.15μg/L,定量限为0.5μg/L。在3个加标水平(1.0、10.0和30.0μg/L)下,回收率为84.3%～109.0%(n=11),相对标准偏差(RSDs)为0.8%～6.8%。采用美国国家标准与技术研究院(NIST)的有证标准物(SRM 972a)的Level 1、Level 2、Level 3和Level 4进行方法验证,测定结果与标准参考值的相对偏差均小于5%。结论建立的方法具有简便、快速、灵敏和准确的特点,适用于血清中25-羟基维生素D_2、25-羟基维生素D_3和3-epi-25-羟基维生素D_3的同时测定。     

饮用水中有机磷阻燃剂磷酸三(2-氯乙基)酯和磷酸三(2-氯丙基)酯残留的固相萃取-气相色谱火焰光度测定法

目的建立饮用水中磷酸三(2-氯乙基)酯(TCEP)和磷酸三(2-氯丙基)酯(TCMEP)残留量的固相萃取-气相色谱火焰光度(GC-FPD)测定法。方法采用Oasis HLB固相萃取(SPE)柱对饮用水中有机磷阻燃剂进行提取和富集,采用GCFPD进行测定,HP-5色谱柱(30 m×0.32 mm,0.25μm)。结果 TCEP、TCMEP分别在375~7 500、200~5 000μg/L的线性范围内,所得回归方程均呈较好的线性关系(r0.998),检出限分别为165、250 ng/L,定量下限分别为550、833 ng/L。该方法对TCEP的回收率为94%~117%,RSD为1.0%~6.5%;对TCEP的回收率为107%~118%,RSD为2.4%~4.5%。结论该方法具有准确度和精密度均较高、重现性好的优点,适合生活饮用水中有机磷阻燃剂TCEP和TCMEP残留的测定。     

水果中灭螨醌和羟基灭螨醌残留的高效液相色谱法测定

目的建立水果中灭螨醌和羟基灭螨醌残留的固相萃取-高效液相色谱测定方法。方法水果样品经正己烷/乙酸乙酯(1∶1,V/V)溶液提取后,采用Cleanert Pesti Carb/NH_2固相萃取小柱净化,洗脱液经氮气流吹干后用0.1%(V/V)甲酸-乙腈(10∶90,V/V)溶液溶解。以Shim-pack XR-ODSⅡ柱(75 mm×2.0 mm,2.2μm)为分离柱、0.1%(V/V)甲酸-乙腈(10∶90,V/V)为流动相,等度洗脱,250 nm波长下进行紫外检测,外标法定量。结果灭螨醌和羟基灭螨醌在0.05 mg/L~5.0 mg/L具有良好的线性(r0.999 0),检出限为0.002 mg/kg,定量限为0.007 mg/kg,回收率为84.5%~97.6%,相对标准偏差为1.7%~4.0%。结论本法具有简便、快速、准确的优点,可用于水果中灭螨醌和羟基灭螨醌的残留测定。     

超高效液相色谱-串联质谱法测定织纹螺中腹泻性贝类毒素的实验研究

目的建立织纹螺组织中3种腹泻性贝类毒素(diarrhetic shellfish toxins,DSTs):大田软海绵酸(okadaic acid,OA);鳍藻毒素-1(dinophysistoxin-1,DTX-1);鳍藻毒素-2(dinophysistoxin-2,DTX-2)的超高效液相色谱-串联质谱(UPLC-MS/MS)检测方法。方法样本经甲醇∶水(4∶1,V/V)溶液提取,经正己烷脱脂和C18固相萃取柱净化,经ACQUITY UPLC BEH C18(1.7μm,2.1mm×100mm)色谱柱分离,乙腈-甲酸溶液(10 mmoL/L)为流动相,流速为0.2 ml/min,柱温为30℃,负离子扫描,在多反应监测(MRM)模式下进行定性与定量分析。结果 OA、DTX-1、DTX-2在(0.01~0.20)mg/L范围内线性关系良好,3个添加水平的平均回收率为80.3%~93.6%,相对标准偏差(RSD)为2.13%~4.23%。其定量限(LOQ)为6.93μg/kg、3.3μg/kg、4.95μg/kg。结论利用此方法发现福建织纹螺中含有腹泻性贝类毒素,方法灵敏度高,操作简便,适用于实际样本的分析检测。     

固相萃取-超高效液相色谱-高分辨质谱法测定尿液中草甘膦

目的建立尿液中草甘膦的固相萃取-超高效液相色谱-高分辨质谱(UPLC-HRMS)分析方法。方法尿液样品采用0.1%(V/V)甲酸-乙腈沉淀蛋白后,利用MCX阳离子交换固相萃取小柱净化,采用Phenomenex Luna NH2柱(50 mm×4.6 mm,3μm)为分离柱,以乙腈/10 mmol/L乙酸铵-0.1%(V/V)氨水溶液为流动相进行梯度洗脱,采用电喷雾负离子源在选择离子监测模式(SIM)下检测,定量检测离子为m/z 168.006 7。结果尿液中草甘膦在1.0μg/L~100.0μg/L具有良好的线性关系,相关系数(r)为0.999 2,尿液中草甘膦的检出限(S/N=3)为0.3μg/L,定量检出限(S/N=10)为1.0μg/L,方法的回收率在92.0%~97.2%,低、中、高3个添加水平浓度的日内RSD为2.4%~4.4%,日间RSD为3.3%~6.9%。结论建立的方法准确、简便、灵敏,可用于中毒者尿液中草甘膦的检测。     

工作场所空气中2, 3-丁二酮测定的衍生化-高效液相色谱法

目的建立磷酸溶液采集、衍生化-高效液相色谱法测定工作场所空气中2, 3-丁二酮(简称丁二酮)。方法于2022年10月, 用多孔玻板吸收管盛装0.01%的磷酸溶液10 ml, 以0.2 L/min流量采集工作场所空气中丁二酮, 吸收液经2, 4-二硝基苯肼衍生化75 min, SB-C18色谱柱(250 mm×4.6 mm, 5 μm)分离, 在30 ℃柱温下, 用乙腈-水(V∶V, 1∶1)混合液作流动相, 以1.0 ml/min的流速洗脱, 紫外检测器(λ=365 nm)检测, 保留时间定性, 外标法定量。结果本方法中丁二酮的磷酸溶液吸收样在4 ℃下可保存7 d, 在0.05～6.00 μg/ml范围内线性关系良好, 线性回归方程为y=89.610x+0.133, r=0.999 9, 采样效率为98.33%～100.00%, 方法的检出限为0.005 μg/ml, 最低检出浓度为0.016 mg/m3(以V0=3.0 L计), 方法回收率为95.96%～102.44%, 批内精密度为4.36%～7.78%, 批间精密度为4.96%～6.06%。结论本方法简单实用, 准确度好, 灵敏...     

混合型阳离子交换固相萃取-液相色谱-串联质谱法测定肉样中特布他林、沙丁胺醇、莱克多巴胺和克伦特罗残留

目的建立一种灵敏和准确地检测肉制品中特布他林、沙丁胺醇、莱克多巴胺和克伦特罗4种β2-受体激动剂残留的快速分析方法。方法肉制品经2%磷酸甲醇-水溶液(80∶20,V/V)涡旋提取10 min,离心,上清液经乙酸酸化后采用混合型阳离子交换固相萃取小柱(MCX)净化,以乙腈和0. 1%(V/V)甲酸水溶液作为流动相,在反相C18柱上进行梯度洗脱与色谱分离,以三重四级杆串联质谱(MS/MS)进行检测,内标法定量。结果 4种β2-受体激动剂在0. 2μg/L～100. 0μg/L呈现较好的线性关系(r≥0. 999 2),方法的检出限(LODs)为0. 03μg/kg～0. 08μg/kg。当加标水平为1. 0μg/kg、40. 0μg/kg和80. 0μg/kg时,肉制品中4种β2-受体激动剂的加标回收率为86. 2%～101. 3%,相对标准偏差(RSD)为1. 1%～8. 3%。结论本法可用于猪肉、猪肝、牛肉和牛肝等肉制品中常见β2-受体激动剂残留检测与分析。     

Emerging pollutants in the North Sea in comparison to Lake Ontario, Canada, data

In the present study, the concentrations and fate of contaminants such as organophosphate flame retardants and plasticizers, musk compounds such as galaxolide (HHCB), tonalide (AHTN), musk ketone and musk xylene, the bactericide triclosan, as well as the metabolites HHCB-lactone and triclosan-methyl were compared in the aqueous phase of the German Bight (North Sea). The concentrations of these compounds were around 1 to 10 ng/L in nearshore areas, and the concentrations were lower in the more pristine areas. The highest concentrations were determined for tris-(2-chloro-isopropyl) phosphate in the North Sea with concentration exceeding 10 ng/L even for the offshore samples. The samples contained 1 to 20 ng/L chlorinated organophosphates, approximately 1 ng/L nonchlorinated organophosphates, and 0.3 to 3 ng/L fragrance compounds. Some samples from Lake Ontario (Canada) were analyzed in comparison. Per capita emissions were calculated for both regions. These emissions were compared and turned out to be very similar for the Canadian and German locations. For the North Sea, some observations concerning stability, dilution, and degradation, as well as sources of the respective substances, were performed. These data indicate that the chlorinated organophosphates and some musk fragrances exhibit half lives exceeding the residence times and thus can be considered to be persistent in this ecosystem. In the German Bight, the river Elbe is the dominating source for the more hydrophilic compounds, such as chlorinated organophosphate flame retardants, which are diluted only into the North Sea. However, for the more lipophilic compounds such as the musk fragrances, different input patterns as well as distribution patterns are relevant, though the river Elbe is still a major source of pollution to the German Bight of the North Sea. The data seem to indicate either relevant inputs further west of the sampling area or mobilization from the sediments.     

Organophosphate Flame Retardants in House Dust from South China and Related Human Exposure Risks

House dust associated with organic pollutants is not only a potential source of pollutants to the outdoor environment, but also a source to human exposure. The present study investigated the occurrence and concentrations of organophosphate flame retardants (OPFRs) in house dust collected from South China dwellings (n?=?20). The results revealed a universal presence of most target OPFRs in house dust, with concentrations of ΣOPFRs ranging from 2.06 to 19.95 μg/g. The median concentration of ΣOPFR (9.20 μg/g) was one order of magnitude greater than that of polybrominated diphenyl ethers (0.80 μg/g). The composition of OPFR chemicals in house dust was dominated by chlorinated OPFRs, such as tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and tris(1-chloro-2-propyl) phosphate (TCPP). This compositional pattern was different from what has been reported in indoor dust from many other countries, where tris(2-butoxyethyl) phosphate (TBEP) was generally dominant. The daily intake of OPFRs by adults was estimated to be 1.6 and 4.2 ng/kg body weight/day under average and high exposure scenarios, respectively, and 31.7 and 127 ng/kg body weight/day for toddlers.     

Urinary Metabolites of Organophosphate Flame Retardants: Temporal Variability and Correlations with House Dust Concentrations

Background: A reduction in the use of polybrominated diphenyl ethers (PBDEs) because of human health concerns may result in an increased use of and human exposure to organophosphate flame retardants (OPFRs). Human exposure and health studies of OPFRs are lacking.Objectives: We sought to define the degree of temporal variability in urinary OPFR metabolites in order to inform epidemiologic study design, and to explore a potential primary source of exposure by examining the relationship between OPFRs in house dust and their metabolites in urine.Methods: Nine repeated urine samples were collected from 7 men over the course of 3 months and analyzed for bis(1,3-dichloro-2-propyl) phosphate (BDCPP) and diphenyl phosphate (DPP), metabolites of the OPFRs tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and triphenyl phosphate (TPP), respectively. Intraclass correlation coefficients (ICCs) were calculated to characterize temporal reliability. Paired house dust and urine samples were collected from 45 men.Results: BDCPP was detected in 91% of urine samples, and DPP in 96%. Urinary BDCPP showed moderate-to-strong temporal reliability (ICC range, 0.55–0.72). ICCs for DPP were lower, but moderately reliable (range, 0.35–0.51). There was a weak [Spearman r (r_S) = 0.31] but significant (p = 0.03) correlation between urinary BDCPP and TDCPP concentrations in house dust that strengthened when nondetects (r_S = 0.47) were excluded. There was no correlation between uncorrected DPP and TPP measured in house dust (r_S < 0.1).Conclusions: Household dust may be an important source of exposure to TDCPP but not TPP. Urinary concentrations of BDCPP and DPP were moderately to highly reliable within individuals over 3 months.     

正己烷在静态染毒柜中浓度变化与时间的关系

目的:用静态染毒柜进行正己烷染毒,研究染毒柜内正己烷浓度变化与时间关系。方法:分别在染毒后0、60、120、180和240 min吸取静态染毒柜中的气体,用气相色谱仪测定正己烷浓度。结果:低剂量正己烷(2.0g/m3)在染毒0~180 min内浓度相对较稳定,不同时间段正己烷浓度没有显著性差别(P>0.05),直到240 min时浓度才有明显下降(P<0.05)。中剂量正己烷(10.0 g/m3)在染毒0~60 min时间浓度变化较小(P>0.05),120 min时浓度明显下降(P<0.05),但120~180 min浓度又趋于稳定。高剂量正己烷(50.0 g/m3)染毒,其浓度随染毒时间延长明显下降,各检查点浓度都有显著性差别(P<0.05)。结论:使用静态染毒柜染毒低剂量正己烷浓度能维持较长时间的恒定,中剂量维持浓度恒定时间较短,高剂量正己烷染毒不适合用静态染毒柜。     

Monitoring Indoor Exposure to Organophosphate Flame Retardants: Hand Wipes and House Dust

Background: Organophosphate flame retardants (PFRs) are becoming popular replacements for the phased-out polybrominated diphenyl ether (PBDE) mixtures, and they are now commonly detected in indoor environments. However, little is known about human exposure to PFRs because they cannot be easily measured in blood or serum.Objectives: To investigate relationships between the home environment and internal exposure, we assessed associations between two PFRs, tris(1,3-dichloropropyl) phosphate (TDCIPP) and triphenyl phosphate (TPHP), in paired hand wipe and dust samples and concentrations of their metabolites in urine samples (n = 53). We also assessed short-term variation in urinary metabolite concentrations (n = 11 participants; n = 49 samples).Methods: Adult volunteers in North Carolina, USA, completed questionnaires and provided urine, hand wipe, and household dust samples. PFRs and PBDEs were measured in hand wipes and dust, and bis(1,3-dichloropropyl) phosphate (BDCIPP) and diphenyl phosphate (DPHP), metabolites of TDCIPP and TPHP, were measured in urine.Results: TDCIPP and TPHP were detected frequently in hand wipes and dust (> 86.8%), with geometric mean concentrations exceeding those of PBDEs. Unlike PBDEs, dust TDCIPP and TPHP levels were not associated with hand wipes. However, hand wipe levels were associated with urinary metabolites. Participants with the highest hand wipe TPHP mass, for instance, had DPHP levels 2.42 times those of participants with the lowest levels (95% CI: 1.23, 4.77). Women had higher levels of DPHP, but not BDCIPP. BDCIPP and DPHP concentrations were moderately to strongly reliable over 5 consecutive days (intraclass correlation coefficients of 0.81 and 0.51, respectively).Conclusions: PFR exposures are widespread, and hand-to-mouth contact or dermal absorption may be important pathways of exposure.Citation: Hoffman K, Garantziotis S, Birnbaum LS, Stapleton HM. 2015. Monitoring indoor exposure to organophosphate flame retardants: hand wipes and house dust. Environ Health Perspect 123:160–165; http://dx.doi.org/10.1289/ehp.1408669     

常见还原性物质还原五价无机砷的实验研究

目的研究还原型谷胱甘肽(GSH)、半胱氨酸(Cys)、维生素C(VC)和亚铁离子(Fe2+)等常见还原性物质对五价无机砷[As(Ⅴ)]的还原作用及特点。方法模拟体内环境建立还原体系[37℃、pH7.0的磷酸盐缓冲液、3μmol/L As(Ⅴ)、60mmol/L巯基化合物(GSH和Cys)、0~30mmol/L VC、0~40mmol/LFe2+],采用高效液相色谱-氢化物发生-原子荧光法(HPLC-HG-AFS)检测各种反应过程中的三价无机砷[As(Ⅲ)]和As(Ⅴ)。结果As(Ⅴ)还原率和As(Ⅲ)生成率随GSH浓度增加(0~60mmol/L)而增加;当GSH浓度为60mmol/L时,As(Ⅴ)还原率和As(Ⅲ)生成率达到峰值;随着GSH浓度继续增加(60~80mmol/L),As(Ⅴ)还原率和As(Ⅲ)生成率反而下降;巯基化合物中的巯基(-SH)在还原As(Ⅴ)过程中起关键作用,60mmol/L的-SH反应30分钟后As(Ⅴ)还原率达到60%,As(Ⅴ)还原率与-SH的具体存在形式(GSH或Cys)无关;单独VC或Fe2+不能还原As(Ⅴ),但是当VC浓度大于10mmol/L或Fe2+浓度大于20mmol/L时,可以增加60mmol/L的-SH的还原作用(P<0.01)。结论巯基化合物中的-SH可以非酶促还原As(Ⅴ),VC和Fe2+可以增强-SH的还原作用。     

Characterizing the Peroxisome Proliferator-Activated Receptor (PPARγ) Ligand Binding Potential of Several Major Flame Retardants,Their Metabolites,and Chemical Mixtures in House Dust

Background: Accumulating evidence has shown that some environmental contaminants can alter adipogenesis and act as obesogens. Many of these contaminants act via the activation of the peroxisome proliferator-activated receptor γ (PPARγ) nuclear receptor.Objectives: Our goal was to determine the PPARγ ligand binding potency of several major flame retardants, including polybrominated diphenyl ethers (PBDEs), halogenated phenols and bisphenols, and their metabolites. Ligand binding activity of indoor dust and its bioactivated extracts were also investigated.Methods: We used a commercially available fluorescence polarization ligand binding assay to investigate the binding potency of flame retardants and dust extracts to human PPARγ ligand-binding domain. Rosiglitazone was used as a positive control.Results: Most of the tested compounds exhibited dose-dependent binding to PPARγ. Mono(2-ethylhexyl) tetrabromophthalate, halogenated bisphenols and phenols, and hydroxylated PBDEs were found to be potent PPARγ ligands. The most potent compound was 3-OH-BDE-47, with an IC₅₀ (concentration required to reduce effect by 50%) of 0.24 μM. The extent of halogenation and the position of the hydroxyl group strongly affected binding. In the dust samples, 21 of the 24 samples tested showed significant binding potency at a concentration of 3 mg dust equivalent (DEQ)/mL. A 3–16% increase in PPARγ binding potency was observed following bioactivation of the dust using rat hepatic S9 fractions.Conclusion: Our results suggest that several flame retardants are potential PPARγ ligands and that metabolism may lead to increased binding affinity. The PPARγ binding activity of house dust extracts at levels comparable to human exposure warrants further studies into agonistic or antagonistic activities and their potential health effects.Citation: Fang M, Webster TF, Ferguson PL, Stapleton HM. 2015. Characterizing the peroxisome proliferator-activated receptor (PPARγ) ligand binding potential of several major flame retardants, their metabolites, and chemical mixtures in house dust. Environ Health Perspect 123:166–172; http://dx.doi.org/10.1289/ehp.1408522     

Levels and distributions of organophosphate flame retardants and plasticizers in sediment from Taihu Lake, China

The concentrations and distribution of seven organophosphate flame retardants and plasticizers (OPs) were investigated in 28 sediment samples collected from Taihu Lake. The analytes were ultrasonically extracted, enriched using solid-phase extraction, and determined by gas chromatography-mass spectrometry. The results indicated that the analytes were all detected in the sediments. The total concentrations of seven OPs ranged from 3.38 to 14.25 μg/kg, and tris (2-chloroiso-propyl) phosphate (TCPP), tris (2-chloroethyl) phosphate (TCEP), and tris (2-butoxyethyl) phosphate (TBEP) were the dominant compounds, with concentrations ranging from相似文献   

Evaluation of cut-off saw exposure control methods for respirable dust and crystalline silica in roadway construction

Dust reduction equipment adapted for single-person operation was evaluated for gas-powered, commercially available cut-off saws during concrete curb cutting. Cutting was performed without dust control and with two individual exposure control methods: wet suppression and local exhaust ventilation (LEV). The wet suppression system comprised a two-nozzle spray system and a 13.3-L hand-pressurized water supply system with an optimum mean flow rate of 0.83 L/min for 16 min of cutting. The LEV system consisted of a spring-loaded guard, an 18.9-L collection bag, and a centrifugal fan with an estimated exhaust rate of 91 ft(3)/min. Task-based, personal filter samples were obtained for four saw operators during cutting durations of 4 to 16 min on five job sites. Seventeen filter samples were collected without dust control, 14 with wet suppression, and 12 with LEV, yielding a geometric mean respirable dust concentration of 16.4 mg/m(3), 3.60 mg/m(3), and 4.40 mg/m(3), respectively. A dust reduction of 78.0% for wet suppression and 73.2% for LEV was observed vs. no dust control. A statistically significant difference (p < 0.001) was also revealed for wet suppression and LEV when compared with no dust control; however, a significant difference (p = 0.09) was not observed between wet suppression and LEV. Despite these significant dust reductions, workers are still projected to exceed the ACGIH 8-hr time-weighted average threshold limit value for quartz (0.025 mg/m(3)) in less than 1 hr of cutting for both dust control methods. Further research is still needed to improve dust reduction and portability of both control methods, but the current LEV system offers important advantages, including a drier, less slippery work area and year-round functionality in cold weather.     

自动固相萃取-气相色谱-质谱法测定生活饮用水中60种半挥发性有机物

目的提出一种同时测定生活饮用水中60种半挥发性有机物的自动固相萃取-气相色谱-质谱联用法。方法1 L水样中加入5 m L甲醇,通过自动固相萃取装置使用LC-Florisil固相萃取柱对水样进行富集,再分别用5 m L二氯甲烷和5 m L乙酸乙酯洗脱,氮吹浓缩定容至1 m L,进样分析。结果60种半挥发性有机物在(0.125~4.00)μg/L的含量范围内具有较好的线性,其相关系数均≥0.99,方法检出限为(0.002~0.06)μg/L,检测限为(0.01~0.26)μg/L,回收率范围70.8%~129%,精密度(RSD)范围0.2%~21.5%。结论该方法实现了前处理过程自动化,具有准确度高、操作简单和溶剂使用量少等优点,适用于同时测定生活饮用水中60种半挥发性有机物。